Renewal of instrumental avoidance in humans

Avoidance behaviour is a hallmark of anxiety disorders and OCD, yet there is a pressing need to understand how extinction of avoidance responses proceeds and what variables if any determine recovery from extinction. In this study, we used a within-subjects design in which participants learned to avoid a loud noise signalled by two discrete visual stimuli (CSs+), by pressing the space bar in the computer keyboard. We trained each CS+ along with a CS- in a different context. During extinction, CSs+ and CSs- stimuli were presented in the alternative context from that of training , and participants were allowed to freely respond, but no loud noise was presented. Finally, all CSs were tested in both contexts, resulting in a within-subjects ABA vs ABB comparison. Participants increased avoidance responses over training, and decreased responding during extinction. During test, responding was significantly higher when CS+ stimuli were tested in the training vs the extinction context, thus showing renewal of instrumental avoidance in humans. Additional analyses revealed substantial individual differences in this task. This study shows renewal of instrumental avoidance in humans, and the design can shed light on ways of making extinction more durable.