Fear, disgust, and information processing in specific phobia: the application of signal detection theory

A growing body of research suggests that individuals with small animal and blood-injection-injury (BII) phobias respond to phobia-relevant stimuli with a combination of fear and disgust. Despite the recognition that disgust may serve a functional role in phobic avoidance behavior, little is known about biased information processing for disgust-related material. Two studies examined recognition memory, using signal detection analyses, for phobia-relevant and general disgust pictures. Study I failed to find differences between spider phobics, BII phobics, and nonphobics in discrimination ability (d') and response bias (c) for spider, surgical, and two categories of general disgust pictures. Results indicated that all participants responded in a liberal manner toward surgical and disgust pictures, whereas they responded more conservatively when judging spider pictures. Study 2 also failed to find differences between BII phobics and nonphobics in discrimination ability and response bias for surgical and disgust pictures presented at 500 and 50 ms exposure durations. All participants again adopted a liberal response bias toward surgical and disgust pictures, although only under the 500 ms stimulus presentation condition. These results do not suggest the presence of preferential information processing of phobia-relevant or general disgust elicitors among phobic participants. The functional value of disgust-mediated information processing biases is questioned given the available literature. Implications and suggestions for continued information processing research for fearful and disgusting stimuli in specific phobia are outlined.