A yawn often sets off a chain reaction. Those who observe a yawn will repeat the action shortly afterward. In fact, simply thinking about yawning will cause a person to yawn.
Yawning Is a Fixed Action Pattern in Humans
Observing a yawn or merely reading about a yawn can trigger the fixed action pattern of yawning. It is a behavior that must be carried to completion. In his article, "Contagious yawning and infant imitation," published in the Bulletin of the Psychonomic Society in 1989, Robert R. Provine of the Department of Psychology at the University of Maryland points out that yawning is difficult to stifle and difficult to stop.
Fixed action patterns are innate responses that are not influenced or changed by the environment. For example, a spider will spin the same web no matter where it is located. This is not a learned behavior, but a genetically-programmed behavior. It is instinct.
Greylag Goose and Round Objects
The Greylag goose is most commonly found in Europe and Asia. A mother goose will return an egg to the nest after it rolls out. She does this by extending her neck toward the egg, placing the bottom of her bill on the egg, and pulling it back to the nest. If the egg does not reach the nest, she will repeat the entire sequence of events.
Any round objects outside of the nest will initiate the fixed action pattern for the mother goose. According to Robert J. Brooker, et al., ethologists report that "this stimulus acts on the goose's central nervous system, which provides a neural stimulus to initiate the motor program." This is called a fixed action pattern.
Male Sticklebacks
Male sticklebacks are fish that are characterized by their red bellies. Their fixed action pattern is in response to the red bellies of other fish. When they observe another fish with a red belly, they will attack it. This is how they protect their territories from other male sticklebacks.
Niko Tinbergen tested this fixed action pattern by exposing male sticklebacks to models that did not necessarily look like fish, but had red undersides. The male sticklebacks attacked every model with the red, but ignored the lifelike model with no red underside.
Fixed action patterns are innate and are not learned. They are behaviors that cannot be controlled, or are very difficult to influence, such as yawning. In fact, anyone who reads this article is likely to yawn before completing it, and is likely to continue to yawn until directing attention to another subject.
Reference
Brooker, Robert J., Widmaier, Eric P., Graham, Linda E., and Stiling, Peter D. Biology. New York: McGraw-Hill, 2008.
Diane Ursu - Diane Ursu joined Suite101 as a contributing writer in August 2009 and became a Feature Writer in January 2010. She is a freelance writer ...
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