Fear and Loathing in Elmhurst Burst

March 7, 2010

I am recovering from laughter. This evening my roommate was cleaning the bathroom and she thought that I had gone to bed, but I called out to her and she nearly jumped three feet into the air. Her fear made me laugh so hard that I nearly wet myself! Although I did think to myself, instead of laughing I could have been nursing a fat lip – what if her response to fear was to punch me in the face? So, today’s question is: what are the common responses to fear?

A:
The purpose of fear is to promote survival and fear response is almost entirely automatic. Fear is created as a chain reaction in the brain. It begins with a stressful stimulus and ends with the release of chemicals that cause the physiological changes in the body triggering the fight-or-flight response.

There are two paths involved in the fear response: The low road is quick and messy, while the high road takes more time and delivers a more precise interpretation of events. Both processes are happening simultaneously. The high road is much more thoughtful. While the low road is initiating the fear response just in case, the high road is considering all of the options.

The physiological responses can be:

• heart rate and blood pressure increase
• pupils dilate to take in as much light as possible
• veins in skin constrict to send more blood to major muscle groups (responsible for the "chill" sometimes associated with fear -- less blood in the skin to keep it warm)
• blood-glucose level increases
• muscles tense up, energized by adrenaline and glucose (responsible for goose bumps -- when tiny muscles attached to each hair on surface of skin tense up, the hairs are forced upright, pulling skin with them)
• smooth muscle relaxes in order to allow more oxygen into the lungs
• nonessential systems (like digestion and immune system) shut down to allow more energy for emergency functions
• trouble focusing on small tasks (brain is directed to focus only on big picture in order to determine where threat is coming from)

All of these physical responses are intended to help you survive a dangerous situation by preparing you to either run for your life or fight for your life - thus the term "fight or flight".

Sources:

How Stuff Works: Fear

Wikipedia: Fear