The medial prefrontal cortex (mPFC) reliably activates in social cognition tasks, among others (for reviews, see Amodio and Frith,
2006; Lieberman,
2007). However, in a dramatic reversal of this now-standard effect, our prior study documents the standard mPFC activation to photographs of people
only from social groups that elicit exclusively social emotions (e.g. pity, envy), but dramatically reduced mPFC to social groups that elicit non-exclusively social emotions (e.g. disgust) (Harris and Fiske,
2006); these results occur when viewers think about the emotion these people evoke. Because of its role in social cognition, reduced mPFC activity may suggest that people belonging to these latter extreme outgroups may be perceived differently, maybe even as less human.
1Work on schema-triggered affect suggests that some type of affective response accompanies person perception (Fiske and Pavelchak,
1986). Emotion researchers often differentiate between complex emotions that occur later in cognitive development, and more basic emotions that may be considered hard-wired into our affective repertoire (Barrett,
2006; Niedenthal
et al.,
2006). Similar to this distinction, one can argue that some emotions, referred to as
exclusively social emotions, occur only in the actual, imagined or implied presence of other people, while
non-exclusively social emotions can occur either in the presence of people or objects. For instance, people do not report feeling envy toward a desired object such as a sports car; rather they report feeling envy toward the owner of the sports car. As for the car itself, they may actually report liking it. Thus, what separates exclusively social emotions from non-exclusively social emotions is the necessary requirement that people, human beings, be present for the former, not the latter, to occur.
Two fundamental dimensions of social perception are perceived trait warmth and competence (Fiske
et al., in press). The Stereotype Content Model (SCM; Fiske
et al.,
2002) predicts that perceived trait warmth and competence interact to differentiate affective reactions to members of distinct social groups (). In a two-dimensional space of four quadrants, social groups perceived as high in both competence and warmth evoke from perceivers the ingroup social emotion of pride; groups perceived as high in competence but low in warmth receive the ambivalent social emotion of envy; groups perceived as high in warmth, but low in competence receive the paternalistic social emotion of pity. However, outgroups perceived as low in both warmth and competence elicit disgust, an emotion that is not exclusively social, being directed both at people and objects that seem repellant (Rozin and Fallon,
1987). Perceiving low–low outgroups as ‘disgusting’ suggests that people perceive these groups as so strikingly different that they do not evoke an exclusively social emotion.
2 Infrahumanization theory (Leyens
et al.,
2001,
2003) states that people see some groups as less human than others; they judge
outgroups themselves as not experiencing complex emotions to the same extent that the ingroup does. From the perceiver's own experience of emotion, SCM studies (Fiske
et al.,
2002; Cuddy
et al., in press), including the initial neuro-imaging study (Harris and Fiske,
2006) suggest that extreme outgroups also do not elicit these complex, exclusively social emotions
in the perceiver.
If groups do not elicit an exclusively social emotion, can they also be individuated to the same extent as other social group actors? The Continuum Model of Impression Formation (CM; Fiske and Neuberg,
1990; Fiske
et al.,
1999) provides a theoretical backdrop within social psychology for person perception. According to this model, social perception occurs along a continuum from more categorical to more individuated impressions. When perceivers encounter social group members, they see them initially in terms of master statuses (age, race and gender in US samples; Fiske,
1998) that activate cognitive (stereotypic) and affective (prejudiced) responses. But motivated and informed perceivers can move along the continuum to form more nuanced, individuated impressions. The type of information that allows a more nuanced impression includes the person's idiosyncrasies: personality, accomplishments, skills and preferences (likes and dislikes). Particular judgments of preferences, for instance, may force one to go beyond the perceived social category to draw on information perceived to be unique to that social group member and experience an exclusively social emotion. Therefore, if perceivers initially consider individuating information when encountering an outgroup member who elicits a non-exclusively social emotion, they may activate mPFC where they did not before.
Additionally, inferring another's preferences causes perceivers to mentalize, that is, to consider what is inside another's mind. This type of mentalizing usually requires: observing behavior (buying broccoli), knowing the social consensus about the behavior (most people buy broccoli), knowing the actor's consistency (buying broccoli on every supermarket visit) and knowing the actor's distinctiveness in that behavior
3 (always broccoli, never turnips; Kelley,
1972; McArthur,
1972). However, in social perception, this information is often not readily available. Thus, to judge preference, one must infer most of this information. Common sources of this inference include the behavior of the target's social group (stereotypes; Fiske
et al.,
1999) or even one's own behavior (simulation; Heal,
1996). Similarity to stereotypes or simulation could act as a proxy for the individual, which then allows the inference.
Recent behavioral work within social psychology suggests that similarity, inferring what is in another's mind and other dimensions significantly predict the degree to which outgroup members elicit the disgust emotion (Harris and Fiske, unpublished data). In two studies, participants first described a day in the life of a pictured social group member (only Study 1) before rating the person on a variety of dimensions derived from social neuroscience tasks that activated the mPFC (both studies). Results indicated that social group members who elicit disgust are perceived as less warm, competent, intelligent, articulate, similar and familiar. Further, participants reported more difficulty inferring what was in their heads, more difficulty inferring their dispositions, and the targets as experiencing more ups and downs in life—compared with social group members who elicited more social emotions (Harris and Fiske, unpublished data). This evidence, together with the social neuroscience evidence already mentioned, suggests a number of dimensions that may underlie the reduced mPFC activity observed in the initial neuro-imaging study.
Social neuroscience supports at least two of these dimensions in activating the mPFC. Work on similarity of the actor to the self provides an example (Mitchell
et al.,
2005). In one such paradigm, participants either decided how symmetrical a target's face appeared, or how pleased the target felt about having the picture taken. The correlation between the mPFC activity and similarity occurred only in this latter mentalizing task, suggesting that self-reflection indeed may be used as a proxy for the information about the target. This imaging work also implicitly posits a ventral–dorsal distinction for respectively similar–dissimilar social stimuli (Mitchell
et al.,
2005).
The role of inferred preferences in changing affective (prejudiced) neural signatures to outgroups also finds support in social neuroscience paradigms. For instance, faces of Black men can evoke a stronger amygdala and insula response in White participants than ingroup faces (Hart
et al.,
2000; Lieberman
et al.,
2005; Phelps
et al.,
2000; Wheeler and Fiske,
2005). This activation correlates with implicit measures of fear and prejudice, such as respectively the startle eye-blink response and the Implicit Association Test (IAT; Phelps
et al.,
2000; see also Amodio
et al., (
2003), for a similar correlation with event-related potentials). However, inferring the vegetable preference of the pictured Black man eliminates this differential amygdala and insula activation (Wheeler and Fiske,
2005). Thus, inferring preferences either affects the perceptual experience of the Black face or instantaneously recruits cognitive mechanisms that regulate the amygdala and insula activations, reducing these sub-cortical signatures of the prejudiced response. Similar processes may also occur for higher cortical areas.
In sum, the task of inferring preferences should re-activate the mPFC for social group members who otherwise elicit non-exclusively social emotions (e.g. disgust) for two reasons. First, the inference may depend on simulation scaled to similarity, indirectly suggesting social emotion elicitation. And second, even if self-generated, this information about another's preferences moves one further along the continuum to individuated impressions—reserved primarily for social targets who elicit exclusively social emotions and themselves reliably activate the mPFC. Therefore, we make two predictions: (i) significantly less mPFC activity to social group members who elicit non-exclusively social emotions, compared with those group members who elicit exclusively social emotions (a replication of the previous finding), and (ii) significantly more activity in the mPFC for (vegetable) preference judgments than for categorical (age) judgments.