An experimental study of the role of vulnerability related perceptions in spider fear: comparing an imaginal and in vivo encounter.

The effect of manipulating perceptions of the uncontrollability, unpredictability and dangerousness of a spider was assessed using both an imaginal and in vivo task involving an encounter with a spider. Participants were randomly assigned to one of eight conditions formed by the crossing of factors. Experimental manipulations of uncontrollability, unpredictability and dangerousness all had a significant effect on Task Related Spider Fear in the in vivo exposure task. Results indicated a greater effect on task related fear for in vivo exposure (R(2)=.258) compared to imaginal exposure (R(2)=.053). Perceptions of spiders as uncontrollable, unpredictable and dangerous accounted for much of the variance in spider fear beyond that accounted for by the experimental manipulations. The idea that perceptions of spiders as uncontrollable, unpredictable and dangerous are causally related to spider fear was supported with in vivo exposure being a stronger modality for fear modification than imaginal exposure.