Secondary extinction reduces reinstatement of threat expectancy and conditioned skin conductance responses in human fear conditioning.

Background And Objectives: Secondary extinction refers to the phenomenon that extinction of one conditioned stimulus (CS) results in the reduction of conditioned responses for other CSs conditioned with the same unconditioned stimulus (US). Previous research with rats has demonstrated that secondary extinction can interfere with the return of conditioned fear after a reinstatement manipulation. Here we investigated this phenomenon in two pre-registered studies in humans.