Reinstatement of conditioned responses in human differential fear conditioning.

The present study aimed at investigating reinstatement of conditioned responding in human classical conditioning using a differential fear conditioning paradigm. Reinstatement is defined as the return of extinguished conditioned responses due to the experience of one or more unexpected USs. As expected the reinstatement group showed reinstatement of US-expectancy while a similar return of conditioned responses was not present in the control group. In the fear ratings a similar pattern was observed. In addition, and in line with previous findings, we found that the more negative the CS+ remained after extinction, the more return of conditioned responding was observed. Clinical implications and suggestions for further research are discussed.