Human emotional expression and the peripersonal margin of safety

The brain evolved to give special representation to the space immediately around the body. One of the most obvious adaptive uses of that peripersonal space is self-protection. It is a safety buffer zone, and intrusions can trigger a suite of protective behaviours. Perhaps less obvious is the possible relationship between that complex protective mechanism and social signalling. Standing tall, cringing, power poses and handshakes, even coquettish tilts of the head that expose the neck, may all relate in some manner to that safety buffer, signalling to others that one’s protective mechanisms are heightened (when anxious) or reduced (when confident). Here I propose that some of our most fundamental human emotional expressions such as smiling, laughing, and crying may also have a specific evolutionary relationship to the buffer zone around the body, deriving ultimately from the reflexive actions that protect us.