Deleting "fear" from "fear extinction": Estimating the individual extinction rate via non-aversive conditioning.

Individual differences in extinction learning have attracted ample attention of researchers and are under investigation as a marker for the onset of anxiety disorders and treatment response. Unfortunately, the common paradigm for obtaining the extinction rate, which entails aversive stimulus pairings, is subject to practical limitations. Therefore, the present study assessed whether the use of an aversive stimulus is actually needed to get a good estimate of the extinction rate. A total of 161 undergraduate students completed a conditioning task with both an aversive and a non-aversive stimulus. Using latent class growth analysis (LCGA), distinct trajectories, representing normal and stunted extinction learning, were identified for both these stimulus types. Participants' membership in these classes largely overlapped for aversive and non-aversive stimulus pairings and respective extinction indices were significantly correlated. Thereby, findings suggest that the use of a non-aversive stimulus could suffice for successfully capturing individual differences in extinction learning. However, future studies are needed to confirm that conditioning with a non-aversive stimulus may serve to predict clinically relevant outcomes.