Differential UCS expectancy bias in spider fearful individuals: evidence toward an association between spiders and disgust-relevant outcomes.

Recently, differential UCS expectancies were found for high- and low-predatory fear-relevant animals [Davey, G. C. L., Cavanagh, K., & Lamb, A. (2003). Differential aversive outcome expectancies for high- and low-predation fear-relevant animals. Journal of Behavior Therapy and Experimental Psychiatry, 34, 117-128]. The present study extends these findings to spider phobia. In a hypothetical experiment, high (n = 27) and low (n = 28) spider fearful individuals estimated the probability that slides of spiders, maggots, pit bull terriers, or rabbits would be followed by a sip of nauseating juice, a shock, or nothing. Maggots were selectively associated with the disgusting juice, pit bull terriers with the harm-related shock, and rabbits with nothing. Spiders were associated with both aversive UCSs, but significantly stronger in the high fear group. Additionally, an expectancy bias toward disgust-relevant consequences was the single best predictor of spider fear. These findings imply that in accordance with the disease-avoidance model, expectations of disgust-relevant consequences are involved in spider phobia.