The relationship between Intolerance of Uncertainty and conditioned fear acquisition: Evidence from a large sample

Despite being considered a valid model for the etiology of anxiety disorders, the fear conditioning paradigm does not always show clear correlations with anxious personality traits that constitute risk factors for the development of anxiety disorders. This may in part due to error variance and the fact that fear conditioning studies are typically underpowered to investigate inter-individual differences. In the current study, we focus on the relationship between conditioned fear acquisition and Intolerance of Uncertainty (IU). In a re-analysis of a large previous study (N = 120), which was conducted using a healthy student sample and a partial reinforcement procedure (75%) with words as Conditioned Stimuli (CSs), the relationship between IU and several outcome measures (i.e., fear ratings, expectancy ratings, skin conductance responses, and startle responses) during fear acquisition was examined. We find that IU is positively related to fear ratings towards the CS+ (r = 0.29), even when controlling for the shared variance with trait anxiety. Furthermore, we find a subtle relationship between IU and startle responses to the CS- (r = -0.23), though this correlation did not survive correction for the shared variance with trait anxiety. Taken together, we replicate some of the correlations previously reported in the literature. However, we recommend that future studies employ even larger samples and more advanced statistical techniques such as structural equation modelling to investigate the correlations between fear acquisition indices and anxious traits in a fine-grained manner.