Johanna M. Jarcho

Background Violence exacts staggering personal and financial costs – a burden disproportionally born by adolescents and young adults. This may be partially due to an increased sensitivity to social rejection during this critical phase of development. Irritability, a transdiagnostic symptom, is often elicited by social interactions. Yet, little is known about age differences in social rejection‐elicited aggression and irritability. Progress toward testing such relations has been hindered by a lack of ecologically‐valid tasks that enable the measurement of in‐the‐moment social rejection‐elicited aggression. Methods In this paper, we describe an initial study of young adults ( n = 55) that demonstrates the efficacy of a novel Virtual School and Aggression Paradigm (VS‐AP). Next, we replicate these results in a second study of adolescents and young adults (ages 11–25 years; n = 173) and examine relations between social rejection‐elicited aggression, irritability, and age. Results We found that aggressive behavior in the VS‐AP differed for accepting, rejecting, and unpredictable peer types (Study 1: F (2, 108) = 20.57, p < .001, ε 2 = .28; Study 2: F (2, 344) = 152.13, p < .001, ε 2 = .47), demonstrating that the VS‐AP successfully models social rejection‐elicited aggression. In Study 2, age was negatively correlated with aggressive behavior ( r = −.29, p < .001) and irritability ( r = −.28, p < .001), while irritability was positively correlated with aggressive behavior ( r = .28, p < .001). Age moderated the relation between social rejection‐elicited aggression and irritability. Specifically, irritability was more predictive of aggression in young adults than in adolescents ( F (3, 167) = 7.07, p < .001). Conclusions Data suggest mechanisms promoting rejection‐elicited aggression may differ across development and vary for those with and without high levels of irritability. The VS‐AP is a promising tool for probing neurocognitive, developmental, and clinically relevant mechanisms underlying social rejection‐elicited aggression.