Pupil response: a psychophysiological measure of fear during analogue desensitization.

15 highly aroused snake phobics individually constructed fear hierarchies by selecting colored photographs of snakes. Subjects either imagined fear scenes based on their photographs or were exposed to duplicate projected slides during desensitization. Pupillary responses of the Slide Group were also recorded before, during, and after desensitization. Fear of snakes was significantly reduced for both groups within five or fewer desensitization sessions. Changes in pupil size of the Slide Group appear to reflect arousal of fear as well as reduction of fear after treatment. Current technology makes pupillary response a viable psychophysiological measure of fear.