How to Measure Fear Generalization? Reliability and Validity of Commonly Used Indices

The ability to adaptively transfer acquired fear to novel situations is fundamental for survival in ever-changing environments and may contribute to the emergence and persistence of anxiety disorders. Consequently, research has focused on the assessment of fear generalization profiles to predict individual differences in trait anxiousness. However, substantial heterogeneity in the measurement and operationalization of generalization hampers comparisons across studies and poses a risk to the replicability of findings. To address these issues, we reviewed the literature to identify commonly used methods for characterizing fear generalization profiles. We then conducted simulation analyses to examine correlations between indices and probe their robustness against measurement noise. Finally, we used two large empirical datasets (N = 1,175 and N = 256) to examine the reliability of these indices and their validity in predicting psychopathology. All identified indices were substantially correlated but highly sensitive to measurement noise, with only minimal differences between methods. Reliabilities were moderate for subjective ratings but poor for skin conductance responses. All indices of fear generalization were unrelated to individual levels of anxiousness. Overall, a more comprehensive discussion of conceptual and methodological issues is needed to better understand how fear generalization contributes to the etiology and maintenance of anxiety disorders.