Peering into the brain to predict behavior: Peer-reported, but not self-reported, conscientiousness links threat-related amygdala activity to future problem drinking

Abstract

Personality traits such as conscientiousness as self-reported by individuals can help predict a range of outcomes, from job performance to longevity. Asking others to rate the personality of their acquaintances often provides even better predictive power than using self-report. Here, we examine whether peer-reported personality can provide a better link between brain function, namely threat-related amygdala activity, and future health-related behavior, namely problem drinking, than self-reported personality. Using data from a sample of 377 young adult university students who were rated on five personality traits by peers, we find that higher threat-related amygdala activity to fearful facial expressions is associated with higher peer-reported, but not self-reported, conscientiousness. Moreover, higher peer-reported, but not self-reported, conscientiousness predicts lower future problem drinking more than one year later, an effect specific to men. Remarkably, relatively higher amygdala activity has an indirect effect on future drinking behavior in men, linked by peer-reported conscientiousness to lower future problem drinking. Our results provide initial evidence that the perceived conscientiousness of an individual by their peers uniquely reflects variability in a core neural mechanism supporting threat responsiveness. These novel patterns further suggest that incorporating peer-reported measures of personality into individual differences research can reveal novel predictive pathways of risk and protection for problem behaviors.

Keywords: Amygdala; Conscientiousness; Peer Reports; Personality; Problem drinking.

Figure 1. Main effects of task within the basolateral and centromedial amygdala regions of interest for the contrasts of Fearful Faces > Shapes and Angry Faces > Shapes

The contrast of Fearful Faces > Shapes resulted in significant activation within the left and right basolateral (A) and centromedial amygdala (B). The contrast of Angry Faces > Shapes resulted in significant activation within the left and right basolateral (C) and centromedial amygdala (D). All figures are thresholded at p<.05 family-wise error corrected across the volume of the region of interest.

Figure 2. Associations between amygdala activity to fearful facial expressions and peer-reported extraversion and conscientiousness

Scatterplots demonstrate associations between amygdala activity to fearful facial expressions and (A) peer-reported extraversion and (B) peer-reported conscientiousness (n=377). Mean amygdala activity represents the mean of the four sub-regions of amygdala activity examined (left and right centromedial and basolateral amygdala). Amygdala activity is mean-centered. Shaded region represents 95% confidence intervals.

Figure 3. Peer-reported, but not self-reported conscientiousness, predicts future problem drinking in men but not women

Scatterplots demonstrate associations between conscientiousness and future problem drinking behavior in men (n=78) and women (n=157). Residualized change was calculated by obtaining the residuals from a regression with AUDIT baseline scores predicting AUDIT follow-up scores. Thus, residualized change scores represent the variance in follow-up AUDIT scores not predicted by baseline AUDIT. Peer-reported conscientiousness was a significant predictor of future AUDIT scores in men, whereas self-reported conscientiousness was not.

Figure 4. Indirect effect of amygdala activity to fearful facial expressions on future problem drinking in men via peer-reported conscientiousness

The indirect effect was modeled using a multi-group model with participant sex as the grouping factor. The association between amygdala activity and peer-reported conscientiousness was constrained to be equal between men and women, given no significant moderation. The effect of peer-reported conscientiousness on AUDIT follow-up scores was freed to vary between men and women, given evidence for significant moderation. Accordingly, the indirect effect was estimated separately for men and women. 95% CI=95% bias-corrected bootstrapped confidence intervals.