Do you remember what happened the last time you went on the Drop Tower at Canada's Wonderland, besides almost losing your lunch? How about when you went to see a suspenseful movie like Twilight? Chances are you didn't notice changes in your physiology while you were gripping the edge of your seat, but your body was probably responding with the fight or flight response.
Did You Know?
Harvard physiologist William Cannon coined the term fight or flight response in the early twentieth century. The phrase fight or flight response describes a set of automatic responses that occur in our bodies when we encounter real or perceived danger.
When something scares us, the fight or flight response takes over. Our heart beats faster, our breathing rate increases, our pupils dilate, our hair stands on end, and we may sweat more. All of these responses are due to the activity of our autonomic nervous system (ANS) . The ANS takes care of responses that we don't consciously control, such as digestion, heart rate, blood pressure, and body temperature.
There are two branches of the ANS — the sympathetic and parasympathetic nervous systems. The sympathetic nervous system is responsible for initiating the fight or flight response, whereas the parasympathetic nervous system is responsible for calming us back down and restoring homeostasis .
Did You Know?
Homeostasis is the ability of an organism to maintain internal balance by adjusting its physiological processes. Temperature, pH, and the concentrations of nutrients and wastes are examples of parameters controlled by homeostasis.
The ANS causes the fight or flight response through the action of the hypothalamus, a gland located in the fore brain that controls many brain and hormone responses. The hypothalamus stimulates the endocrine system to release the hormones adrenaline and cortisol from the adrenal gland into the blood stream, which causes the changes in our body when we're startled.
It seems like our bodies do a lot of work just because a movie or ride frightens us. After all, we're not in any real danger! However, the response evolved in our ancestors to enable survival and when we're in real danger, it will kick in and allow you to deal with what you're facing, be it a hungry polar bear or an intruder.
Did You Know?
Stories about mothers committing superhuman feats like lifting cars off their children may be true. These actions are possible due to an adrenaline rush as a result of the fight or flight response.
Thrill Seekers vs. Risk Avoiders
Why do some people seem hardwired to go skydiving or base-jumping, whereas other people would rather stay home and curl up with a book? It may have to do with their ability to regulate dopamine , a neurotransmitter associated with rewards and motivation. Thrill seekers tend to have fewer of the receptors that pick up excess dopamine, whereas risk avoiders tend to have more.
Did You Know?
: A neurotransmitter is a chemical messenger used by brain cells, or neurons, to communicate with other cells.
Is Love of a Thrill in Our Genes?
Although many genes are involved in human behaviour, the D4 dopamine receptor gene appears to be longer in thrill-seekers. The COMT gene , which reduces the effect of dopamine on the brain, is also important for predicting thrill-seeking behaviour. Individuals who like excitement have a different variant of the COMT gene than more timid people.
Next time you watch a horror movie, check your pulse. How are your palms? If they get sweaty, the horror flick is doing its job, but you might want to wait a minute before grabbing some more popcorn, or that cute guy's hand.
Sapolsky, Robert M. (1994) Why Zebras Don't Get Ulcers — A Guide to Stress, Stress-Related Diseases, and Coping. W. H. Freeman and Company, New York, U.S.A.
Widmaier, Eric P., Raff, Hershel, and Strang, Kevin T. (2004) Vander, Shreman, and Luciano's Human Physiology: The Mechanisms of Body Function, 9th ed. McGraw-Hill Higher Education, Toronto, Canada.
Experts Find 'Scaredy-Cat' Gene, BBC News Health, Aug. 11, 2008.
Horror Haters Could Share the Same Gene, Metro, Aug. 10, 2008.
Evidence of "Risk-Taking" Brain, BBC News Health, Dec. 31, 2008
Angier, Natalie. Variant Gene Tied to Love of New Thrills, NY Times, Jan. 2, 1996.
Candace Webb received her Ph.D. in molecular biology from the University of Ottawa in 2006, but now researches plant circadian rhythms at UCLA. When not working, she spends her time writing, hiking, biking, painting, and hanging out at the beach.