Consider this stressful situation: At a meeting for which you have thoroughly prepared, the chair criticizes you and accuses you of failing to attend to tasks that were, in reality, someone else’s responsibility. As all eyes turn on you, you feel your face getting hot, your jaw tightening, and your fist clenching. You would not shout or hit anyone—doing so would only make things worse. But you feel like shouting or striking out.
Now consider another stressful situation: You walk into class a few moments late, only to find everyone putting books and notes away—apparently preparing for a test you did not realize had been scheduled for today. Your heart seems to stop, your mouth is dry, your knees feel weak and you momentarily consider hurrying back out the door. Your life is not really in danger, and running away will not solve your problem—so why should you feel a physical urge to escape?
These two scenarios illustrate the two poles of the fight-or-flight response, a sequence of internal processes that prepares the aroused organism for struggle or escape. It is triggered when we interpret a situation as threatening. The resulting response depends on how the organism has learned to deal with threat, as well as on an innate fight-or-flight “program” built into the brain.
The learned fight response
Evidence that the fight response can be learned is seen, for example, in studies showing that reactions to a perceived insult are strongly dependent on culture. In the United States the learned fight response has been nurtured in the “culture of honor” that developed in the South—which some experts believe may account for the southern states’ much higher murder rate in comparison to the northern states.(1) Learning can also affect our internal responses to stress. For example, in a study of patients with high blood pressure (which can be a stress response), those who took placebos along with their medication for high blood pressure maintained a healthy blood pressure after the medication was removed, as long as they continued taking the placebo.(1)(2) This suggests that their expectation that the placebos would control their blood pressure was enough to reduce the emergency response of the blood vessels.
While the fight or flight response clearly can be learned, it also involves an innate reaction that operates largely outside consciousness. This was first recognized in the 1920s by physiologist Walter Canon, whose research showed that a threat stimulates a sequence of activities in an organism’s nerves and glands. We now know that the hypothalamus controls this response by initiating a cascade of events in the autonomic nervous system (ANS), in the endocrine system and in the immune system.(4)
As you will recall, the autonomic nervous system regulates the activities of our internal organs. When we perceive a situation as threatening, this judgment causes the hypothalamus to send an emergency message to the ANS, which sets in motion several bodily reactions to stress. This response is helpful when you need to escape a hungry bear or confront a hostile rival.
4. Jansen, A. S. P., Nguyen, X. V., Karpitskiy, V., Mettenleiter, T. C., & Loewy, A. D. (1995, October 27). “Central command neurons of the sympathetic nervous system: Basis of the fight-or-flight response.”Science,270, 644 -646.