Fear

Abstract

Abstract Fear is the multimodal state that accompanies the anticipation of an imminent or predictable aversive outcome. This state promotes adaptive autonomic, behavioral, and cognitive responses such as avoidance, escape, and learning. Fear is essential to animal species’ survival, and as such is highly conserved, with the emergence of basic fear learning and responding dating back at least 700 million years. The adaptive significance of fear reflects its effects not only on physiology and behavior, but also on social outcomes. Across a wide range of species, fear can be socially communicated via visual, auditory, and chemical signals, which promote avoidance of threat and social learning in observers. In some social species, the communication of fear can also benefit expressers by inhibiting aggression and eliciting care from observers. This chapter reviews the evolutionary functions and neural circuitry of fear and its autonomic, behavioral, and communicative features.