Avoidance of learnt fear: Models, potential mechanisms, and future directions.

Avoiding stimuli that were previously associated with threat is essential for adaptive functioning, but excessive avoidance that persists in the absence of threat can turn dysfunctional and results in severe impairments. Fear and avoidance conditioning models have substantially contributed to the understanding of safety behaviors towards learnt fear stimuli. Safety behaviors are executed in the presence of a feared stimulus to prevent the upcoming threat and are well-established in laboratory models. Avoidance of learnt fear, i.e., avoidance of the feared stimulus itself, is typically initiated before the onset of a feared stimulus: individuals oftentimes avoid fear stimuli to prevent negative emotions evoked by them or ultimately the associated threat. Avoidance of learnt fear is surprisingly understudied despite its prevalence in pathological anxiety. The current overview proposes potential behavioral mechanisms and neural circuits of avoidance of learnt fear in humans, and discusses findings and paradigms suitable for examining it. Specifically, higher-order conditioning, decision making paradigms, and context-cue conditioning investigate distinct forms of avoidance of learnt fear. We also discuss the clinical prospects and future directions of research in avoidance of learnt fear.