Fight-or-flight response

The fight-or-flight response (also called the fight-or-flight-or-freeze response, hyperarousal, or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival.^[1] It was first described by Walter Bradford Cannon.^[a]^[2] His theory states that animals react to threats with a general discharge of the sympathetic nervous system, priming the animal for fighting or fleeing.^[3] More specifically, the adrenal medulla produces a hormonal cascade that results in the secretion of catecholamines, especially.^[4]

This response is recognized as the first stage of a general adaptation syndrome that regulates stress responses among vertebrates and other organisms.^[5]

Physiology

Autonomic nervous system

The autonomic nervous system is a control system that acts largely unconsciously and regulates heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. This system is the primary mechanism in control of the flight-or-fight response and its role is mediated by two different components.^[6]

Sympathetic nervous system

The sympathetic nervous system originates in the spinal cord and its main function is to activate the physiological changes that occur during the fight or flight response. This component of the autonomic nervous system utilizes and activates the release of norepinephrine in the reaction.^[7]

Parasympathetic nervous system

The parasympathetic nervous system originates in the spinal cord and medulla and works in concert with the sympathetic nervous system. Its main function is to activate the "rest and digest" response and return the body to homeostasis after the fight or flight response. This system utilizes and activates the release of the neurotransmitter acetylcholine.^[7]

Reaction

The reaction begins in the amygdala, which triggers a neural response in the hypothalamus. The initial reaction is followed by activation of the pituitary gland and secretion of the hormone ACTH.^[8] The adrenal gland is activated almost simultaneously and releases the neurotransmitter epinephrine. The release of chemical messengers results in the production of the hormone cortisol, which increases blood pressure, blood sugar, and suppresses the immune system.^[9] The initial response and subsequent reactions are triggered in an effort to create a boost of energy. This boost of energy is activated by epinephrine binding to liver cells and the subsequent production of glucose.^[10] Additionally, the circulation of cortisol functions to turn fatty acids into available energy, which prepares muscles throughout the body for response.^[11] Catecholamine hormones, such as adrenaline (epinephrine) or noradrenaline (norepinephrine), facilitate immediate physical reactions associated with a preparation for violent muscular action. These include the following:^[12]

Acceleration of heart and lung action
Paling or flushing, or alternating between both
Inhibition of stomach and upper-intestinal action to the point where digestion slows down or stops
General effect on the sphincters of the body
Constriction of blood vessels in many parts of the body
Liberation of metabolic energy sources (particularly fat and glycogen) for muscular action
Dilation of blood vessels for muscles
Inhibition of the lacrimal gland (responsible for tear production) and salivation
Dilation of pupil (mydriasis)
Relaxation of bladder
Inhibition of erection
Auditory exclusion (loss of hearing)
Tunnel vision (loss of peripheral vision)
Disinhibition of spinal reflexes
Shaking

Function of physiological changes

The physiological changes that occur during the fight or flight response are activated in order to give the body increased strength and speed in anticipation of fighting or running. Some of the specific physiological changes and their functions include:^[13]^[14]

Increased blood flow to the muscles activated by diverting blood flow from other parts of the body.
Increased blood pressure, heart rate, blood sugars, and fats in order to supply the body with extra energy.
The blood clotting function of the body speeds up in order to prevent excessive blood loss in the event of an injury sustained during the response.
Increased muscle tension in order to provide the body with extra speed and strength.
The pupils dilate to help see with increased clarity.
Increased perspiration to prevent over-heating due to the increased metabolic rate.

Evolutionary perspective

An evolutionary psychology explanation is that early humans had to react to threatening stimuli quickly and did not have time to psychologically and physically prepare themselves. The fight or flight response provided prehistoric humans with the mechanisms to rapidly respond to threats against survival.^[15]^[16]

Examples

A typical example of the stress response is a grazing zebra. If the zebra sees a lion closing in for the kill, the stress response is activated. The escape requires intense muscular effort, supported by all of the body’s systems. The sympathetic nervous system’s activation provides for these needs. A similar example involving fight is of a cat about to be attacked by a dog. The cat shows accelerated heartbeat, piloerection (hair standing on end, normally for conservation of heat), and pupil dilation, all signs of sympathetic arousal.^[12] Note that the zebra and cat still maintain homeostasis in all states.

Varieties of responses

Animals respond to threats in many complex ways. Rats, for instance, try to escape when threatened, but will fight when cornered. Some animals stand perfectly still so that predators will not see them. Many animals freeze or play dead when touched in the hope that the predator will lose interest.

Other animals have alternative self-protection methods. Some species of cold-blooded animals change color swiftly, to camouflage themselves.^[17] These responses are triggered by the sympathetic nervous system, but, in order to fit the model of fight or flight, the idea of flight must be broadened to include escaping capture either in a physical or sensory way. Thus, flight can be disappearing to another location or just disappearing in place. And often both fight and flight are combined in a given situation.

The fight or flight actions also have polarity – the individual can either fight or flee against something that is threatening, such as a hungry lion, or fight for or fly towards something that is needed, such as the safety of the shore from a raging river.

A threat from another animal does not always result in immediate fight or flight. There may be a period of heightened awareness, during which each animal interprets behavioral signals from the other. Signs such as paling, piloerection, immobility, sounds, and body language communicate the status and intentions of each animal. There may be a sort of negotiation, after which fight or flight may ensue, but which might also result in playing, mating, or nothing at all. An example of this is kittens playing: each kitten shows the signs of sympathetic arousal, but they never inflict real damage.

Males and females tend to deal with stressful situations differently. Males are more likely to respond to an emergency situation with aggression (fight), while females are more likely to flee (flight), turn to others for help, or attempt to defuse the situation – 'tend and befriend'. During stressful times, a mother is especially likely to show protective responses toward her offspring and affiliate with others for shared social responses to a threat.^[18]

In current times, these responses persist, but fight and flight responses have assumed a wider range of behaviors. For example, the fight response may be manifested in angry, argumentative behavior, and the flight response may be manifested through social withdrawal, substance abuse, and even television viewing.^[19]

Emotional components

Emotion regulation

In the context of the fight or flight response, emotional regulation is used to proactively avoid threats of stress or to control the level of emotional arousal.^[20]^[21]

Emotional reactivity

During the reaction, the intensity of emotion that is brought on by the stimulus will also determine the nature and intensity of the behavioral response.^[22] Individuals with higher levels of emotional reactivity may be prone to anxiety and aggression, which illustrates the implications of appropriate emotional reaction in the fight or flight response.^[23]^[24]

Cognitive components

Content specificity

The specific components of cognitions in the fight or flight response seem to be largely negative. These negative cognitions may be characterized by: attention to negative stimuli, the perception of ambiguous situations as negative, and the recurrence of recalling negative words.^[25] There are also may be specific negative thoughts associated with emotions commonly seen in the reaction.^[26]

Perception of control

Perceived control relates to an individual's thoughts about control over situations and events.^[27] Perceived control should be differentiated from actual control because an individual's beliefs about their abilities may not reflect their actual abilities. Therefore, overestimation or underestimation of perceived control can lead to anxiety and aggression.^[28]

Social information processing

The social information processing model proposes a variety of factors that determine behavior in the context of social situations and preexisting thoughts.^[29] The attribution of hostility, especially in ambiguous situations, seems to be one of the most important cognitive factors associated with the fight or flight response because of its implications towards aggression.^[30]

Negative effects of the stress response in humans

The stress response temporarily suppresses various biological processes such as sexual responses and digestive mechanisms. This is in an effort to focus on the stressor situation. While the fight or flight response is an adaptive reaction, prolonged increases in stress can cause a variety of negative physiological and psychological negative effects, including:^[31]

Physiological effects

Psychological effects

Anxiety
Restlessness
Lack of motivation or focus
Irritability or anger
Depression

Behavioral effects

Prolonged stress responses may result in chronic suppression of the immune system, leaving the body open to infections. However, there is a short boost of the immune system shortly after the fight or flight response has been activated. This may have filled an ancient need to fight the infections in a wound that one may have received during interaction with a predator.

Stress responses are sometimes a result of mental disorders such as post-traumatic stress disorder, in which the individual shows a stress response when remembering a past trauma, and panic disorder, in which the stress response is activated by the catastrophic misinterpretations of bodily sensations.

For potential positive meanings, reference can be made to Hans Selye's psychological concept of eustress or good, healthy stress.

Notes

^ Some references say he first described the response in 1914 in The American Journal of Physiology. Others in the 1915 edition of Bodily Changes in Pain, Hunger, Fear and Rage. Other sources say that he first used the term in 1929 or in 1932 edition of the same book. The issue needs further research.

References

^ Cannon, Walter (1932). Wisdom of the Body. United States: W.W. Norton & Company. ISBN 0393002055.
^ Walter Bradford Cannon (1929). Bodily changes in pain, hunger, fear, and rage. New York: Appleton-Century-Crofts.
^ Jansen, A (27). "Central Command Neurons of the Sympathetic Nervous System: Basis of the Fight-or-Flight Response". Science Magazine. 5236 (270). {{cite journal}}: Check date values in: |date= and |year= / |date= mismatch (help); Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
^ Walter Bradford Cannon (1915). Bodily Changes in Pain, Hunger, Fear and Rage: An Account of Recent Researches into the Function of Emotional Excitement. Appleton-Century-Crofts. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)
^ Gozhenko, A (2009). PATHOLOGY - Theory. Medical Student's Library. Radom. pp. 270–275. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Schmidt, A; Thews, G (1989). "Autonomic Nervous System". In Janig, W (ed.). Human Physiology (2 ed.). New York, NY: Springer-Verlag. pp. 333–370.{{cite book}}: CS1 maint: multiple names: authors list (link)
^ ^a ^b Chudler, Eric. "Neuroscience For Kids". University of Washington. Retrieved 19 April 2013.
^ Margioris, Andrew (2011). "ACTH Action on the Adrenal". Endotext.org. Retrieved 18 April 2013. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
^ Padgett, David (2003). "How stress influences the immune response". Trends in Immunology. 24 (8): 444–448. doi:10.1016/S1471-4906(03)00173-X. PMID 12909458. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
^ King, Michael. "PATHWAYS: GLYCOGEN & GLUCOSE". Washington University, St. Louis.
^ "HOW CELLS COMMUNICATE DURING THE FIGHT OR FLIGHT RESPONSE". University of Utah. Retrieved 18 April 2013.
^ ^a ^b Henry Gleitman, Alan J. Fridlund and Daniel Reisberg (2004). Psychology (6 ed.). W. W. Norton & Company. ISBN 0-393-97767-6.
^ Stress Management for Health Course. "The Fight Flight Response". Retrieved 19 April 2013.
^ Olpin, Michael. "The Science of Stress". Weber State University.
^ Grohol, John. "What's the purpose of the fight or flight response?". Retrieved 18 April 2013.
^ Goldstein, David (2007). "Evolution of concepts of stress". Stress. 10 (2): 109–20. doi:10.1080/10253890701288935. PMID 17514579. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Gill, A.C. (2004). Revision of the Indo-Pacific dottyback fish subfamily Pseudochrominae (Perciformes: Pseudochromidae). Smithiana Monographs. pp. 1–123.
^ Shelley Elizabeth Taylor, LC Klein, BP Lewis. "Biobehavioral responses to stress in females: Tend-and-befriend, not fight-or-flight" (PDF). Psychological Review. Retrieved 2010-10-04. First described by Walter Cannon in 1932, the fight-or-flight response is characterized physiologically by sympathetic nervous system activation that innervates the adrenal medulla, producing a hormonal cascade that results in the secretion of catecholamines, especially ...{{cite journal}}: CS1 maint: multiple names: authors list (link)
^ Friedman, H. S., & Silver, R. C. (Eds.) (2007). Foundations of Health Psychology. New York: Oxford University Press.
^ Cistler, Josh (2010). "Emotion Regulation and the Anxiety Disorders: An Integrative Review". Journal of Psychopathology and Behavioral Assessment. 32 (1): 68–82. doi:10.1007/s10862-009-9161-1. PMC 2901125. PMID 20622981. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Gross, James (1998). "Sharpening the Focus: Emotion Regulation, Arousal, and Social Competence". Psychological Inquiry. 9 (4): 287–290. doi:10.1207/s15327965pli0904_8.
^ Avero, Pedro (1). "Emotional reactivity to social-evaluative stress: genderdifferences in response systems concordance". Personality and Individual Differences. 27 (1): 155–170. doi:10.1016/S0191-8869(98)00229-3. {{cite journal}}: Check date values in: |date= and |year= / |date= mismatch (help); Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
^ Carthy, T (2010). "Emotional reactivity and cognitive regulation in anxious children". Behavior Research and Therapy. 48 (5): 384–393. doi:10.1016/j.brat.2009.12.013. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
^ Valiente, C (2003). "The relations of effortful control and reactive control to children's externalizing problems: A longitudinal assessment". Personality. 71 (6): 1171–1196. doi:10.1111/1467-6494.7106011. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
^ Reid, Sophie C. (2006). "Cognitive Biases in Childhood Anxiety, Depression, and Aggression: Are They Pervasive or Specific?". Cognitive Therapy and Research. 30 (5): 531–549. doi:10.1007/s10608-006-9077-y. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
^ Beck, Aaron (1979). Cognitive Therapy and the Emotional Disorders. United States: Penguin Books.
^ Weems, CF (2006). "An integrative model of control: implications for understanding emotion regulation and dysregulation in childhood anxiety". Journal of Affective disorders. 91 (2): 113–124. doi:10.1016/j.jad.2006.01.009. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
^ Brendgen, M (2004). "Is there a dark side of positive illusions? Overestimation of social competence and subsequent adjustment in aggressive and nonaggressive children". Journal of Abnormal Child Psychology. 32 (3): 305–320. doi:10.1023/B:JACP.0000026144.08470.cd. PMID 15228179. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
^ Crick, Nicki (1994). "A review and reformulation of social information-processing mechanisms in children's social adjustment". Psychological Bulletin. 115 (1): 74–101. doi:10.1037/0033-2909.115.1.74. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
^ Dodge, Kenneth (1980). "Social cognition and children's aggressive behavior". Journal of Child Development. 51 (1): 162–170. doi:10.2307/1129603. {{cite journal}}: Unknown parameter |month= ignored (help)
^ Mayo Clinic Staff. "Stress symptoms: Effects on your body, feelings and behavior". Mayo Clinic.