The role of learning in threat imminence and defensive behaviors

Life threatening situations as urgent as defending against a predator precludes the use of slow trial and error strategies. Natural selection has led to the evolution of a behavioral system that has three critical elements. (1) When it is activated it limits the behaviors available to the organism to a set of prewired responses that have proven over phylogeny to be effective at defense. (2) A rapid learning system, called Pavlovian fear conditioning, that has the ability to immediately identify threats and promote prewired defensive behaviors. (3) That learning system has the ability to integrate several informational dimensions to determine threat imminence and this allows the organism to match the most effective defensive behavior to the current situation. The adaptive significance of conscious experiential states is also considered.