Because confidence ratings related to complete images before the experimental manipulation and to partial images after the manipulation, the former were entered as covariates in an ANCOVA. Premanipulation confidence ratings for recall + EM,*F*(1, 56) = 17.38, *p* < 0.001, η 2 *p* = 0.24, and for control, *F*(1, 56) = 11.87, *p* = 0.001, η 2 *p* = 0.18, related significantly to post-manipulation confidence ratings. There was no relation between pre-manipulation recall only scores and post-manipulation ratings, *F* < 1. The main analysis of condition on post-manipulation ratings showed no effect when controlling for the pre-experimental confidence ratings, *F*(1.672, 93.641) = 0.17, *p* = 0.80, η 2 *p* = 0.003 (Huynh–Feldt correction).

**Table 1 | Means and SD (in parentheses) of difficulty, confidence, vividness, and emotionality ratings for the recall** + **EM, recall only, and control conditions**.

### **RESPONSE LATENCIES**

Before analyses, response latencies were log transformed because of natural skewness in scores.  Therefore, pre-manipulation response latencies were entered as covariates in an ANCOVA. Pre-manipulation response latencies for recall only, *F*(1, 56) = 6.70, *p* = 0.012, η 2 *p* = 0.11, related significantly to post-manipulation response latencies. Other pre-manipulation response latencies did not, *F*s < 3.10, *p*s > 0.08, η 2 *p* < 0.06. The main analysis for post-manipulation response latencies, though, did not reach significance when controlling for pre response latencies, *F*(2, 112) = 0.7, *p* = 0.5, η 2 *p* = 0.01. **Table 2** presents means and SD.

### **ACCURACY**

Participants needed, on average, 1.77 (SD = 1.30) repetitions to achieve the learning criterion. Because analyses were performed only on pairs for which participants recalled the target on the final learning test, pre-manipulation scores for accuracy reached the ceiling (100% for all conditions). Therefore, for accuracy, an ANOVA was performed on post-manipulation scores only (see **Table 2**). Participants did not differ in their accuracy to select the correct target images for the different conditions, *F*(2, 118) = 0.45, *p* = 0.64, η 2 *p* = 0.007.

### **DISCUSSION**

The aim of this study was to test whether recall + EM affect the accessibility of associative memory representations when emotionally negative materials are used. In this extended replication of Van den Hout et al. (18), we found no blurring of the emotional memory representations for recall + EM compared to recall only or no intervention. This was reflected in the absence of any effects on subjective ratings of vividness and emotionality, and also in objective measures of memory accessibility, specifically latency responses. Participants reported they had complied with the instruction to make EM. They also reported that mental images were less vivid, less detailed, and more difficult to retrieve *during* the intervention. However, this seems trivial, because these effects did not persist at the post-test.

The data show no reductions in memory accessibility, but they do not necessarily falsify WM theory as an explanation for the effects of dual taxation. The absence of effects may be a consequence of our materials. Could the data have been different if self-relevant or less negative pictures would have been used? The vast majority of earlier studies on the effects of demanding secondary tasks have used personally relevant, autobiographical memories [e.g., Ref. (10, 11, 32)], while our study used novel

**Table 2 | Means and SD (in parentheses) of response latencies and accuracy for recall** + **EM, recall only, and control conditions**.

emotional images. These images could have lacked the potential to elicit sufficient levels of arousal, which may be necessary in the dual-tasking procedure to reduce vividness (Littel et al., submitted). Van den Hout et al. (14) showed that only negative autobiographical memories – which are associated with transient levels of arousal – were reduced in their vividness ratings, while neutral memories were not. This suggests arousal is a prerequisite for (re-)encoding of memories after dual taxation. Although our materials were not negative autobiographical memories, they were, however, thoroughly piloted and showed sufficient arousal during the pilot and on pre-test measures. Moreover, other studies have used non-idiosyncratic materials and showed effects for recall + EM compared to recall only [e.g., Ref. (15)] and specifically showed that effects can be found for materials that are neither autobiographical nor self-relevant (9, 18). It therefore seems unlikely that intrinsic qualities of our novel images *per se* explain the absence of effects.

The tasks we used may also have limited the effects of dual taxation. This study used a latency response task that was based on a similar task in Van den Hout et al. (18). In their task, participants were instructed to react as fast and accurately as possible, and had to decide whether a cut-out was old or new. In our experiment, participants received comparable instructions. Yet, they did not make an old-new judgment, but a source judgment: they had to indicate which of the four displayed images was the cue's target. Though these tasks look similar, they probably draw on different types of recognition: old-new recognition and source recognition. Old-new recognition can generally be performed at lower levels of item differentiation than source decisions (33). As a consequence, slightly blurred recall + EM pairs may show effects for old-new decisions compared to recall only pairs, but not for source decisions. It is possible that successful source memory differentiation does occur when pairs from the recall + EM condition differ more in the level of memory blurring from the recall only or no-presentation control conditions. Theoretically, it may be possible to find differences between conditions when an old-new recognition task is used instead of a source recognition task.

A different explanation may also be found in the response latency task, specifically in the distractors that were used as targets in previous trials. During the final part of the experiment, participants had to select the correct target out of four cut-out images. Here, the use of distractors that have been used as targets in previous trials may cause response inhibition, and related response delays. Alternatively, it is also possible that the blurring effects were abolished, when participants specifically saw recall + EM images as distractors in earlier trials, and in later trials saw these same images as targets. As a consequence, the image could have been reinstated in full and any condition effects were abolished as well. This does not, however, explain why there were no effects on any of the subjective ratings, which preceded the response latency task. Though, it might be possible that the effects of recall + EM in our design were subtle and only detectable with RT, but that this effect was abolished by how our response latency task was designed. Furthermore, emotional interference may have played a role, because participants had to select one out of four highly unpleasant images, which may have caused response delays that are not due to simple blurring or retrieval delay. Indeed, it cannot be ruled out that there

might be a floor effect in that the delay is beyond the critical point where retrieval differences can be found.

Though several plausible explanations for the lack of effects can be found in the response latency task, it still leaves unanswered why subjective ratings of the images did not change, because these ratings preceded the latency response task, and were recalled without seeing any of the targets from other pairs. Perhaps cued recall of the to-be-recalled material influenced the effectiveness of dual taxation. On the one hand, cued recall could facilitate episodic memory retrieval compared to non-cued recall (23), and thus should allow the participant to vividly retrieve the associated target image. This is reflected in relatively low pre-test scores for self-assessed difficulty of retrieval and high scores for vividness. Subsequent retrieval of a vividly cued image should therefore be blurred as a consequence of dual taxation. This, however, did not happen. On the other hand, even though participants quickly learned the associations – which hints at strong relationships between cue and target – these may simply not have been strong enough. We used neutral words referring to objects that people may encounter frequently in daily life and thus could be linked to various situations. Although the association between the cue and target is novel and recent, it is unlikely that the cue's path exclusively leads to the target. Therefore, after images were cued in a recall + EM trial, participants may not have thought of the target image all the time, but of other images, objects, or words. As a consequence, the target may not have been sufficiently blurred and reductions in self-reported vividness and emotionality may not have been experienced for recall + EM. Hence, generally cued recall may ameliorate memory, but not when a multipath cue needs to prompt one specific target for prolonged periods of time. Additionally, this might also explain why there were no latency response effects. If cues did not elicit specific and continuous target retrieval, then differential item blurring and successful source recognition could not have occurred.

Provided that cued recall was primarily responsible for the lack of effects, the question ensues whether dual taxation is able to affect associative memory networks. A review of earlier studies showed that WM taxation, specifically EM, is able to reduce subjective ratings of emotional memories when those memories were recalled immediately after the intervention (8). The current study showed that these memories were not changed subjectively or objectively when cued with a memory reminder. Perhaps this limitation signals a boundary condition for this paradigm and limits the robustness of the dual taxation paradigm. Until now, Van den Hout et al. (18) conducted the only study that found effects of the EM intervention on objective measures of memory accessibility, and it cannot be ruled out that this represents a chance finding. It should be noted that other studies using objective measures of memory valence or emotionality have shown effects after dual taxation, such as eye blink startle reflex diminution (34), reduced heart rate variability (35), and decreased electrodermal responses (36), but these objective measures primarily related to arousal levels and not memory accessibility *per se*.

If it does, however, signal a limitation of the dual taxation paradigm, then memory change under dual taxation conditions may require a specific form of recall. This would imply that a memory must be directly recalled as opposed to memory recall that is initially cued by reminders. The former has been frequently used in previous work [e.g., Ref. (14)]. Interestingly, this does not preclude the possibility of finding effects with cued recall. Cued recall *after* dual taxation may still lead to reductions in subjective ratings, but only if the memory is recalled directly *during* dual taxation. This does, however, seem to contradict predictions from current trauma theories (20, 21), which state that encountering cues associated with an emotional memory could instantly trigger vivid intrusions of that memory. In the current study, cues probably elicited retrieval of the target memory, but most likely only briefly.

The lack of effect of cued recall also has implications for associative network theories, in which connectivity between different representations is paramount. A central tenet of network theories is modifiability of the network's structure after activation [e.g., Ref. (37)]. It is possible that small networks (e.g., two nodes representing only stimulus characteristics, such as gate – car accident) are difficult to modify. Larger, more ecologically valid networks typically also contain elements regarding responses ("panic") or meanings ("I am helpless"), next to mere stimulus relations. Perhaps these former relations are an inherent changeable part of the associative network, and also a part that does not need to be targeted directly. It is possible that stimulus characteristics change during dual taxation, and affect response and meaning elements, which changes how a person feels or thinks about an event. As a consequence, change in subjective experiences may be difficult to accomplish in smaller, laboratory created networks because these lack elements of meaning.

In sum, we found that EM during recall did not blur emotional memory representations measured by subjective or objective measures of memory accessibility. Response inhibition and emotional interference do not seem able to explain all the effects. Cued recall, on the other hand may; it may not have been potent enough to elicit specific and continuous target retrieval for differential item blurring to occur. Although memory effects following EM were not observed, it is unlikely – given the substantial body of evidence – that reductions in self-reported ratings are a chance discovery. Changes in objective measures of memory accessibility therefore still need to pass the critical test of replication.

### **ACKNOWLEDGMENTS**

This research was supported by a TOP grant (dossier number: 40- 00812-98-12030) from the Netherlands Organization for Health Research and Development (ZonMw) awarded to MvdH. We are grateful to Anne Klein Schiphorst for her assistance in piloting the materials and to Sheanen Danoe and Nikki van de Loo for their assistance in testing. We are especially thankful to the reviewers who suggested very knowledgeable and thoughtful explanations for our effects.

### **REFERENCES**

1. American Psychiatric Association. *Practice Guideline for the Treatment of Patients with Acute Stress Disorder and Post Traumatic Stress Disorder*. Arlington, VA: American Psychiatric Association Practice Guidelines (2004).

**Conflict of Interest Statement:** The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

*Received: 14 October 2014; accepted: 29 January 2015; published online: 12 February 2015.*

*Citation: van Schie K, Engelhard IM and van den Hout MA (2015) Taxing working memory during retrieval of emotional memories does not reduce memory accessibility when cued with reminders. Front. Psychiatry 6:16. doi: 10.3389/fpsyt.2015.00016*

*This article was submitted to Affective Disorders and Psychosomatic Research, a section of the journal Frontiers in Psychiatry.*

*Copyright © 2015 van Schie, Engelhard and van den Hout. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.*

# PSYCHIATRY

## Mental imagery and food consumption

### **Benjamin Missbach1\*, Arnd Florack 2 and Jürgen König1**

1 Department of Nutritional Sciences, University of Vienna, Vienna, Austria

2 Department of Psychology, University of Vienna, Vienna, Austria

\*Correspondence<EMAIL_ADDRESS>
#### **Edited by:**

David G. Pearson, University of Aberdeen, UK

#### **Reviewed by:**

Eva Kemps, Flinders University, Australia

**Keywords: mental imagery, habituation, satiation, depletion, mindfulness**

### **INTRODUCTION**

One enigmatic capacity of human experience is the ability to travel back and forth in time by using mental simulations. By imagining shapes, forms, and scenes, humans can relive the past and visualize future events (1, 2). Historically, this memory-based mechanism has been discussed in scientific and nonscientific fields. As described by Marcel Proust in his epic work, In Search of Lost Time (3), the sensory experience of gustatory cues, in this case, a spongecake called Madeleine, seems to be powerful enough to trigger a cascade of vivid intrusions associated with a particular set of memories (4).  Unraveling the basic mechanisms that underlie mental imagery in the food domain has the potential to provide new insights into the perception and consumption of food.

In this opinion article, we briefly report on the role of mental imagery simulations in eating behavior and its associated pathologies and illustrate how research on mental imaginary has contributed to the current understanding of the cognitive aspects of food intake regulation and satiation processes. Furthermore, we discuss whether guided mental imagery intervention strategies can be integrated into the successful self-regulation of eating behavior and provide a perspective for future research on mental imagery.

### **MENTAL SIMULATION OF FOOD CONSUMPTION AND EFFECTS ON JUDGMENTS AND BEHAVIOR**

Many individuals in modern society live in environments that promote excessive weight gain because of the omnipresence of food (5). The exposure to food automatically prepares individuals for food intake and often evokes thoughts about food, a simulation of food intake, and a strong motivation to consume food (6). Indeed, even the exposure to words related to tempting food can activate a cascade of associations with food (7) and the simulation or reenactment of prior eating occasions (8). Although internal cues of hunger or craving are relevant to the formation of such intrusive thoughts to a large degree, it is clear that thoughts about food consumption are also triggered by consumption-related cues in the environment. Shop design and product presentation in marketing have tapped into these mechanisms by using sensory, textural, and emotional triggers to evoke intrusions, facilitate the simulation of consumption, and increase actual purchases and consumption (9, 10). Recently, research has shown that such marketing practices are not just a creative idea put forth by marketing managers but are supported by concrete evidence for the link between mental simulations and behavior. Elder and Krishna (11) presented participants with a picture of smooth vanilla yogurt in a bowl. They varied whether a spoon was on the right or left side of the bowl. In support of the hypothesis that participants simulate their eating of the yogurt prior to their actual intake in order to forecast the taste of the yogurt, the researchers found that right-handed participants indicated

higher purchase intentions when the spoon was on the right side of the bowl compared with when it was on the left side. Hence, the characteristics of the presentation that facilitated the simulation of eating increased the motivation to eat the yogurt. The facilitation effect is not limited to visual perception. For instance, Mitchell and Kahn (12) reported that the ambient odor of a room had a considerable effect on the extent to which individuals thought about the presented products. When the odor was congruent with a product (e.g., chocolate), consumers were more likely to process information about the product. Similarly, Seo and Roidl (13) found that congruent odor enhanced visual attention to odor-congruent food items. In their study, 60 participants were presented with four odors (orange, lavender, coffee, and licorice) prior to and during the presentation of foods via photographic slides. Participants who received olfactory cues looked more frequently and for longer at the corresponding foods than participants in a control condition with no odor presentation. The presentation of food also has an effect on taste assessments. For example, subtle changes of the natural color of an orange juice drink (darker orange hue) decreases liking scores substantially (14). In accordance, manipulating expected brand pronunciation (incongruent brand labeling) was shown to reduce hedonic liking of yoghurts (15). Taken as a whole, the results of the above-mentioned studies correspond with the assumption that conditions that facilitate the simulation of the consumption of attractive food increase interest in the food (e.g., visual attention or processing of information

about the food) and the desire for food consumption.

Researchers have recently referred to theories on grounded cognition (16, 17) to explain the effects of perceptions on thoughts and behavior (10). The basic idea of these theories is that the cognitive representation of concepts is grounded in related modal systems. Previous theories on cognition had supposed that cognitions were amodal and, for example, not based on modal representations of motor behavior. These theories had implied that individuals can think about eating in the same way whether or not they can move their mouth and tongue at the current moment. By contrast, the more recent approaches of grounded cognition suppose that thinking about an object is related to perception and motor behavior. This means that humans cannot think about food without simultaneously activating related perceptions and that they simultaneously simulate motor behavior that is related to the stimulus. Hence, the mode of thinking is supposed to be strongly related to the mode of perception and the mode of action. According to the grounded cognition approach, thinking about food or just reading foodrelated words should evoke mental simulations of eating (7). Recently, such assumptions have received support from neuroscience research. Researchers found that solely the perception of pictures of palatable food led to activations in brain areas associated with gustatory experiences (18) and elevated ghrelin levels (orexigenic hormone) in healthy volunteers (19). Like food cues, ghrelin is one major mediator of food anticipation (20) and recruits the same neuronal circuitry in the dorsomedial and ventromedial hypothalamus (21).

An example of a particularly strong influence of thoughts on behavior is food craving. Food craving is regarded as a strong motivational state that urges individuals to seek and consume a particular kind of food (22), often containing high amounts of sugar or fat (23). When individuals crave food, their thoughts about food are often so intrusive that they have trouble pursuing other goals or focusing on different thoughts. For craving, the causal direction of the influence is bidirectional in the sense that craving has an influence on thought and vice versa. However, it is important to take into account that

the mental simulation of food consumption triggered by external cues as described above can result in craving.

### **REPEATED MENTAL SIMULATION AND MINDFULNESS**

### **EFFECTS OF REPEATED MENTAL SIMULATION ON FOOD CONSUMPTION**

An interesting aspect of mental simulations during food perception is that mental simulations do not necessarily lead to increased consumption, but rather, under certain circumstances, they can lead to decreased consumption. Interestingly, repeatedly thinking about food consumption can lead to habituation and a reduced motivation to consume a specific food, just like real consumption (24). Habituation to food is understood as a process that leads to a decrease in both the physiological and behavioral responses to an eating episode and a drop in enjoyment with repeated consumption (24). Several studies (25–27) have found evidence that habituation can take place when individuals repetitively judge food or imagine eating food. For instance, Morewedge et al. (26) asked participants to think either 3 or 30 times about eating M&M's. Later, participants were allowed to eat M&M's. Participants who thought about eating the candy 30 times ate less of the product than those who thought about it 3 times and those in a control condition (who imagined throwing coins into a laundry machine). Like other habituation effects, this effect was shown to be sensory-specific and was only present when the imagined food was congruent with the consumed food. The effect did not show when the imagined food (e.g., M&M's) was not the same as the consumed food (e.g., cheese cubes) [(26); Experiment 4]. Similar sensory-specific characteristics between imagined and consumed foods are therefore fundamental for food habituation to occur. In our recent study, we found that habituation after imagined eating needs mental resources as habituation during actual eating does (28). Several studies have indicated that habituation is based on a memory process that needs cognitive capacity to occur. Hence, when individuals are distracted during eating,for example, when they watch TV during eating (29, 30), they habituate less to food and eat more. We found that a depleting task had a similar effect on habituation

after imagined food consumption. In our study, we used a mathematical counting task (31) to deplete participants prior to simulating the eating of 18 walnuts in one condition. We showed that participants in this depletion condition did not habituate to the mental simulation, and habituation was blocked, whereas they habituated in a condition without depletion.

### **EFFECTS OF MINDFULNESS ON FOOD CHOICE**

As reported above, repeatedly imagining food consumption can reduce the desire to consume the food (26). But repetitive thoughts about food consumption are not the only way to reduce the desire to consume a particular kind of food. Also important is *how* individuals think about the food. While a single vivid image of the consumption increases the influence of impulsive responses on food choice, the influence of impulsive responses on food choice decreases when consumers think about the reasons for their food choice (32). Similarly, mindful attention to thoughts about food consumption can reduce choices for unhealthy food items that are impulsively preferred by consumers. For example, Papies and colleagues (6) instructed participants to regard their thoughts from a metacognitive perspective as temporary constructions that appear and disappear. When this mindful attention was applied to food consumption, it reduced impulsive tendencies to approach food (6) and also promoted choices of healthy food (33).

### **REPEATED MENTAL SIMULATION AND MINDFULNESS AS INTERVENTIONS**

It is important to note that the effects of mindfulness are conceptually different from effects of repeated mental simulation. First, repeated mental simulation, but not mindfulness, needs repetition to show effects. Second, repeated mental simulation shows specific effects on a particular kind of food (26) but this is not the case for mindful attention (6). At present, it can be assumed that the habituation effects of repeated mental simulation reflect a memory process that leads to inhibition after some length of imagining exposure to food, whereas mindfulness might be more likely to block the tempting simulation of food consumption. Both processes are of interest for practice. Mindfulness could be used as a method for reducing unhealthy food intake. By contrast, repeatedly imagining food consumption might reduce food intake when consumption has already begun. For example, to increase habituation to a particular kind of food, individuals could think about consuming an unhealthy food that they usually prefer to eat (e.g., chocolate) repeatedly across consecutive days. However, while such long-term effects were demonstrated with exposure to real food (34), it is still a task for future research to study the long-term effects of imagined food consumption. But there is no doubt that the relevance of habituation processes is obvious if we consider recent research that has shown that overweight children habituate more slowly during consumption than non-overweight children (35). Against this background, research on repeated mental simulations could provide a promising starting point from which to advance interventions in food consumption.

### **CONCLUSION**

Current research on food intake behavior regulation is driven by a vital need to understand the successful and unsuccessful self-regulation of food consumption. Integrating the cognitive mechanisms of mental imagery and mindfulness that guide eating behaviors may be one important milestone for enhancing current models of food intake regulation. As proposed by Redden (36), a general model should include reflective (memory recall inferences,metacognitions) and perceptual (adaptation, habituation) components of satiation. He argues that satiation is partially constructed in the moment on the basis of external cues that interact with each other in a specific eating situation. Research on mental imagery and mindfulness can help us understand eating behavior and to design individual-level interventions. It can also help us understand why some individuals are more successful self-regulators than others (37).

### **REFERENCES**

behavior. *Eat Behav* (2015) **16**:5–8. doi:10.1016/j. eatbeh.2014.10.011

**Conflict of Interest Statement:** The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

*Received: 28 January 2015; accepted: 23 March 2015; published online: 07 April 2015.*

*Citation: Missbach B, Florack A and König J (2015) Mental imagery and food consumption. Front. Psychiatry 6:48. doi: 10.3389/fpsyt.2015.00048*

*This article was submitted to Affective Disorders and Psychosomatic Research, a section of the journal Frontiers in Psychiatry.*

*Copyright © 2015 Missbach, Florack and König . This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.*

## An imagery-based road map to tackle maladaptive motivation in clinical disorders

### **Jon May 1,2\*, Jackie Andrade1,2 and David J. Kavanagh2**

1 School of Psychology, Cognition Institute, Plymouth University, Plymouth, UK

2 Institute of Health and Biomedical Innovation and School of Psychology and Counselling, Queensland University of Technology, Brisbane, QLD, Australia

\*Correspondence<EMAIL_ADDRESS>
### **Edited by:**

David G. Pearson, University of Aberdeen, UK

#### **Reviewed by:**

Ian Clark, Oxford University, UK

**Keywords: transdiagnostic, therapy, treatment, cognitive, motivational, goals, addiction, craving**

### **INTRODUCTION**

There is now a widespread recognition of the importance of mental imagery in a range of clinical disorders (1). This provides the potential for a transdiagnostic route to integrate some aspects of these disorders and their treatment within a common framework. This opinion piece argues that we need to understand why imagery is such a central and recurring feature, if we are to progress theories of the origin and maintenance of disorders. This will aid us in identifying therapeutic techniques that are not simply targeting imagery as a symptom, but as a manifestation of an underlying problem.

As papers in this issue highlight,imagery is a central feature across many clinical disorders, but has been ascribed varying roles. For example, the involuntary occurrence of traumatic memories is a diagnostic criterion for PTSD (2), and it has been suggested that multisensory imagery of traumatic events normally serves a functional role in allowing the individual to reappraise the situation (3), but that this re-appraisal is disabled by extreme affective responses. In contrast to the disabling flashbacks associated with PTSD, depressed adults who experience suicidal ideation often report "flash forward" imagery related to suicidal acts (4), motivating them to self-harm. Socially anxious individuals who engage in visual imagery about giving a talk in public become more anxious and make more negative predictions about future performance than others who engage in more abstract, semantic processing of the past event (5). People with Obsessive Compulsive Disorder (OCD) frequently report imagery of past adverse events, and imagery seems to

be associated with severity (6). The content of intrusive imagery has been related to psychotic symptoms (7), including visual images of the catastrophic fears associated with paranoia and persecution. Imagery has been argued (8) to play a role in the maintenance of psychosis through negative appraisals of imagined voices, misattribution of sensations to external sources, by the induction of negative mood states that trigger voices, and through maintenance of negative schemas. In addiction and substance dependence, Elaborated Intrusion (EI) Theory (9, 10) emphasizes the causal role that imagery plays in substance use, through its role in motivating an individual to pursue goals directed toward achieving the pleasurable outcomes associated with substance use.

In this opinion piece, we would like to put forward the proposition that the motivating role that imagery plays in behavior may be a key reason for its presence in this wide range of psychopathologies, and that understanding its motivating role can help us identify common features in disorders and their treatments. It has already been recognized that the link between imagery and affect gives imagery a causative role in affective disorders (11), with the emotional amplifier hypothesis suggesting that in bipolar and anxiety disorders, statecongruent imagery leads to further affective responses, in a vicious cycle. Within EI Theory, the affective consequences of imagery are also used to explain why a cycle of elaboration follows an initial intrusive thought. The intrusive thoughts themselves are seen as the product of associative processes relating to both environmental cues and cognitions. Previous work on EI Theory focused initially on desires, and then on motivation in general. Our suggestion here moves a step further, highlighting its potential relevance to dysfunctional motivational imagery in multiple disorders.

### **ELABORATED INTRUSION THEORY**

Elaborated Intrusion Theory was initially developed to provide a cognitive account of processes involved in the maintenance of substance dependence, and to demonstrate that dependence for different substances shared a common functional basis, despite gross differences in their psychopharmacology. More provocatively, EI theory saw substance-related craving as just an extreme example of a continuum of desire, and argued that it recruited the normal cognitive processes involved in everyday desires. Since its publication ten years ago, the key premises of EI Theory and hypotheses drawn from it have been supported in a substantial body of research (10, 12–14).

According to EI Theory, environmental cues, physiological symptoms (i.e., withdrawal or deficit states), affect, and automatic or overlearned associations that operate outside of awareness do not constitute desires, because the individual is not aware of them. Instead, they generate cognitive activity that, depending upon the task context and other cognitive activity, can become sufficiently strong to become the focus of attention, and be subjectively experienced as an apparently spontaneous thought. When this thought is about a target that is strongly associated with pleasure or relief, it is highly salient, and generates a cascade of cognitive activity, which draws on further associations to elaborate the thought. Sensory imagery is often involved in the intrusion and is a key component of the elaboration, leading to anticipatory responses and augmenting its positive affective impact. However, the sensory focus also elicits an increased awareness of current deficit states, which is increasingly aversive as acquisition of the target is impeded. If the person is trying to withstand the temptation, they may also experience guilt about having the thought, or worry that it means they are losing control. While the affective consequences of the imagery lead to its continued elaboration and perpetuate the craving episode, its functional role is to motivate behavior toward satisfying the desire: it sets up a behavioral goal that competes with and can displace current goals.

### **TARGETING IMAGERY COMPONENTS**

Conceptualizing desire in this way has allowed us to devise therapeutic and behavior change techniques that target the two key components of desire: the initial intrusion and its subsequent elaboration. As the intrusion follows automatic processing of triggers external and internal to the individual, the frequency of intrusions can be reduced by either reducing those triggers or impairing their automated processing. Many existing approaches can be seen to operate through their effect upon intrusions: medications that ameliorate withdrawal symptoms are an obvious way of reducing physiological cues; mood enhancement can target the contribution of negative affect; and attentional retraining can lower an individual's preconscious processing of environmental cues associated with substance use. Once an intrusion has occurred, training in acceptance and a non-judgmental response style can help in letting the thought fade away and be displaced in focal awareness by mindful meditation or other cognitive tasks, without its elaboration dominating thought. If the thought does remain in focal awareness, a variety of imagery-based attentional control tasks can be employed to compete for imagery resources, blocking the sensory imagery of the target that maintains the elaborative cycle, shortening the duration, and weakening the affective intensity of the craving episode (12).

There are clear parallels here with the ways in which imagery is being addressed within therapeutic developments in clinical psychology. For example, imagery rescripting (15) was initially developed to help people with PTSD whose high levels of shame or guilt prevented them mentally reliving experiences, by reframing the event from the perspective of a neutral observer, weakening the emotional response. Different resolutions for the event could then be reimagined, resolving the guilt. This allows different patterns of elaboration to follow any intrusive thoughts, replacing the negative emotions associated with the original elaborations. It has since been applied to anxiety (16), eating disorders (17), and psychosis (8). Imagery-based cognitive therapy can help individuals to make the imagery more realistic (18).Within EI Theory, rescripting can be seen as an alternate elaborative strategy to a concurrent task or a modification of affective responses using mindfulness.

### **IMAGERY SUPPORTS MOTIVATION AND GOALS**

Desire does not only lead us to pursue illicit or unhealthy targets, of course: the strength of hockey players' cravings to play hockey is also determined by the vividness of the sensory imagery that they experience during the episode (19). Imagery-based desires are part of normal motivational processes, directing us toward long-term as well as short-term goals, by bridging the gap in time, and help us deal with challenges in goal acquisition. They support a wide range of behaviors beyond consumption, and EI Theory can be applied to enhance goals for positive behaviors, as well as helping people abstainfrom dysfunctional ones. Infact, a modification of motivational interviewing called Functional Imagery Training has been developed (20), where people are encouraged to form mental images of the incentives for change, the path toward that change, and their past successes in attaining similar goals. Providing a rich repertoire of vivid positive imagery associated with attainment of an otherwise abstract and general long-term goal allows that goal to compete strongly in the elaborative cycle with the pleasurable sensory images of conflicting short-term goals, which are often highly concrete and specific. By strengthening thoughts of succeeding in behavior

change, the very cues that otherwise lead to failure can be recruited to enhance success, in a positive feedback loop, with small steps toward the goal increasing the likelihood of subsequent steps being taken.

Motivation and goal fulfillment in behavior change may seem a long way from the issue of imagery within clinical disorders, but it is worth considering whether the experience of vivid mental images within psychopathologies might not also be linked to disorders of goal formation (21). Holmes et al. (11) raise this possibility in relation to bipolar disorder, arguing that vivid, positive imagery can foster creativity during hypomania but leads to pursuit of unrealistic goals during mania. The goal follows the image, as in their example of someone whose vivid image of a red sports car might prompt them to visit a car showroom. We hypothesize that the relationship between images and goals is broader, so images strengthen pursuit of existing goals as well as stimulating goal formation, and those existing goals may be goals for immediate safety or comfort rather than longer term well-being. In anxiety disorders, imagery of negative and threatening consequences sustains goals of staying safe or avoiding harm. Perhaps this can be taken further, and the flashbacks within PTSD that have been suggested as supporting re-appraisal (3) can be interpreted as part of a general problem-solving process where the individual seeks to imagine ways that they could have behaved in the traumatic situation, which could be recruited in future situations. Similarly, suicidal imagery may motivate goal directed behaviors through increasing the cognitive availability of the actions as solutions to the individual's distress (22) or it may motivate more constructive ways of achieving the imagined consequences of the actions (4). The common feature across these interpretations of imagery is that the intrusion has been triggered because an unresolved and emotionally salient problem remains unsolved. Intrusive imagery is our cognitive mechanism's way of prioritizing an unsolved problem, just as other goals stay active and intrusionprone until fulfilled (23, 24) – but if the problem cannot be resolved, the imagery becomes maladaptive, and by sustaining a dysfunctional or unachievable goal leads to an affective disorder. In depression, for

example, negative self-related ruminations displace ideas of success and lead to a cycle of anhedonia and loss of agency, with the individual finding it near impossible to imagine any future goals.

### **ROAD MAP TO TACKLE MALADAPTIVE IMAGERY**

We suggest that EI theory could provide a road map for effectively tackling imagery of maladaptive goals across clinical disorders: helping to identify risky situations for temptation and loss of control; reducing attention to intrusive thoughts through mindfulness or acceptance training; reducing the elaboration of dysfunctional desires through modality-specific interference [e.g., concurrent visuospatial tasks while recalling trauma memories (25)], or rescripting the content of the image (e.g., adjusting overly positive expectancies of substance use). Treatments targeting imagery should also consider the need to address the goals that those images support, identifying alternative, adaptive goals, and training alternative imagery to boost desire for those goals and rehearse pathways toward them, as in Functional Imagery Training (20).

This interpretation of imagery research within clinical psychology is speculative, and glosses over details and differences between the particular ways in which imagery may be critical to particular disorders. Further argument and empirical work are needed to explore the value of linking clinical conceptualizations of imagery to the rapidly developing work in cognitive psychology and behavior change. Imagery of course has a long history in clinical psychology, from systematic desensitization to covert practice, and has been extensively used to enhance sporting performance: the conceptualization of its role and application in the current paper needs to recognize and accommodate these phenomena, as well as expanding its explanatory power. Reappraising imagery as one part of a larger set of processes that act in consort to guide people in their everyday behavior raises the possibility of engaging clinically with each part of that mechanism, understanding why and how imagery is being distorted or populated by maladaptive content in different ways in a range of disorders. Understanding even part of the relationship would, we believe, justify the effort.

### **REFERENCES**

and without image rescripting. *J Behav Ther Exp Psychiatry* (2007) **38**:345–70. doi:10.1016/j.jbtep. 2007.10.006

**Conflict of Interest Statement:** The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

*Received: 04 November 2014; accepted: 26 January 2015; published online: 12 February 2015.*

*Citation: May J, Andrade J and Kavanagh DJ (2015) An imagery-based road map to tackle maladaptive motivation in clinical disorders. Front. Psychiatry 6:14. doi: 10.3389/fpsyt.2015.00014*

*This article was submitted to Affective Disorders and Psychosomatic Research, a section of the journal Frontiers in Psychiatry.*

*Copyright © 2015 May, Andrade and Kavanagh. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.*

## A role for mental imagery in the experience and reduction of food cravings

### **Eva Kemps\* and Marika Tiggemann**

School of Psychology, Flinders University, Adelaide, SA, Australia \*Correspondence<EMAIL_ADDRESS>
### **Edited by:**

David G. Pearson, University of Aberdeen, UK

#### **Reviewed by:**

Jackie Andrade, Plymouth University, UK Marianne Little, Utrecht University, Netherlands

**Keywords: mental imagery, cravings, food, craving reduction, cognitive intervention, food intake**

The term "craving" refers to a strong motivational state, which compels an individual to seek and ingest a particular substance (1). It usually refers to alcohol, tobacco, or drugs, but has become increasingly applied to food. Thus, food cravings refer to an intense desire or urge to eat a specific food (2). It is this specificity that distinguishes a craving from ordinary food choices and hunger (3). In Western societies, the most commonly craved foods are those high in fat, sugar, and salt, such as cake, chips, pizza, ice-cream, and in particular chocolate (4). Most people experience cravings for such palatable foods on occasion without any problem (5). However, food cravings can pose significant health risks for some people. Most notably, they can contribute to the development of obesity (6) and disordered eating (7),increasingly serious global health issues (8, 9). This has prompted a surge of investigations into the mechanisms that underlie the experience of food craving with a view to developing effective craving reduction techniques. The present paper focuses specifically on cravings for food, and the role of mental imagery in the experience and reduction of such cravings. For excellent reviews of the theoretical underpinnings of craving and addiction more broadly, we refer the reader to recent works by May and colleagues (10, 11). We take a more applied perspective here and critically evaluate the practical significance of imagery-based craving reduction interventions.

Over the past decade, a growing body of literature has highlighted a key role for mental imagery in the experience and reduction of food cravings. Experimental and survey data have shown that when people crave, they have vivid images of the desired food, including how delicious it looks and how good it tastes and smells (11–14). For example, when undergraduate students were asked to describe a previous food craving episode, 30% made explicit reference to mental imagery, using phrases such as "I could picture [the pizza] in my mind, picture eating it" (14). In addition, when presented with a list of descriptive statements, respondents strongly endorsed imagery-based descriptors as characteristic of their food cravings. Imagery descriptors in the visual ("I am visualizing the food"), gustatory ("I imagine the taste of the food"), and olfactory ("I imagine the smell of the food") modalities in particular were rated highly; in contrast, auditory descriptors ("I imagine the sound of myself having it") were not highly rated (12, 14). Furthermore, when asked to assign specific percentages to each of the five sensory modalities involved in an imagined food craving experience, the visual modality (39.7%) scored the highest, followed by the gustatory (30.6%) and olfactory (15.8%) modalities; by contrast, the tactile (9.5%) and auditory (4.4%) modalities were little used (14). These findings indicate that craving-related food images are predominantly visual, gustatory, and olfactory in nature.

Further evidence for the imaginal basis of food cravings comes from studies that have experimentally induced food cravings by instructing participants to imagine a food-related scenario (e.g., "Imagine you are eating your favorite food") (15). Moreover, the strength of participants'food cravings has been shown to correlate with the vividness of their appetitive images (16). In line with these empirical observations, a recent cognitive model of craving, the Elaborated Intrusion Theory of Desire (17), has placed vivid sensory images of the appetitive target at the very heart of the craving experience. According to this theory, sensory images are a key component of the cognitive elaboration that follows an initial intrusive thought about the craved substance.

More general cognitive psychological research has shown that the generation and maintenance of mental images (of whatever kind) can be disrupted by competing cognitive activities in the same sensory modality. For example, performing a visual task (e.g., watching a flickering pattern of black and white dots, termed dynamic visual noise) reduces the vividness of imagined objects or scenes, whereas engaging in a verbal task (e.g., counting aloud) reduces the vividness of imagined sounds (18). This occurs because of mutual competition between task performance and image maintenance for limited-capacity, modality-specific cognitive resources. Clinical applications of this dual-task methodology have shown that interference by a concurrent visual task can successfully reduce the vividness and emotional impact of distressing autobiographical images, characteristic of post-traumatic stress disorder (PTSD) (19–23).

Applications in the craving domain have similarly shown that competing cognitive tasks can disrupt desire-related mental images, and thereby can suppress cravings for alcohol, tobacco, and food. Notably, tasks that introduce competing information in the same sensory modality as

the imagery associated with the craving, and thus compete for the same pool of limited-capacity resources, have proven the most effective. In particular, evidence from numerous laboratory studies has shown that engaging in a range of visual tasks can reduce food cravings. For example,imagining a series of non-food scenes (e.g., a rainbow) has been shown to reduce cravings for food in general (16) and for chocolate in particular (24). Other visual tasks, such as making hand or eye movements (25, 26), watching a dynamic visual noise array (25–29), constructing shapes from modeling clay (30), and playing a game of "Tetris" (31), have also been shown to reduce food cravings.

All these tasks are thought to have their craving reducing effect by reducing the vividness of visual craving-related images. Indeed, many of the previous studies not only assessed participants' level of craving but also the vividness of their craving imagery, and reported a corresponding reduction in both measures under concurrent visual interference (25–31). However, in the absence of evidence for a causal relationship, the craving reducing effect could also reflect a reduction in the opportunity for craving imagery. In all this, it is important to note that people need not be good visualizers in general to derive benefit from imagery-based craving reduction tasks (26), thus demonstrating applicability across the board.

Although most research, to date, has focused on craving reduction via the visual sensory modality, there is evidence for a limited-capacity system that processes odor memory and imagery (32, 33) and is susceptible to olfactory interference (34, 35). Thus, the logic would suggest that a concurrent olfactory task would also reduce food cravings. In support, a number of studies have demonstrated craving reducing effects using olfactory tasks. The earliest such study showed that imagining the smell of non-food odors (e.g., eucalyptus, fresh paint) can reduce food cravings (24). More recent studies have shown that simply sniffing a non-food odorant, such as jasmine scented oil or a random chemical compound (36, 37), can also reduce food cravings.

In addition, a handful of studies has shown craving reducing effects from competing verbal tasks, such as imagining everyday sounds (e.g., a siren) (24), or listening to a foreign language recording (28). This suggests that competing tasks may act to distract participants or divert their attention. However, the craving reductions from verbal tasks in the above studies were substantially smaller than those produced by visual or olfactory tasks. Thus, although any cognitive task might serve as a distractor, it is tasks that engage the same cognitive processes as those used to construct and maintain craving-related imagery that will be most effective in reducing cravings. Further, although the great majority of people report craving-related images in the visual and olfactory/gustatory modalities (12), a minority do experience auditory images, and thus competing verbal tasks should reduce cravings for them.

All of the craving reduction studies described above have been conducted in the laboratory. These have induced food cravings experimentally using one of several methods, namely by depriving volunteers of food (30), instructing them to imagine eating a favorite food (16, 26, 27, 29), showing them pictures of food (25, 36, 37), or exposing them to actual food (24, 38). Recently, three studies have extended this laboratory work to the field. In the first, Knauper and colleagues (39) showed that a 4-day intervention whereby participants imagined themselves engaging in a favorite activity whenever they experienced a food craving reduced the intensity of naturally occurring cravings. Subsequently, Kemps and Tiggemann (40) showed that a concurrent visual task not only reduced everyday food cravings but also actual food intake. Specifically, they found that dynamic visual noise delivered on a hand-held electronic device reduced the strength of participants' food cravings over a 2-week period, as well as the likelihood that they would eat in response to craving, and consequently the amount of calories they consumed. Most recently, Hsu and colleagues (41) showed that a 1-week evaluation of a mobile app that prompted participants to imagine a visual scene whenever they experienced a snack craving reduced snack consumption. These findings demonstrate the realworld applicability of imagery-based craving reduction techniques and in particular

their utility for modifying craving-driven consumption.

One remaining limitation of the current research is that the majority of craving reduction studies in the food domain has been conducted with individuals of mostly normal weight. To date, only one study has demonstrated food craving reduction by an imagery-based technique in an overweight sample. Specifically, Kemps and colleagues (27) showed that dynamic visual noise was a more effective technique for reducing food cravings in overweight women on a prescribed weight-loss diet than was suppressing thoughts about food. This finding offers considerable scope for tackling unwanted food cravings, as experienced by individuals actively trying to lose weight (42), binge eaters (7), and some obese individuals (6).

Thus, converging evidence from numerous studies has shown that competing cognitive tasks that disrupt mental imagery can suppress food cravings. However, thus far research has shown only immediate craving reduction effects following the use of imagery-based techniques. This, of course, begs the question of the longevity of these effects. In the only study to date to investigate this question, Hamilton and colleagues (36) found that craving reduction effects from a guided imagery intervention were not sustained beyond the actual intervention. Craving levels after the intervention had reverted back to those observed at baseline. This suggests that competing cognitive tasks may disrupt craving imagery only temporarily, thereby providing momentary relief from the craving. Thus, imagery-based techniques may provide an effective "inthe-moment" tool for curbing food cravings, providing assistance in the "here and now." Nevertheless, the field studies (39– 41) suggest that imagery-based craving reduction techniques can be used successfully over the longer-term. While these techniques do not produce lasting reductions in craving, they do effectively reduce cravings on any one occasion. Moreover, their effectiveness does not diminish with repeated use. Indeed, the field studies clearly demonstrated that imagery-based techniques maintained their craving reducing effect with repeated use over several days (39), a week (41), and even over a couple of weeks (40).

Nevertheless, it is unlikely that imagerybased craving reduction techniques would be used as a stand-alone treatment. Although these techniques reliably reduce the craving, with reported reductions across studies around 20–25%, they do not eliminate it altogether. However, imagerybased techniques could be a useful adjunct to other therapeutic interventions for the treatment of craving-driven problematic eating behavior, for example, within the broader context of Cognitive Behavior Therapy. The Australian OnTrack program (www.ontrack.org.au) is an example of such an integrated treatment in the domain of alcohol dependence. Unlike other therapeutic techniques, imagery-based techniques involve very little effort on the part of the user. Visual and olfactory tasks also lend themselves for everyday use as a selfhelp tool to resist unwanted food cravings. Computerized visual tasks, such as dynamic visual noise and "Tetris," could be easily incorporated as downloadable apps on smart phones and other hand-held devices. In fact, as noted above, Hsu and colleagues (41) recently designed an app to help users combat in-the-moment snack cravings (and consumption) by prompting them to imagine a visual scene. Additionally, commercially available non-food odorants can be purchased locally and carried around in people's pockets and handbags. In this way, imagery-based craving reduction techniques can be readily accessible in a discreet manner virtually anywhere and anytime when a food craving arises.

In conclusion,increasing evidence highlights a key role for mental images in the experience of food cravings. Interference with these images from modality-specific cognitive tasks can effectively suppress such cravings, thereby paving the way for clinical interventions that target craving-driven problematic eating behavior.

### **ACKNOWLEDGMENTS**

This research was supported under the Australian Research Council's Discovery Project funding scheme (project number DP0664435).

### **REFERENCES**

1. Baker TB, Morse E, Sherman JE. The motivation to use drugs: a psychobiological analysis of urges. In: Rivers PC, editor. *The Nebraska* *Symposium on Motivation: Alcohol Use and Abuse*. Lincoln: University of Nebraska Press (1986). p. 257–323.

*Br J Health Psychol* (2005) **10**:49–56. doi:10.1348/ 135910704X14249

scanning interventions reduce food cravings. *Appetite* (2013) **71**:158–62. doi:10.1016/j.appet. 2013.08.005

**Conflict of Interest Statement:** The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

*Received: 30 October 2014; paper pending published: 24 November 2014; accepted: 16 December 2014; published online: 06 January 2015.*

*Citation: Kemps E and Tiggemann M (2015) A role for mental imagery in the experience and reduction of food cravings. Front. Psychiatry 5:193. doi: 10.3389/fpsyt.2014.00193*

*This article was submitted to Affective Disorders and Psychosomatic Research, a section of the journal Frontiers in Psychiatry.*

*Copyright © 2015 Kemps and Tiggemann. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.*

## Thinking back about a positive event: the impact of processing style on positive affect

### **Sabine Nelis 1\*, Emily A. Holmes 2,3, Rosa Palmieri 4,5, Guglielmo Bellelli 6 and Filip Raes 1**

1 Faculty of Psychology and Educational Sciences, KU Leuven – University of Leuven, Leuven, Belgium

4 Libera Università Maria Ss. Assunta (LUMSA) University, Taranto, Italy

5 EMPEA: Clinical Research Centre for Cognitive-Behavioral Psychotherapy, Bari, Italy

6 University of Bari Aldo Moro, Bari, Italy

#### **Edited by:**

Ripu D. Jindal, University of Alabama at Birmingham, USA

#### **Reviewed by:**

Jon May, Plymouth University, UK John Mace, Eastern Illinois University, USA

### **\*Correspondence:**

Sabine Nelis, Faculty of Psychology and Educational Sciences, KU Leuven, Tiensestraat 102, Box 3717, Leuven B-3000, Belgium e-mail<EMAIL_ADDRESS>The manner in which individuals recall an autobiographical positive life event has affective consequences. Two studies addressed the processing styles during positive memory recall in a non-clinical sample. Participants retrieved a positive memory, which was selfgenerated (Study 1, n = 70) or experimenter-chosen (i.e., academic achievement, Study 2, n = 159), followed by the induction of one of three processing styles (between-subjects): in Study 1, a "concrete/imagery" vs. "abstract/verbal" processing style was compared. In Study 2, a "concrete/imagery," "abstract/verbal," and "comparative/verbal" processing style were compared. The processing of a personal memory in a concrete/imagery-based way led to a larger increase in positive affect compared to abstract/verbal processing in Study 1, as well as compared to comparative/verbal thinking in Study 2. Results of Study 2 further suggest that it is making unfavorable verbal comparisons that may hinder affective benefits to positive memories (rather than general abstract/verbal processing per se). The comparative/verbal thinking style failed to lead to improvements in positive affect, and with increasing levels of depressive symptoms it had a more negative impact on change in positive affect. We found no evidence that participant's tendency to have dampening thoughts in response to positive affect in daily life contributed to the affective impact of positive memory recall. The results support the potential for current trainings in boosting positive memories and mental imagery, and underline the search for parameters that determine at times deleterious outcomes of abstract/verbal memory processing in the face of positive information.

### **Keywords: memory, processing style, positive, recall, mental imagery, abstract/verbal processing**

The regulation of positive affect and the processing of positive material are gaining attention in the context of mood disorders [e.g., Ref. (1–6)]. Depression, for instance, is not only characterized by increased negative affect but also by anhedonia, which refers to reduced positive affect or reduced pleasure in daily activities [(7), p. 160]. Besides targeting negative affect, therefore, promoting positive affect, targeting responses to positive stimuli may enhance interventions for depression [e.g., Ref. (1, 2, 8, 9)]. One specific type of positive stimuli is positive memories. In a review on blunted positivity in depression, Dunn (2) has mentioned the need for more research on positive memories. For instance, positive memories in formerly depressed individuals have decreased vividness compared to never-depressed controls (10). Further, Joormann et al. (11) showed that, whereas neverdepressed individuals are able to repair their sad mood by retrieving positive memories, this strategy is unsuccessful in formerly and currently depressed individuals. This suggests that recollection of positive memories may lead to multiple affective outcomes. Therefore, knowledge of relevant thought patterns is crucial to understand the relationship between positive memory recall and affect.

For negative stimuli, the way a negative event is processed, for instance, concrete/imagery-based vs. abstract/verbally based processing, influences subsequent affective responding [e.g., Ref. (12–14)]. A concrete/imagery-based processing style involves a situation-specific sensory processing of the event, focused on the experience of the moment (e.g., focusing on the sights and sounds). Abstract/verbal processing of a certain situation is more analytical and involves verbal thinking about the meanings, causes, and consequences or implications of an event.

More recently, research on the impact of processing styles was broadened from the domain of negative affect or situations to positive stimuli and positive memories [e.g., Ref. (5, 15, 16)]. When processing hypothetical positive situations, for instance, concrete/imagery-based processing instructions improve mood [e.g., Ref. (5, 15, 17)]. Mental imagery, therefore, is also referred to as an "emotional amplifier" [e.g., Ref. (18)]. By contrast, participants in these experiments who were instructed to think verbally (and abstractly) about positive scenarios do not show mood improvement. Moreover, it is sometimes found that verbal thoughts even lead to mood deterioration in the face of positive information (5, 15).

2 MRC Cognition and Brain Sciences Unit, Cambridge, UK

3 Department for Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden

With regard to positive memories, Bryant et al. (19) demonstrated that daily sessions of imagining positive memories increase the amount of time that individuals report to feel happy. However, this study did not include a non-imagery control for positive memories. Positive memories have also been investigated in clinical samples as a strategy to repair sad mood: Werner-Seidler and Moulds (16) demonstrated that concretely processing a joyful memory may indeed help to reduce sad feelings in (previously) depressed individuals (16). In contrast, an abstract thinking style focused on causes, meanings, and consequences as well as on making comparisons between a past happy memory and the current life did not improve sad mood in (previously) depressed persons [this was not entirely replicated when participants retrieved a self-defining memory (20)].

Interestingly, it has been proposed that not all types of abstract/verbal processing cause mood deterioration. For instance, Holmes et al. [(5); Experiment 2] showed that especially making active verbal comparisons could be responsible for mood deterioration after verbal processing instructions for positive scenarios. Thus, even in non-clinical samples, hypothetical "overly" positive situations (i.e., ones that incurred unfavorable comparisons) could be stressful in that, in your own life, events may not end up that positive. In addition to the detrimental effect of unfavorable comparisons on positive affect, we also suggest dampening as a potential moderator of the impact of abstract/verbal processing of positive events on positive affect. Interestingly, some individuals are characterized by a "*dampening response" style* to positive affect (21). Dampening is a particular cognitive response style or emotion regulation strategy, defined as "the tendency to respond to positive moods states with mental strategies to reduce the intensity and duration of the positive mood state" [(21), p. 509]. Examples of dampening thoughts in response to positive affect are: "I do not deserve this," "you know, these feelings won't last," or "thinking about those times that did not go well." Dampening can be measured by the Responses to Positive Affect questionnaire (RPA) (21, 22) and is positively associated with depressive symptoms [e.g., Ref. (23)]. Dampening can be regarded as a type of analytical thinking, in that it is characterized by a negative interpretation or evaluation of the positive situation.

In these studies, we wanted to investigate whether dampening also influences the impact of positive memory recall. From research within social psychology, it has been suggested that adopting an abstract/verbal processing mode for a positive memory (without an explicit focus on comparative thinking) can have enhancing effects (24). This may be because abstract processing can lead to positive elaborations or positive self-attributions (e.g., "I am a happy person," "I am clever") instead of interpreting the event as an isolated moment (24). However, it is plausible that if people characterized by a dampening response style think about the meaning of a positive memory, that they will less easily generate a positive meaning or may even reduce the positivity of the event. In this sense, dampening could be a potential moderator of the effect of an abstract/verbal thinking style on affect. This is akin to the idea that the impact of processing style on negative mood is conditional on individual differences in trait rumination [e.g., Ref. (25)].

In two studies, we investigated which thought processes determine the impact of positive memory recall on positive affect. In a first study, affective responding to concrete/imagery and abstract/verbal processing of a self-generated positive memory was investigated with a focus on dampening (and depressive symptoms) as moderator. In a second study, we also examined a comparative/verbal processing style.

### **STUDY 1**

We compared the affective impact of a concrete/imagery processing style focused on the sensorial and situation-specific details with an abstract/verbal processing defined as thinking about the broader meaning, causes, and consequences of an event. In addition, we investigated the moderating role of dampening.

In line with research on positive scenarios and positive memories [e.g., Ref. (5, 16)], we predicted that the processing of a positive memory in a concrete/imagery-based way would lead to increased positive affect compared to a verbal/abstract condition. With regard to an abstract/verbal processing style, we further predicted that this (immediate) change in positive affect would be smaller with increasing levels of dampening thoughts in daily life (due to minimizing or downgrading the positivity). Moreover, we did not only examine positive affect immediately after the processing of the memory but we also examined the affective impact of the processing styles after a short delay. We did this for two main reasons. First, we wanted to examine whether the processing styles would elicit a differential affective pattern after a delay. Second, we wanted to investigate the possibility that individuals characterized by higher levels of a dampening response style may still profit from positive memory recall, but only immediately. That is, it is possible that dampeners reveal an adequate initial affective response, but that the experienced positive feelings will be countered by downgrading thoughts after a delay. We predicted that these dampening thoughts would especially occur in the abstract/verbal condition, leading to a more negative affective change with increasing levels of dampening.

The study is conducted in a non-clinical sample. Given that reduced responding to positive material has been linked to depression, we also took the level of depressive symptomatology into account. Based on previous findings showing that mood improved after positive memory recall in never-depressed individuals but not in depressed individuals (11, 20), we predicted that increasing levels of depressive symptoms would be associated with worse affective outcomes.

### **METHOD**

### **PARTICIPANTS**

Seventy psychology students from the KU Leuven (University of Leuven) participated; see **Table 1** for characteristics. Written informed consent was obtained at the beginning of the study. There was no compensation for participation.

### **MEASURES**

### **Affect assessment**

Positive and negative affect were assessed using two visual analog scales, on which participants had to indicate how they felt at the moment. On the first scale, scores ranged from *totally not in a positive mood* (0) to *in a very positive mood* (100)*.* The second scale

**Table 1 | Sample characteristics, memory characteristics (VAS), and affect (VAS) per condition (Study 1)**.

BDI-II, Beck Depression Inventory-II; RPA-Dampening, the Dampening subscale of the Responses to Positive Affect questionnaire.

ranged from *totally not dejected, "down," sad, depressed* (0) to *very dejected, down, sad, depressed* (100)1 *.*

### **Responses to positive affect questionnaire**

The RPA (21) consists of 17 items scored on a 1 (*almost never*) to 4 (*almost always*) scale. Participants are requested to indicate how often they respond in a certain way when feeling happy, excited, or enthused. The RPA has three subscales: dampening (e.g., "My streak of luck is going to end soon"), self-focused positive rumination (e.g., "I am achieving everything"), and emotion-focused positive rumination (e.g., "Think about how happy you feel"). We used the 16-item Dutch version for which adequate psychometric properties are reported (22). In the current study, we focus on the 7-item dampening subscale, which had a Cronbach's alpha of 0.72.

### **Beck depression inventory – second edition**

The Beck depression inventory – second edition (BDI-II) (26) measures severity of depressive symptoms and consists of 21 fourchoice statements. Participants are asked to indicate which of the four statements best describes how they felt during the past 2 weeks. The total BDI-II score is computed by summing the 21 scores (ranging from 0 to 3), which offers a total score ranging from 0 to 63, with higher scores indicating more depressive symptoms. We used the Dutch translation by Van der Does (27). Cronbach's alpha in the present sample was 0.89.

### **Ruminative response scale (RRS) and the autobiographical memory test – minimal instructions**

The ruminative response scale (RRS) (28) assesses the tendency to ruminate when feeling sad, down, or depressed. In the

Autobiographical Memory Test (AMT)2 (29, 30), participants are given 1 min to write down a personal memory in response to 10 cue-words. The study was set up for a broader purpose than the one presented in the current paper. Consequently, the RRS and AMT are not reported in the Section "Results."

### **Memory assessment**

Three visual analog scales ranging from 0 to 100 were presented to assess the characteristics of the chosen event: (1) participants indicated that how positive they considered the event on a scale ranging from *totally not positive* to *very positive (the most positive emotional event from your life)*; (2) they rated the positive emotional intensity of the event at the moment it originally occurred on a scale ranging from *totally not emotional* to *very emotional*; (3) participants rated the positive emotional intensity that the episode had at the moment of recollection, from *totally not emotional* to *very emotional*.

### **Manipulation checks**

Before and after the induction, level of self-focus and the focus on words or images were assessed using two visual analog scales ranging from 0 to 100: (1) at this moment, my attention is *totally not focused on myself* to *very much focused on myself*; (2) at this moment the things going through my head are *mainly words* to *mainly images*.

### **PROCEDURE**

The study was presented as a study on the emotional life of university students and was conducted in a group setting. Participants were randomly allocated to one of the two conditions (abstract/verbal or concrete/imagery) via the distribution of different booklets. After giving their informed consent, participants completed a first version of the AMT. Next, participants completed the visual analog scales for negative mood, positive mood, selffocus, and focus on words or images. Participants were instructed to select a specific positive event from their own life, that is a life circumstance in which they had felt very happy and in a very positive mood. They were asked to write down a brief description of the specific episode. Next, they rated the chosen event on several characteristics (i.e., positivity, emotional intensity). This was followed by the processing style induction. In both conditions (abstract/verbal and concrete/imagery), participants were first instructed to think in the condition-specific style about their memory. Further, the processing style manipulations involved

1The anchors of all visual analog scale were 0 and 100. Unfortunately, due to photocopying, the scales were 101 instead of 100 mm. The answers were processed in centimeters and thus ranged from 0 to 10.1.

2During the AMT (written format), five positive and five negative cue words are presented in an alternating order. We used the "Minimal Instructions" version of the AMT (30). In this version, participants are asked to retrieve memories, without emphasizing in the instructions that these should be specific. At the end, participants were requested to code their memories for specificity and imagery perspective (dichotomous: first or third-person perspective). The administration of imagery perspective during the baseline AMT allowed us to investigate the relation between dampening and the use of an observer perspective during "unmanipulated" memory retrieval. For each subject, the number of observer and field memories was calculated. RPA-Dampening was positively correlated with the number of observer memories, *r*(68) = 0.37, *p* = 0.002 and negatively correlated with the number of field memories, *r*(68) = −0.32, *p* = 0.01 (*n* = 68, two persons without perspective ratings). These correlations had comparable effect sizes after control for BDI-II. The correlations were independent of the valence of the cue word.

asking five condition-specific questions, on which participants were required to focus for a duration of 1 min per question.

In the *abstract/verbal condition*, participants were given the following instructions: *Try to understand the event you described and think about the possible causes of the event, the meanings and implications of the event for you and its consequences for you. Think in words about why the episode happened as it did, about the meanings and implications of the episode for you, and the consequences of the episode for you. Consider what caused the episode and judge what it says about you. Think about the episode in words and meanings, using verbal language of the sort that you use when you speak.* Then, they were asked to answer the following five questions: "W*hy did this event happen to you?; What was the meaning of this event in your life?; What were the consequences and implications of this event for you?; What did you think of yourself after the event?; What does this event say about your personality?."* In the *concrete/imagery condition*, participants were given the following instructions: *Try to build up a detailed image of the event, as if you were reliving the event and as if a movie of the event was unfolding in your head. Spend a few moments imagining the event as if you were really there in the situation.* Then, they were asked to answer the following questions: "*What could you see around you?; What could you hear?; What could you feel, touch and experience in that situation?; What was happening around you?; What happened immediately after the event?."* The instructions and questions were framed to parallel aspects of those used by Moberly and Watkins [(13), "concrete vs. abstract"] and Holmes and Mathews [(12), " imagery vs. verbal"] as the imagery instructions appear virtually identical.

Immediately after the induction, students again completed the visual analog scales for negative mood, positive mood, self-focus, and focus on words or images. The delayed assessment of negative and positive mood was conducted after the completion of a second AMT, RRS, RPA, and BDI-II.

### **RESULTS**

### **DESCRIPTIVE STATISTICS AND GROUP COMPARISONS**

There were no differences between the two experimental conditions for any of the background variables (**Table 1**): BDI-II, *t*(68) = 0.45, *p* = 0.66, *d* = 0.11; RPA-Dampening, *t*(68) = 0.96, *p* = 0.34, *d* = 0.23; positive affect pre-induction, *t*(68) = 0.46, *p* = 0.65, *d* = 0.11; Distribution of gender was not significantly different between the two conditions, χ 2 (1) = 0.10, *p* = 0.75.

### **MEMORY CHARACTERISTICS AND CONTENT**

To exclude the possibility that condition-specific effects on affect were due to baseline differences in memory characteristics, baseline ratings of the positive memory were compared between the two conditions. There were no significant differences between conditions on the positiveness of the event, *t*(68) = 0.13, *p* = 0.90, *d* = 0.03; emotional (positive) intensity of the event when the event happened, *t*(68) = 0.11, *p* = 0.91, *d* = 0.03; and the emotional (positive) intensity of the event at the moment of retrieval, *t*(68) = 0.15, *p* = 0.89, *d* = 0.03. Means and standard deviations are depicted in **Table 1**.

With regard to the content of the memories, we categorized the memories. Forty-three participants retrieved a *social* memory, primarily related to situations with family, friends, and partners (e.g., a nice evening out with friends, a special chat, being informed about a newborn; 11 of them were related to a romantic relationship). Other memories referred to an *achievement*: a scholarly (*n* = 22) or other achievement (*n* = 2). One participant reported a memory related to the enjoyment of *nature*, and two memories could not be categorized into one of the previous categories.

### **MANIPULATION CHECKS Self-focus**

To check that self-focus did not differ as a function of condition, a repeated measures ANOVA was conducted with time (before vs. after the processing style induction) as a within-subjects factor, condition (concrete/imagery vs. abstract/verbal) as a betweensubjects factor, and self-focus as the dependent variable. The interaction between time and condition was not significant, *F*(1, 68) = 1.38, *p* = 0.24,η 2 *p* = 0.02. The main effect of time was significant, *F*(1, 68) = 6.47, *p* = 0.01,η 2 *p* = 0.09, *d* = 0.31, reflecting an increase in self-focus following the induction.

### **Processing style – imagery/verbal**

A repeated measures ANOVA was conducted with time (before vs. after the processing style induction) as a within-subjects factor, condition (concrete/imagery vs. abstract/verbal) as a between-subjects factor, and focus on words vs. focus on images as the dependent variable. There was a main effect of time, *F*(1, 68) = 17.71, *p* < 0.001,η 2 *p* = 0.21. Critically, the interaction between time and condition was significant, *F*(1, 68) = 13.35, *p* < 0.001, η 2 *p* = 0.16, which is evidence for successful inductions. There was an increase (i.e., more use of images) in the concrete/imagery condition, *t*(35) = 5.97, *p* < 0.001, *d* = 0.99, but no change on the verbal/imagery scale in the abstract/verbal condition, *t*(33) = 0.37, *p* = 0.72, *d* = 0.06.

### **Processing style – concrete/abstract**

Participants' answers were coded on the level of abstract thinking (focus on causes, meanings, and implications) and concrete thinking (focus on concrete objects, sensory details, feelings, and sensations). Each answer was rated on a scale ranging from 1 (*not at all*) to 4 (*very much*). A mean concrete and abstract score was calculated for each participant. Distribution of these ratings did not allow parametrical test due to skewed distributions. A non-parametric median test indicated that the induction was successful. The median level of abstractness was significantly higher in the abstract/verbal condition (*Median* = 3.80) than in the concrete/imagery condition (*Median* = 1.00), χ 2 (1) = 62.28, *p* < 0.001. Further, the median level of concreteness in the concrete/imagery condition (*Median* = 3.20) was significantly higher than in the abstract/verbal condition (*Median* = 1.10)*,* χ 2 (1) = 48.10, *p* < 0.001.

### **THE IMPACT OF PROCESSING STYLE, DEPRESSIVE SYMPTOMS, AND DAMPENING ON POSITIVE AFFECT**

To test if processing style (condition) influenced positive affect, and to test if RPA-Dampening or BDI-II acted as moderators of the association between processing style and positive affect, a hierarchical multiple regression analysis was conducted with change in positive affect from pre- to post-induction (positive affect after the

induction minus positive affect at baseline) as dependent variable. Centered scores were used for RPA-Dampening and BDI-II. In the first step, condition, RPA-Dampening, and BDI-II were entered. In the second step, the interaction between condition and RPA-Dampening, and the interaction between condition and BDI-II were entered. Results are depicted in **Table 2**.

Both models were significant, *p*s < 0.003. The interaction terms were both non-significant (*p*s > 0.45). To facilitate interpretation of the main effects, the first model without interaction terms was examined (*R* 2 = 0.23). Importantly, there was a main effect of condition, *B* = 0.73, *p* = 0.03. The change in positive affect was higher in the concrete/imagery than in the abstract/verbal condition.

To investigate the direction of affective change within each condition, two paired-samples *t-*tests were conducted. Within the concrete/imagery condition, as predicted, positive affect increased significantly over time, *t*(35) = 4.77, *p* < 0.001, *d* = 0.79. Positive affect did not significantly change after abstract/verbal processing, *t*(33) = 1.52, *p* = 0.14, *d* = 0.26. RPA-Dampening was a nonsignificant predictor, *B* = −0.10, *p* = 0.08. There was a main effect of BDI-II, *B* = 0.10, *p* < 0.001, such that, somewhat unexpected, higher levels of depressive symptoms were associated with higher values of affective change. So the change in positive affect from pre- to post-induction was higher in the concrete/imagery than in the abstract/verbal condition.

To investigate whether there would also be a delayed effect of processing style, the hierarchical regression analysis was repeated with the change in positive affect from post-induction to the end of the experiment as dependent variable (*n* = 69, one missing value for the last affect rating), see **Table 2**. Both models were significant, *p*s < 0.02. In the first step,*R* 2 = 0.15, there was only a main effect of BDI-II, *B* = −0.08, *p* = 0.001, which was in the opposite direction than the main effect of BDI-II in the previous analysis (i.e., the

immediate change in positive affect). The change in positive affect did not significantly differ between conditions. To investigate the direction of affective change during the delay, a paired-samples *t-*test was conducted. Positive affect decreased significantly during the delay, *t*(68) = 3.77, *p* < 0.001, *d* = 0.45, meaning that, the increased level of positive affect in the concrete/imagery condition was not fully maintained after a delay. However, positive affect at the end of the experiment was still significantly higher than at baseline in the concrete/imagery condition, *t*(34) = 2.20, *p* = 0.04, *d* = 0.37. Although positive affect slightly decreased during the delay, there was no difference between positive affect at baseline and at the end of the experiment in the abstract/verbal condition, *t*(33) = 0.65, *p* = 0.52, *d* = 0.11.

The inclusion of the interaction terms in step two added marginally significantly to the explained variance, ∆*R* 2 = 0.07, *p* = 0.059. Importantly, this second step consisted of a nonsignificant interaction between BDI-II and condition, whereas the interaction between condition and RPA-Dampening was significant, *B* = 0.23, *p* = 0.02. The interaction with RPA-Dampening revealed a significant positive relation between change in positive affect and RPA-Dampening in the concrete/imagery condition, *B* = 0.21, β = 0.53, *p* = 0.01, and not in the abstract/verbal condition, *p* = 0.72. This means that the higher trait dampening in the concrete condition, the smaller the decrease in positive affect during the delay.

### **DISCUSSION**

The affective impact of memory recall is not only determined by the valence of the event but also by how it is processed. The current study aimed to investigate the impact of concrete/imagery vs. abstract/verbal processing of recall of a positive memory on positive affect in a non-clinical sample. In addition, the role of

**Table 2 | Hierarchical regression analyses: prediction of affective change (Study 1)**.

PA2PA1 as criterion: R2 = 0.23 for Step 1, ∆R 2 = 0.02 for Step 2 (p = 0.47); PA3PA2 as criterion: R2 = 0.15 for Step 1, ∆R 2 = 0.07 for Step 2 (p = 0.06).

DV, dependent variable. PA2PA1, positive affect after the induction minus positive affect at baseline; PA3PA2, positive affect at the end of the study minus positive affect after the induction; BDI-II, Beck Depression Inventory-II; RPA-Damp, Dampening scale of the Responses to Positive Affect questionnaire (RPA). Centered scores were used. Condition, abstract condition coded as 0 and concrete condition coded as 1. Significant predictors are indicated in bold. β's indicate the regression coefficients when predictors (except condition) and the dependent variable were standardized.

\*p < 0.05.

\*\*p < 0.01.

\*\*\*p < 0.001.

dampening and depressive symptoms as potential moderators was investigated. As predicted, we found that positive memory recall in a concrete/imagery way increased positive affect. This is in line with earlier studies on imagining standardized positive scenarios [e.g., Ref. (5, 15)] and with positive memory recall to repair sad mood (16). Abstract/verbal processing did not influence positive affect in our study. This is, as a general outcome here for positive autobiographical memories, less "negative" than an actual mood deterioration (reduction in positive affect) found after verbally/abstractly processing hypothetical positive situations (5, 15). This suggests that abstract/verbal processing of a positive information may not always lead to a mood deterioration [see also Ref. (5, 20, 24)], though it does not appear to boost positive mood.

The affective impact of abstract/verbal processing was in our sample not related to people's tendency to dampen positive affect in daily life. This suggests that, the extent to which people use dampening thoughts in response to positivity (as measured via the RPA) may not influence the immediate affective impact of positive memory recall. However, the affective response to positive memory recall was higher for people with higher levels of depressive symptoms. To clarify this main effect of BDI-II, we present a group approach. In the "high BDI-II group" (=BDI-II above median), positive affect significantly increased from baseline to post-induction (*p* < 0.001, *d* = 0.81), but there was no significant change in affect in the "low-BDI-II group" (*p* = 0.13, *d* = 0.26). This means that "dysphoric" participants were more responsive to positive memory recall. This was not expected based on research that revealed a reduced responding to non-autobiographical positive pictures in people with depressive disorder [e.g., Ref. (3)] and a worsening of sad mood after positive memory recall (11). An explanation could be that "dysphoric" participants retrieved a more positive memory. However, positiveness of the event was unrelated to BDI-II, *r* = 0.01. The counterintuitive main effect of depressive symptoms might also be caused by a lower baseline state affect in dysphoric participants, and so there was more room for affective improvement. Baseline positive affect was indeed lower in the "high BDI-II group" compared to the "low BDI-II group," *p* = 0.048. The main effect of BDI-II that we observed, however, is in line with the so-called *mood-brightening effect* observed in naturalistic settings: several studies have shown that in depressed individuals and in individuals with elevated depressive symptomatology, positive events are followed by a greater decrease in negative affect (31) and a greater increase in positive affect (32) than in controls. Further research is needed to sort out the nature of this effect.

We were also interested in the delayed affective responding to memory recall. Overall, following a short delay, positive affect decreased, but still remained slightly higher than at baseline for the imagery/concrete condition. We make two notes. First,the affective change was worse for people with increasing levels of depressive symptoms. Again, to clarify this by a group approach, after the delay, the"high BDI-II"group experienced a drop in positive affect, *p* < 0.001, *d* = 0.79, while this was not the case for the "low-BDI-II group," *p* = 0.38, *d* = 0.15. This means that the increased immediate responding in people with more depressive symptoms had the downside of a greater drop after a short interval. Depressed individuals fear or suppress positive affect (33), possibly because they

want to prevent that they will experience such a drop in positive affect or that they will even feel worse afterwards. Second, on top of the main effect of BDI-II, concrete/imagery processing had a positive impact on the delayed affective response in participants with increasing levels of a dampening response style. The results suggest that after concrete memory recall, positive affect is better maintained in individuals who dampen more, which points to the importance of processing positive events in a concrete manner for "vulnerable" individuals (in this case, high trait dampeners). One possible explanation for this result is that the "dampeners" were distracted from their habitual "abstract" (dampening) responses.

Some remarks can be made about this study. First, there were no restrictions on the content of the chosen memory. Consequently, participants retrieved different types of memories, for example social or interpersonal (e.g., a nice chat with friends) or achievements (e.g., good exam results). It is plausible that meanings and consequences for social memories are generally different than for scholarly achievements. Second, there was no assessment of the temporal distance of the memory. Given that age can influence phenomenal characteristics of past events (34), it would be better to check for potential differences between conditions on memory age. Third, and critical to the next study, it has been suggested that making (unfavorable) comparisons between positive scenarios and the (less fortunate) self (5) or between a past happy event and the (less positive) current life/self might be a crucial process that undermines the benefits in positive information recall [e.g., Ref. (16)]. Therefore, an interesting next step entails the comparison of three processing styles in their affective outcome on positive memories: (1) a concrete/imagery style focused on the sensorial and situation-specific details, vs. (2) abstract/verbal processing defined as thinking about the broader meaning, causes, and consequences, vs. (3) an abstract/verbal thinking style focused on making comparisons between the current self/life and the past self/life ("comparative/verbal"). The comparison with a comparative/verbal thinking style would show whether it is a non-concrete/verbal processing style that is unbeneficial or whether it is specifically making (unfavorable) comparisons that is afforded by this processing style, which undermines positive memory recall [cf. (5)].

### **STUDY 2**

A second study was designed with three objectives: (1) to address limitations of the first study, (2) to examine a third way in which a positive memory could be processed by making verbal comparisons, and (3) to examine mental imagery perspective.

Concerning the first objective, the content variability of the memories in Study 1 was addressed by using the same memory for all participants. Passing an entrance exam is a necessary condition to study medicine or dentistry in Flanders. As a consequence, students of medicine and dentistry share this achievement. This guided retrieval also aided to control the time period of the memory (i.e., restricted to July, August, and September).

With regard to the second objective, a concrete/imagery-based processing style was generally better than an abstract/verbal processing style in Study 1. However, an abstract/verbal processing style did not significantly deteriorate affect, which was the case in some other studies with positive hypothetical scenarios [e.g., Ref. (5)]. It is hypothesized that it is especially making unfavorable comparisons with positive events that is detrimental [e.g., Ref. (5), cf. (35)]. Extending this to positive memories, past events might act as a point of comparison to evaluate one's present life (16, 36). Therefore, pleasant events could contrast with someone's less satisfactory current life, emphasizing negative aspects of the current situation or self-deterioration. Joormann and Siemer (37) and Joormann et al. (11) suggested that for depressed individuals a positive memory may highlight that one is not that positive anymore. Although the memory itself is positive, it comes to underline the discrepancy between positive times in one's past and the sad mood or the less favorable situation now [see also Ref. (16)].

We included a third processing style in which individuals compare their current self (current life) with the person they were (the life they had) at the time the positive memory was investigated (comparative/verbal). It has been suggested that especially for depressed individuals a positive memory highlights the discrepancy between the happy past moment and a sad current life, or negative current self [e.g., Ref. (11)]. We predicted that after adopting such a comparative/verbal thinking style, change in positive affect would be less beneficial, especially with increasing levels of depressive symptoms. We had no specific predictions with regard to the delayed responding. For the concrete/imagery and abstract/verbal styles, predictions are the same as in Study 1.

A third objective was to investigate the effect of processing style on imagery perspective. Episodic memory is defined by including sensory perceptual details (38, 39). That is, when remembering a specific event, people typically generate mental images. These mental images can be experienced from an observer perspective, in which people observe themselves from the outside, or from a field perspective, in which people experience the event again through their own eyes (40). What was our reasoning behind this third, perspective-related study objective? For example, research showed

that hypothetical situations, which are described at an abstract level (e.g., the broader goal of the action), are more likely to be imagined from an observer perspective than concretely described actions (41). Similar results are found if participants think about the broader meaning of a personal past event (graduation) vs. if they focus on the experience (concrete details) (42). In addition, some studies indicate that an observer perspective entails a negative evaluative component. That is, seeing oneself from the outside facilitates a negative evaluation of the self and the imagined situation, or facilitates unfavorable comparisons between the self and a positive situation (43–46) and could contribute to a negative response in the face of recalling a positive event. Bringing this together, we might expect less field (and more observer) perspective after abstract/verbal processing (as compared to concrete processing). And, observer imagery in the abstract/verbal condition could be more pronounced with increasing levels of dampening (as dampening could be regarded as negatively evaluating something positive). We also expected less field (and more observer) perspective after comparative/verbal thinking [cf. Ref. (43)].

### **METHOD**

### **PARTICIPANTS**

Participants were students of medicine and dentistry from the KU Leuven (University of Leuven). They were invited through an online university platform to participate in an online study. Participants who completed all measures were included (*n* = 159). Most participants were students of medicine (*n* = 123), 35 participants studied dentistry, and 1 participant combined both studies (see **Table 3** for characteristics). Twenty randomly selected participants received a gift voucher in exchange for participation. The study was approved by the Ethical Committee of the Faculty of Psychology and Educational Sciences, KU Leuven (University of

**Table 3 | Sample characteristics, memory characteristics, and affect (Study 2)**.

DASS-Depression, The Depression subscale of the Depression Anxiety and Stress Scale; RPA-Dampening, The Dampening subscale of the Responses to Positive Affect questionnaire. Number of sittings, how many times participants attended the entrance exam.

Leuven). Informed consent was obtained online before the start of the study.

### **MEASURES**

### **Affect assessment**

Administration of positive and negative affect was as in Study 1. However, this time, participants responded using a 9-point Likert scale (cf. internet-based nature of Study 2).

### **Responses to positive affect questionnaire – dampening subscale**

See Study 1 (21). The 7-item Dampening subscale was administered, with a Cronbach's alpha of 0.78.

### **Depression anxiety stress scale – depression subscale**

The Depression anxiety stress scale – depression subscale (DASS-D) (47) assesses the severity of depressive symptoms for the past 7 days. Item scores range from 0 (*did not apply to me at all*) to 3 (*applied to me very much or most of the time*). The basic DASS-D contains 14 items; we used the short version of the DASS-D with 7 items. The Dutch version by de Beurs et al. (48) was used. Cronbach's alpha in the present sample was 0.84. We did not use the 21-item BDI-II as in Study 1 to limit the time of the online assessment.

### **Memory characteristics**

Several Likert scales were used to assess baseline characteristics of the event or memory,and to assess memory characteristics after the induction. At baseline, participants were asked how *positive* they found the moment when they were informed that they passed the entrance exam (cf. Study 1, but, again not rated on a visual analog scale but using a 9-point Likert scale). Participants additionally rated to what extent the memory was an important and meaningful memory for them personally, using a scale ranging from *totally not important and meaningful* to *very much important and meaningful*. Post-induction, students rated to what extent passing the entrance exam was characteristic for the person they are now (this scale will not be discussed in the current paper)*.* Age of the event was assessed by determining the moment (month and year) the event took place. Finally, we assessed imagery perspective. For that, participants were first asked to make an image of the moment they were informed that they passed the entrance exam. Next, they completed two 7-point scales: the first scale ranged from (1) *totally not first person* to (7) *completely first person*; the second scale ranged from (1)*totally not third person* to (7)*completely third person* [similar scales were used in Ref. (49)].

### **Concentration**

Because of the online format, participants were asked to what extent they were able to complete the online tasks with concentration (without being distracted) on a 9-point scale ranging from *totally not* (1) to *very good* (9). Although participants are randomized to condition, we wanted to check whether individuals from the three conditions would differ on how focused they were while completing the questions.

### **PROCEDURE**

After completing the online informed consent, participants filled out a first measure of affect and self-focus (on a 9-point Likert scale). Next, they were asked to rate the positivity of a specific event, namely"the moment you were informed that you passed the entrance exam." This was followed by a rating of how important and meaningful the memory is. Next, participants were randomized to one of the three conditions. Randomization to condition was conducted automatically via the survey software Qualtrics. Processing style was manipulated using a general conditionspecific instruction followed by seven condition-specific questions. Participants had to type their answer to each question in full sentences. The induction was based on, and adapted from previous research (5, 12, 13, 15, 16, 20, 50). Unlike in Study 1, there was no time restriction per question used in the online assessment.

In the *concrete/imagery condition*, participants were prompted to focus on the moment, to replay the event in their mind as a movie, and to form a sensory mental image. Comparable to Study 1, the condition-specific questions were what they could hear, see, and what they felt when receiving their exam result, and what they did immediately after. In addition, we prompted for more details by asking how the moment unfolded, how they received the exam result (e.g., via e-mail, phone), where they were, and how bystanders behaved.

In the *abstract/verbal condition*, participants were asked to verbally generate meanings about the situation. Comparable to Study 1, they were asked what the consequences and implications were, how they thought about themselves, what the meaning was of the event for their life, and what the performance said about their capabilities. Instead of asking why the event happened to them, they were asked more specifically how they explained that they passed (succeeded in) the exam. Two extra questions assessed *why* they felt the way they did, and whether the result (performance) was as expected.

In the *comparative/verbal condition*, again, participants were asked to use verbal language. They were asked how the person they are now differs from the person they were at that moment, and how their life is different now. They were also asked how they expected their life would unfold at the time of the memory vs. how it has turned out. One question focused on a social comparison (how their performance compared to that of other students who participated in the same exam).

After the processing induction, all participants completed a second measure of affect and self-focus, followed by the assessment of how characteristic the memory is and imagery perspective. Next, we asked for demographics (such as gender and study level) and details about the entrance exam (such as time). The Dampening subscale of the RPA and the Depression scale of the DASS were completed and the study ended with a final measure of affect and an assessment of their concentration during the online study.

### **RESULTS**

### **DESCRIPTIVE STATISTICS AND GROUP COMPARISONS**

Five one-way ANOVAs showed that the conditions did not significantly differ on age, depression score (DASS-D), level of dampening (RPA-Dampening),concentration,or baseline positive affect, 0.08 < *p*s < 0.60. There were also no gender differences, χ 2 (2) = 2.06, *p* = 0.36 (for descriptive, see **Table 3**).

### **MEMORY CHARACTERISTICS**

To exclude that the effects on affect were due to baseline memory differences, several one-way ANOVAs were conducted. Conditions did not differ on the mean number of times participants sat the entrance exam, *F*(2, 156) = 0.14, *p* = 0.87, η 2 *p* = 0.002 or the level of importance/meaningfulness of the memory, *F*(2, 156) = 0.86, *p* = 0.43,η 2 *p* = 0.01. As expected, the mean positivity rate was high and no one rated the entrance exam as totally not positive. However, conditions significantly differed on how positive they perceived passing the entrance exam, *F*(2, 156) = 3.93, *p* = 0.02, η 2 *p* = 0.05. Notice that this difference cannot be driven by the processing induction as that was afterward. *Post hoc t*-tests revealed that positivity was significantly higher in the abstract/verbal compared to the comparative/verbal condition, *t*(104) = 2.87, *p* = 0.005, *d* = 0.56. Therefore, we controlled for positivity in the following regression analyses. The entrance exam took place during the year of the current research to a maximum of 4 years previously, with the exception of one participant for whom it was 6 years ago. Conditions did not differ for the age of the event, *F*(2, 156) = 1.16, *p* = 0.32,η 2 *p* = 0.02. Means and SDs are reported in **Table 3**.

### **MANIPULATION CHECKS**

### **Self-focus**

To verify if self-focus did not differ as a function of condition, a repeated measures ANOVA was conducted with time (before vs. after the processing style induction) as a withinsubjects factor, condition (concrete/imagery, abstract/verbal, comparative/verbal) as a between-subjects factor, and self-focus as the dependent variable. The interaction between time and condition was not significant, *F*(2, 156) = 0.38, *p* = 0.69,η 2 *p* = 0.005. The main effect of time was significant, *F*(1, 156) = 49.05, *p* < 0.001,η 2 *p* = 0.24, *d* = 0.56. Comparable to Study 1, self-focus increased after the processing style inductions.

### **Processing style**

To analyze responses to the questions, 21 participants per condition were randomly selected. This group (*n* = 63) was comparable to the others in terms of baseline memory characteristics and DASS-D, *p*s > 0.10, but despite the random selection, they scored lower on RPA-Dampening, *p* = 0.01. The written induction was coded in terms of level of *concreteness* (to what extent does the answer focus on sensorial information or on the concrete unfolding of the situation), *abstractness* (to what extent does the answer tell you something about meanings, causes (why they passed the exam), consequences, or why they felt the way they did), and the level of *comparative thinking* (to what extent is the answer about the person at the time of the event and the comparison with then vs. now or vs. others, the expectations then vs. how it is now, and the time in between).

We used a scale ranging from 1 (*not at all*) to 5 (*very much*). Distribution of the ratings did not allow significance tests (limited range on the scores within each condition), therefore descriptives are reported. As expected, comparative thinking was high in the comparative condition (*M* = 4.05, range 3–5), whereas there was almost no comparative thinking in the other two conditions (range 1–2). Ratings for concrete thinking were high in the concrete/imagery condition (*M* = 4.86, range 4–5), but less pronounced in the other two conditions (range 1–3). Abstract thinking was high in the abstract/verbal condition (*M* = 4.67, range 4–5), low in the concrete/imagery condition (*M* = 1.38), and somewhat represented in the comparative condition (*M* = 2.90, range 1–4). In each condition, 11 of the 21 texts were randomly selected and recoded by a second researcher. For each scale, an intraclass correlation coefficient between the score of rater 1 and rater 2 was calculated. The correlation coefficients are 0.94 for concrete thinking, 0.85 for abstract thinking, and 0.95 for comparative, suggesting a good interrater reliability.

### **THE IMPACT OF PROCESSING STYLE AND DEPRESSIVE SYMPTOMS ON POSITIVE AFFECT**

To test the impact of processing style on positive affect and to test the hypothesis that there would be an interaction of condition and depressive symptoms, we conducted a hierarchical multiple regression analysis with the change in positive affect from pre- to post-induction (positive affect after the induction minus positive affect at baseline) as the criterion variable. Because of the increased number of predictors in the second study, regression analyses were separately conducted for DASS-D and RPA-Dampening. In Step 1, positivity of the event was entered as a control variable (due to baseline differences between conditions). In Step 2, DASS-D scores, and two dummy variables to specify condition were included. The abstract/verbal condition functioned as the reference group. Finally, in Step 3, the interaction terms – which specify the interaction between condition and depressive symptoms – were entered. For DASS-D, and the positivity of the event, we used centered scores. **Table 4** summarizes the hierarchical regression analysis. For all three steps, the model was significant, *p* < 0.001. In the first step, positivity of the event was a significant predictor of change in positive affect. Next, in Step 2, the level of depressive symptoms was not a significant predictor. There was a significant main effect of condition, in such that the change in positive affect was higher in the abstract/verbal compared to the comparative/verbal condition, but the abstract/verbal and concrete/imagery condition did not significantly differ.

To know in what direction affect changed from pre- to postinduction within each condition, we conducted three pairedsamples *t*-tests. Means and SDs are depicted in **Table 3**. As predicted, in the concrete/imagery condition, positive affect significantly increased, *t*(52) = 5.45, *p* < 0.001, *d* = 0.75 (*M* = 0.70, SD = 0.93). In the abstract/verbal condition (for which the mean change did not significantly differ from the concrete/imagery condition), positive affect also significantly increased, *t*(52) = 3.73, *p* < 0.001, *d* = 0.51 (*M* = 0.53, SD = 1.03). In the comparative condition, positive affect remained unchanged after the induction, *t*(52) = 0, *d* = 0 (*M* = 0, SD = 1.09).

In the comparative/verbal condition, affective change was dependent on depressive symptoms. That is, importantly and as hypothesized, the main effect of condition was qualified by an interaction effect in the third step. The slope representing the relationship between DASS-D and affective change significantly differed between the abstract/verbal condition and the comparative/verbal condition. To interpret this interaction, we present the slope for the relation between DASS-D and affective change within

**Table 4 | Hierarchical regression analysis: prediction of affective change after processing of the positive memory (Study 2)**.

R 2 = 0.07 for Step 1, ∆R 2 = 0.06 for Step 2 (p = 0.01), ∆R 2 = 0.03 for Step 3 (p = 0.046).

PA2PA1, change in positive affect from pre- to post-induction (positive affect after the induction minus positive affect at baseline); Positivity, self-reported positivity of the event; DASS-D, Depression subscale of the Depression Anxiety Stress Scales. Centered scores were used. Dummy 1, concrete/imagery condition coded as 1, the other two conditions as 0; Dummy 2, comparative/verbal condition coded as 1, the other two conditions as 0. Significant predictors are indicated in bold. β indicates the regression coefficients when predictors (except condition) and the dependent variable were standardized.

\*p < 0.05.

\*\*p < 0.01.

\*\*\*p < 0.001.

each condition. As expected, in the comparative condition, higher DASS-D scores were associated with a lower value of the change score, *B* = −0.09, β = −0.30 *p* = 0.02, whereas the slope did not significantly differ from zero in the concrete/imagery condition, *B* = 0.03, β = 0.09, *p* = 0.51, and in the abstract/verbal condition (see **Table 4**).

### **THE IMPACT OF PROCESSING STYLE AND DAMPENING ON POSITIVE AFFECT**

The same hierarchical regression analysis as described above was conducted, however, with DASS-D score changed by RPA-Dampening. This regression analysis did, again, reveal the same main effect of condition. However, there was no main effect of RPA-Dampening, and the two interaction terms did not significantly add to the explained variance of change in positive affect (∆*R* 2 < 0.001).

### **THE DELAYED AFFECTIVE IMPACT OF PROCESSING STYLE**

The regression analyses were repeated with, as the criterion, the change in positive affect from post-induction to the end of the survey. The models with DASS-D as well as the models with RPA-Dampening were non-significant (*p*s > 0.14).

From post-induction to the end of the survey, positive affect significantly decreased in the concrete/imagery and the abstract/verbal condition (*p*s < 0.001), but not in the comparative condition (*p* = 0.08), such that in all three conditions, positive affect at the end of the survey did not differ from baseline affect, *p*s > 0.10.

### **THE IMPACT OF PROCESSING STYLE ON IMAGERY PERSPECTIVE**

Using two one-way ANOVAs, the effect of processing style (condition) on field perspective and observer perspective was examined (see **Table 3**). Conditions did not differentially influence imagery perspective, *p*s > 0.63. To inspect associations with RPA-Dampening and DASS-D, correlations were calculated within each condition. RPA-Dampening was not significantly associated with imagery perspective. With regard to the DASS-D, depressive symptoms were negatively associated with field perspective ratings in the comparative condition, *r*(53) = −0.28, *p* = 0.04, but not in the other two conditions, *r*s < −0.14, *p*s > 0.33. However, the correlation in the comparative condition did not significantly differ from the correlations in the other two conditions (*p*s > 0.41).

### **DISCUSSION**

The aim of this study was to investigate the effect of processing style manipulation of retrieval of a positive memory on positive affect (immediate and delayed) and on mental imagery perspective. Based on previous investigations, we compared three thinking styles: concrete/imagery, abstract/verbal, and comparative/verbal. We also investigated the role of self-reported dampening during daily life and current depressive symptoms as potential moderators. All participants thought back about the same achievement – an exam.

As expected, positive affect increased after concrete/imagery processing of the positive memory, replicating our Study 1, and extending results in previous related papers. However,unlike Study 1, here the abstract/verbal condition did also lead to an increase in positive affect, showing that generally abstract/verbal thinking might not be maladaptive under certain conditions. This would at least be without a focus on the comparative thinking element [cf. (5)] and for a positive content. A necessary condition to gain positive mood while generally abstract/verbal might be that the positive memory receives a strong meaning in someone's life: this was reflected in the generation of positive meanings in the abstract/verbal condition (e.g., "*it meant a lot for me," "it teaches me that with dedication you can excel in life," "it showed that I have more capacities than I thought"*).

In analogy with our results, an abstract processing style in combination with a lab-induced success experience yielded the same affective outcomes as a concrete processing style (51). This was the case for low as well as high dysphorics. Non-deleterious effects of abstract processing have also been shown in social psychology. Marigold et al. (24) hypothesized that people with low self-esteem (who tend to dampen the positivity of a partner's compliment) would profit from an abstract processing of a partner's compliment [see also Ref. (52)]. Indeed, people with low self-esteem who were prompted to verbally describe the meaning of a past compliment felt happier compared to participants who were asked to describe the isolated, concrete details of the moment they received a past compliment (24).

Unexpectedly, the immediate affective response as well as the delayed responding was independent of self-reported dampening responses during daily life, partially replicating results from Study 1. The fact that the affective response in the concrete/imagery and abstract/verbal processing conditions was independent of depressive symptoms suggests that people with higher levels of depressive symptoms are, at least under certain circumstances, able to profit from positive memory recall [e.g., when thinking back about important achievements without making (unfavorable) comparisons].

As expected, making comparisons between the current self/situation with the past self/situation in the memory was less helpful and did not increase positive mood over time. Importantly, in line with the prediction, the affective impact of making such comparisons was worse with increasing levels of depressive symptoms. It is unlikely that this is driven by a ceiling effect for individuals with higher levels of depressive symptoms, given that they started with lower positive affect at baseline. Plausibly, a general discrepancy between the current negative self or life situation and the past positive situation drives this effect. In this reasoning, we assume that especially in individuals with depressive symptoms a discrepancy between the past happy situations and the current life may exist, driving unfavorable comparisons. This discrepancy is less easily triggered while using a more concrete/imagery or abstract/verbal thinking style without explicit comparisons. The "risky" side of comparing oneself (or one's current life circumstances) with a positive event was also present in Holmes et al. (5) for hypothetical events. Our study now reveals that this also pertains to real personal positive events from the past. An implication is that if working with positive stimuli, we should take care not to get stuck in unbeneficial comparative thinking.

Importantly, passing an entrance exam is particularly related to expectations and predictions about the future university years. Therefore, making comparisons between now and then might easily prompt unachieved expectancies with regard to one's academic performances. Indeed, if we control for how satisfied participants are with how their studies unfold, the association between depressive symptoms and affect change in the comparative condition becomes marginally significant (β = −0.23, *p* = 0.085), although the interaction between condition and depressive symptoms remains significant. This suggests that the effect may also be driven by the current state of the life domain from the memory.

The three thinking styles did not differentially influence imagery perspective of the recalled event. However, in another between-subjects investigation, students who thought abstractly about their graduation were more likely to recall the memory from an observer perspective relative to students who adopted a concrete processing style (42). The induction was comparable but not identical, though, speculatively, the differential imagery measure between studies (dichotomous vs. continuous) might be a candidate explanation for the mixed results.

### **GENERAL DISCUSSION**

In two studies, we investigated the impact of processing style during positive memory recall on positive affect. We also considered the role of dampening and depressive symptoms as potential moderators.

A focus on the sensory experience of the positive event (concrete/imagery processing) improved positive affect for a positive memory that was self-generated (Study 1) and experimenterchosen (i.e., an academic achievement, Study 2). This parallels evidence with standardized positive hypothetical scenarios [e.g., Ref. (5,15)] and extends research on the concrete recall of a positive memory to repair sad mood in (previously) depressed individuals (16) to increasing positive affect in the absence of a negative mood induction in a non-clinical sample.

Results also support the development of training procedures to help make depressed individuals more specific and concrete in the retrieval of their memories [e.g., Ref. (53)] and boost their positive mental imagery of hypothetical and future events [e.g., Ref. (9, 54–56)]. It is likely that the combination of the concrete/imagery processing style with a positive content drives the increase in positive affect [for a control with a neutral or negative content, see Ref. (57, 58)].

Considering abstract/verbal processing of a memory (i.e., thinking about the broader meaning, causes, and consequences of the event), in neither of the two studies did abstract/verbal processing cause significant mood deterioration; however, it failed to lead to a beneficial effect in the controlled lab environment in Study 1. This affective outcome is thus less detrimental than contrast effects (i.e., mood deterioration) with positive memories observed in a depressed sample (11) and with hypothetical positive events in non-clinical samples (5, 15, 43). Speculatively, the different outcome for abstract/verbal processing in Study 1 and Study 2 might be driven by the content of the memory or the control over the study environment. Another possibility is that the abstract instructions in the second study were adjusted to the memory and included positive connotations (e.g., what do you think about your *performance*). This might have stimulated to derive a positive meaning. Indeed, Marigold et al. (24) confirmed that such subtle positive framework avoids self-evaluative concerns in individuals with low self-esteem.