Contingency awareness and fear conditioning: A comprehensive examination of associated factors

A long-standing debate in the psychology of learning and memory is whether contingency awareness—explicit recognition of the relationship between conditioned stimuli and unconditioned stimuli—is a prerequisite for fear acquisition in humans. In an extensive participant pool (N = 895), we systematically investigated the impact of manipulating core experimental parameters and individual differences that may moderate contingency awareness. Key parameters included the presence of online expectancy or fear ratings, engagement in concurrent tasks, sensory modalities of conditioned stimuli and unconditioned stimuli, and type of instruction. These manipulations strongly influenced the proportion of participants who acquired contingency awareness, ranging between 47% and 96%, with only aware participants exhibiting conditioned responses. We confirm that contingency awareness is necessary for human fear conditioning and highlight the parameters that experimenters can use to ensure learning. Individual differences in age, personality traits, and working memory capacity did not contribute to the probability of becoming contingency aware.