Biological Bases of Social Behavior (8C) Practice Test

In a virtual “audience” paradigm, participants deliver a short speech while seeing either (i) one neutral face or (ii) a grid of 12 neutral faces. Afterward, participants complete a startle reflex task while viewing brief images of neutral crowds. Those who spoke to the 12-face audience show larger startle responses to crowd images and report greater anticipatory worry about future group settings. Which brain region activity would be expected as described?

A lab recruits adolescents who report persistent fear of negative evaluation in classrooms. Saliva samples are collected for genotyping, and participants complete a standardized social-evaluation task: giving a short speech to two unfamiliar judges who maintain neutral expressions. Those carrying a specific allele show higher avoidance (longer pauses, fewer words) only when they also report a history of chronic peer rejection; without that environmental history, carriers do not differ from non-carriers. Which biological process is most consistent with the observed pattern of social behavior?