The influence of prior expectations on emotional face perception in adolescence.

Prior expectations influence the way incoming stimuli are processed. A standard, validated way of manipulating prior expectations is to bias participants to perceive a stimulus by instructing them to look out for this type of stimulus. Here, we investigated the influence of prior expectations on the processing of incoming stimuli (emotional faces) in adolescence. Using functional magnetic resonance imaging, we assessed activity and functional connectivity in 13 adolescents and 13 healthy adults (matched for gender and intelligence quotient), while they were presented with sequences of emotional faces (happy, fearful, or angry). A specific instruction at the start of each sequence instructed the participants to look out for fearful or angry faces in the subsequent sequence. Both groups responded more accurately and with shorter reaction times (RTs) to faces that were congruent with the instruction. For anger, this bias was lower in the adolescents (for RTs), and adults demonstrated greater activation than adolescents in the ventro-medial prefrontal cortex (vMPFC) and greater functional connectivity between the vMPFC and the thalamus when the face was congruent with the instruction. Our results demonstrate that the influence of prior expectations (in the form of an instruction) on the subsequent processing of face stimuli is still developing in the adolescent brain.