The conditioning and extinction of fear in youths: What's sex got to do with it?

•We examine sex differences in fear conditioning and extinction tasks in youths.•An own-sex effect was observed in physiological responses (SCRs) during conditioning.•Male faces triggered greater fear ratings during conditioning and extinction.•All participants showed resistance to fear extinction in fear ratings.•Resistance to fear extinction was observed for SCRs in boys viewing male faces. Adult work shows differences in emotional processing influenced by sexes of both the viewer and expresser of facial expressions. We investigated this in 120 healthy youths (57 boys; 10–17 years old) randomly assigned to fear conditioning and extinction tasks using either neutral male or female faces as the conditioned threat and safety cues, and a fearful face paired with a shrieking scream as the unconditioned stimulus. Fear ratings and skin conductance responses (SCRs) were assessed. Male faces triggered increased fear ratings in all participants during conditioning and extinction. Greater differential SCRs were observed in boys viewing male faces and in girls viewing female faces during conditioning. During extinction, differential SCR findings remained significant in boys viewing male faces. Our findings demonstrate how sex of participant and sex of target interact to shape fear responses in youths, and how the type of measure may lead to distinct profiles of fear responses.