4. Discussion
PHYSIOLOGICAL STRESS
The objective of this study was to determine to what extent mental activation of one’s pet dog reduces stress reactivity to a social-evaluative or cognitive stressor. Results suggested that participants who wrote and thought about their pet dog prior to an experimental stressor reported less of a decrease in positive affect from before to after the stressor compared to participants who wrote and thought about a general positive memory. However, this study found that mental activation conditions did not differ in the magnitude of change in other subjective stress measures (negative affect, negative self-evaluation) or physiological stress (SBP, DBP, HR). The impact of mental activation of a pet dog on stress reactivity was also not dependent on the type of stressor received (social-evaluative or cognitive). Findings from the current study differ from those of Zilcha-Mano and colleagues, who found that mental activation of one’s pet dog reduced subsequent cardiovascular reactivity during a stressor [Previous studies have found that mentally activating internal representations of a supportive human relationship can attenuate physiological stress reactivity during a stressor [Results lend evidence towards the possibility that the physical presence of a dog may be required to elicit a significant stress-reducing effect. Indeed, several studies have found significant stress-buffering effects of dog presence via reduced heart rate [Our second hypothesis, which stated that the stress-buffering effect of thinking about one’s pet dog would be more pronounced among individuals randomized to completing a social-evaluative stressor than those completing a cognitive stressor, was not supported. While we did find that participants who received the social-evaluative stressor had significantly larger increases in SBP compared to the cognitive stressor, there were no significant interactions between time, stressor condition, and memory condition. Therefore, the two stressors resulted in similar increases in cardiovascular stress reactivity regardless of the type of memory condition. It is important to note that although the TSST is described as a social stressor in the literature, it contains cognitive (i.e., mental arithmetic) components completed in a social-evaluative manner. In addition, the cognitive stressor may have contained a small social component given that the experimenter was required to correct the participant in response to an error. This overlap in the nature of the stressors may explain why an effect of stressor type was not found. It is possible that if we had chosen a purely social stressor task such as social exclusion, the pet dog condition may have been more impactful, e.g., [