Symbolic or derived generalization of fear and avoidance in humans: A systematic review

Fear and avoidance responses acquired in the presence of one event often generalize to other symbolically related cues or events, increasing the range of potential threatening stimuli capable of evoking defensive responses. In this way, symbolic or derived generalization of fear or avoidance occurs when physically dissimilar, arbitrary stimuli come to occasion conditioned fear or avoidance responses without further training. Despite being a well-studied domain of obvious translational and clinical relevance, a systematic review of this literature has not yet been conducted. We systematically searched Web of Science and PsycINFO databases for empirical articles on the symbolic generalization of fear and avoidance in humans. Following screening, 31 articles were identified that described studies conducted with a wide range of variables and procedures, relatively small samples sizes, and often lacking justification for participant recruitment and the use of task mastery criteria. We conclude by discussing how research on the symbolic generalization of fear and avoidance in humans can provide a valid and reliable contextual behavioral model for studying and treating anxiety related disorders.