464 v. AFFECTI vE PROCESSES
tions such as love, gratitude, and compassion 
on a daily basis (Impett et al., 2010). When 
people make personally costly sacrifices in 
intimate relationships for approach-  related 
goals, they experience greater positive emo -
tion (Impett et al., 2010). People who ap -
proach intimate relations with a bias toward 
approach enjoy the emotional delights and 
rewards of sex to a greater extent (Impett et 
al., 2010).
More complex appraisal biases that de -
rive from discrete emotion and compo -
nential theories should predict individual 
differences in emotional response as well. 
For example, a bias to perceive unfairness 
in actions at work predicts increased anger 
and frustration (e.g., Matta, Erol-  Korkmaz, 
Johnson, & Bicaksiz, 2014). Appraisal bias -
es related to perceiving oneself as efficacious 
predict increased guilt but not shame (Pas -
sanisi, Sapienza, Budello, & Giaimo, 2015). 
Other, more complex appraisal biases— 
toward certainty, perceived effort, legitima -
cy, normativeness—  are also likely to influ -
ence individual differences in emotion and 
await empirical investigation.
Shifting to a higher level of analysis, 
culture-  level appraisal biases have been pos -
ited as one mechanism leading to individual 
differences in emotional responding that, 
when aggregated, produce culturally modal 
personalities (Scherer & Brosch, 2009). And 
more recently, emotion scientists have turned 
to the study of beliefs about emotional expe -
rience, which one might think of as meta- 
appraisals (Ford, Lwi, Hankin, Gentzler, & 
Mauss, 2018; Ford & Gross, 2019). Do we 
value happiness and positive emotion, even 
excessively (Ford, Mauss, & Gruber, 2015; 
Gruber, Mauss, & Tamir, 2011)? Do we 
believe emotions are controllable? To what 
extent do we believe emotions are transient? 
Are we accepting of emotional experiences, 
particularly negative emotions? These be -
liefs about emotion have powerful effects 
and are certain to contribute to individual 
differences in emotional experience (Ford et 
al., 2015).
Genetic Influences and  Neurotransmission
Our understanding of the neural mecha -
nisms of emotion is still very young but 
growing rapidly. At a broad, structural level, research using functional neuroim -
aging is slowly unpacking the roles of the 
amygdala, nucleus accumbens, anterior 
cingulate cortex, and orbitofrontal cortex, 
among other structures, in our responses to 
emotional stimuli (Kringelbach & Berridge, 
2017; Phan, Wager, Taylor, & Liberzon, 
2002). Although studies attempting to local -
ize specific emotions in the activity of single 
brain structures have generally failed (e.g., 
Lindquist et al., 2012), newer, multivariate 
statistical approaches document distinct 
patterns or networks of brain activity as -
sociated with distinct or “discrete” emotion 
states (Kragel & LaBar, 2016; Saarimäki 
et al., 2015; Vytal & Hamann, 2010). Re -
searchers are exploring at the cellular and 
molecular levels the roles of dopamine, se -
rotonin, the endogenous opioids, oxytocin, 
and other key neurotransmitters in emotion -
al processes as well (e.g., Domes et al., 2007; 
Kringelbach & Berridge, 2017; Nelson & 
Panksepp, 1998; Outhred et al., 2013). The 
precise psychological processes mediated by 
any given structure or neurotransmitter are 
still very much under debate, and increasing -
ly the evidence points to complex networks 
of activity rather than single structures sup -
porting most activities of the human mind. 
However, research linking individual differ -
ences in emotional experience and behavior 
to variability in neural activity is not only 
feasible, but also can help contribute to our 
understanding of how the brain supports 
human emotional responding.
The human brain is an excellent example 
of a universal structure, characterized by 
species-  typical mechanisms supporting spe -
cific aspects of sensation, cognition, experi -
ence, and behavior that nonetheless show 
tremendous variability in action from person 
to person. These variations are closely tied 
to individual differences in emotion (Ha -
mann & Canli, 2004). Those high in trait 
anxiety show more intense activity in the 
amygdala—  a structure activated during the 
perception of emotional stimuli, particularly 
threatening stimuli—  in responses to others’ 
facial expressions of fear, even when those 
images are presented subliminally (Etkin et 
al., 2004). Attachment-  anxious individu -
als show heightened activity in the anterior 
cingulate and insular cortices, which are 
also active during the experience of physi -