Effects of approach-avoidance training on the extinction and return of fear responses

Background and Objectives
Exposure therapy for anxiety involves confronting a patient with fear-evoking stimuli, a procedure based partially on Pavlovian extinction. Exposure and other extinction-based therapies usually lead to (partial) reduction of fear symptoms, but a substantial number of patients experience a return of fear after treatment. Here we tested whether the combination of fear extinction with modification of approach-avoidance tendencies using an Approach-Avoidance Task (AAT) would result in the further reduction of conditioned fear and/or help prevent return of fear after extinction.

Methods
Two groups of participants underwent a fear acquisition procedure during which pictures of one neutral object were sometimes paired with shock (CS+), whereas pictures of another neutral object were not (CS−). The next day, in a fear extinction procedure, both objects were presented without shock. During the subsequent joystick AAT, one group primarily pulled CS+ pictures towards themselves and pushed CS− pictures away from themselves; reversed contingencies applied for the other group.

Results
Approach training was effective in modifying conditioned action tendencies, with some evidence for transfer to a different approach/avoidance task. No group differences in subjective fear or physiological arousal were found during subsequent post- training and return-of-fear testing.

Limitations
No reliable return-of-fear was observed in either group for either subjective or physiological fear measures.

Conclusions
Our results suggest that approach training may be of limited value for enhancing the short- and long-term effects of extinction-based interventions.