Your Body’s Fight or Flight Response System

 Ever had the hairs on the back of your neck “stand up” while watching a scary movie or when you walk into a freezing cold room in only a t-shirt?

Almost everyone has gotten goose bumps at one point in their life or another, but what exactly are they and why do we get them?

Goose bumps are caused by your body’s nervous system and are part of the body’s “fight or flight” system meaning that, like microexpressions, they are completely involuntary.  They are caused by tightening muscles, which pull body hair into an erect position.

They occur mainly for two reasons: 1. when it’s cold and 2. when someone experiences the emotion of fear.

In animals that have fur, individual hairs on end (“standing up”) in cold weather is a sensible course of action, since the erect hairs can trap air, adding a layer of insulation to protect the animal from the cold.

In the case of fear, goose bumps in an animal with fur causes the animal to look larger, potentially intimidating the predator which is threatening it, giving the animal a chance to run or fight.

In humans, these bumps are a vestigial reflex, left over from a time when humans had more hair; a wide variety of animals demonstrate this interesting reflex in response to certain stimuli.

Remember that emotions are transient, bio-psycho-social reactions to events that have consequences for our welfare and potentially require immediate action (Matsumoto, Frank and Hwang: Nonverbal Communication: Science and Applications).

So next time you get goose bumps, just remember they are a biological, involuntary reaction that is elicited by your body.