'Like me?': ventromedial prefrontal cortex is sensitive to both personal relevance and self-similarity during social comparisons

Abstract

Social comparisons are an important means by which we gain information about the self, but little is known about the neural mechanisms underlying comparative social judgment, as most prior functional magnetic resonance imaging research on this topic has investigated judgments of self or others in isolation. Ventromedial prefrontal cortex (vmPFC) has routinely been implicated in social cognitive tasks that rely on such absolute judgments about the self or others, but it is unclear whether activity in this region is modulated by personal relevance of social stimuli or self-similarity of judgment targets. Using functional magnetic resonance imaging, we demonstrate that these forces interact to determine vmPFC response during social comparisons, as well as neural activity in the bilateral anterior insulae. Comparisons between the self and similar others exhibit a unique response in this region when compared with other judgment contexts, suggesting that the special psychological status afforded to these social comparisons is indexed by activity in the vmPFC and insula.

Keywords: insula; pACC; self; social comparison; vmPFC.

Fig. 1

Diagram illustrating (A) experimental paradigm, (B) experimental design and (C) mean reaction time for each comparison condition.

Fig. 2

BOLD activity associated with comparative social judgment in the ventromedial prefrontal cortex (vmPFC; specifically, perigenual anterior cingulate cortex) and anterior insula, displayed on composite image of participants’ T1-weighted anatomical scans. Warm: interaction between personal involvement and similarity of comparator (Talairach coordinates, [4 33 6], k = 78, P < 0.05, FWE), F(1,72) = 14.97. Cool: Conjunction of (YS > YD), (YS > SS) and (YS > SD) demonstrating activity unique to comparisons between the self and a similar peer (Talairach coordinates, [−3 36 3], k = 40, t(18) = 4.05).

Fig. 3

Parameter estimates extracted from ventromedial prefrontal cortex (vmPFC; A) and anterior insula (aIns; B) from clusters in Figure 2 for each comparison condition. Parameter estimates for (B) are from the right anterior insula cluster, but an identical pattern was reflected by parameter estimates extracted from left anterior insula as well. *P < 0.01, **P < 0.005, ***P < 0.00001. YS = You vs Similar, YD = You vs Different, SS = Similar vs Similar, SD = Similar vs Different.