Surviving in a Potentially Dangerous Environment

Chapter 19 focuses on avoidance behavior. The chapter begins by introducing two types of avoidance behaviors. Active avoidance refers to behaviors that avoid or prevent an aversive stimulus, and passive avoidance refers to the suppression of behaviors associated with an aversive stimulus. It then describes a procedure known as discriminated avoidance in which a conditioned stimulus signals the presence of an aversive stimulus. The chapter then delves into the two-process theory of avoidance, which states that avoidance includes both classical and operant conditioning, and the classic procedure used to test the hypothesis. The chapter explains the triadic design, which led to a concept proposed by psychologist Martin Seligman, learned helplessness. It then describes how avoidance signals do not always occur and that animals and people can learn to avoid an aversive stimulus without an explicit warning stimulus. The chapter concludes with a description of Michael Fanselow’s predatory defense continuum, which describes the stages of species-specific defense reactions (SSDRs): pre-encounter defensive behavior, post-encounter defense behavior, and circa strike defensive behaviors.