Folk explanations of behavior: a specialized use of a domain-general mechanism

Abstract

People typically explain others' behaviors by attributing them to the beliefs and motives of an unobservable mind. Although such attributional inferences are critical for understanding the social world, it is unclear whether they rely on processes distinct from those used to understand the nonsocial world. In the present study, we used functional MRI to identify brain regions associated with making attributions about social and nonsocial situations. Attributions in both domains activated a common set of brain regions, and individual differences in the domain-specific recruitment of one of these regions--the dorsomedial prefrontal cortex (DMPFC)--correlated with attributional accuracy in each domain. Overall, however, the DMPFC showed greater activation for attributions about social than about nonsocial situations, and this selective response to the social domain was greatest in participants who reported the highest levels of social expertise. We conclude that folk explanations of behavior are an expert use of a domain-general cognitive ability.

Keywords: causality; neuroimaging; open materials; semantic memory; social cognition; theory of mind.

Figure 1

Design of the Social/Nonsocial Why/How Task. Each block is formed by pairing a yes/no question that is either attributional (Why) or factual (How) with 9 target photographs. In an independent sample of respondents, 5 photographs in every block elicited a consensus response of ‘yes’, while the remaining 4 elicited a consensus response of ‘no’. Participants have 2500 ms to respond to each photograph. Once the participant responds, the task advances. Given this, block durations were contingent on response times. However, total task duration was not, as block onsets were fixed. Finally, between each photograph is a brief reminder of the question for that block. The diagram below displays the first two trials of an attribution block for each of the three stimulus categories. The same photographs were used to create the factual question blocks. See Table 1 for a list of all questions.

Figure 2

Region of interest (ROI) and whole-brain analyses. (a) Percent signal change (PSC) from fixation baseline in the independently defined regions of interest (ROIs; see Table S3 for details). Test results for all ROIs are provided in Tables S4-S5. (b) Whole-brain analysis showing regions independently associated with evaluating attributions versus facts for all three stimulus categories. (c) Whole-brain analysis showing the region of the dorsomedial prefrontal cortex (DMPFC) that displayed an elevated response to attributions about both emotions and actions when compared to attributions about nonsocial situations. For both whole-brain analyses, regions were identified from a group-level (N = 19) search using a cluster-forming threshold of p < .001 and a cluster-level family-wise error rate of 0.05. Activity is overlaid on the group mean anatomical at a threshold of p < .005 to show extent. VMPFC = Ventromedial Prefrontal Cortex; LOFC = Lateral Orbitofrontal Cortex; aSTS = Anterior Superior Temporal Sulcus; TPJ = Temporoparietal Junction.