Yerkes-Dodson law
The Yerkes-Dodson law is a psychological principle that describes the relationship between stress levels and performance efficiency. According to the law, individuals tend to perform better when experiencing moderate stress, while both excessive stress and low stress can hinder performance. The concept originated from experiments conducted in 1908 by psychologists Robert M. Yerkes and John D. Dodson, who observed that rats learned more effectively with a moderate level of electric shock than with either too little or too much shock. This relationship is often represented by an inverted U-shaped curve.
In practical terms, the Yerkes-Dodson law suggests that a certain level of stress—such as deadlines or performance pressure—can enhance focus and physical abilities, facilitating better outcomes in various tasks. However, if stress becomes overwhelming, it can lead to a state known as "frazzle," which negatively impacts clear thinking and performance. Conversely, low stress can lead to disengagement and boredom, resulting in subpar performance. The application of this law has been used in workplace management strategies, though its effectiveness can vary among individuals, as some thrive under high stress while others do not. While the law remains a significant concept in psychology, ongoing debates exist regarding its applicability to human behavior compared to its origins in animal studies.
On this Page
Subject Terms
Yerkes-Dodson law
The Yerkes-Dodson law is a behavioral psychology concept related to the relationship between a person's level of stress and the ability to perform a skill or task. The law proposes that people function better when under a moderate amount of stress. Conversely, performance drops when people are either too stressed or not stressed enough. The law has been known and cited for more than a century. However, some experts state that the law, which is based on animal studies, does not transfer as well to actual human behavior as many have thought.
Background
The Yerkes-Dodson law originated in 1908 after American psychologists Robert M. Yerkes and John Dillingham Dodson conducted an experiment with rats. They trained the animals to choose either a black door or a white door under different lighting conditions by using electrical shocks as a deterrent for incorrect choices. While conducting the experiment, the researchers noted that while mild shocks produced learning, slightly more intense shocks produced better results. However, Yerkes and Dodson discovered that if they increased the shocks too much, the animals appeared to become too stressed to learn. Learning or habit forming occurred most readily with a moderate amount of stress present in the form of the electric shock.
The psychologists charted their findings as an inverted U shape, with one leg of the upside-down U representing the lowest shock level, the other representing the highest shock, and the curve between them reflecting how learning increased, peaked, and then decreased. This became known as the Yerkes-Dodson law. The law was included in many psychology textbooks, and the results were extended to other animals and humans.
In humans, this meant that a certain amount of stress—in the form of anxiety, pressure to perform, risk, or some other emotional strain, not electric shocks—could improve a person's performance at a task. For example, a writer trying to meet a deadline, a goalie facing a shot in sudden death overtime, and a pilot engaged in combat are all in situations in which their ability to perform is crucial to various degrees. Depending on how the individual perceives this stress and how high the level of stress climbs, some may have good results and others may fail under the pressure.
Later research uncovered the science of why this occurs. Emotional stress generates physical effects on the human body. Stress hormones, including epinephrine and cortisol, are released by the endocrine system. The circulatory, respiratory, digestive, nervous, reproductive, and musculoskeletal systems are affected by these hormones and the changes they stimulate in each.
This results in what is often known as the fight or flight response; the body is reacting to the stress as ancient humans would have: by preparing for fighting or fleeing from a danger. Heart rate, blood pressure, and breathing are increased to provide more oxygen and energy, glucose stores are released to help fuel the response, muscles tense, and the nervous system is on full alert. These same responses can help a person attain higher levels of focus and optimize physical abilities, facilitating a better performance. However, too much of these stress hormones can also hamper thinking and physical performance.
Overview
The inverted U used by Yerkes and Dodson equated to three states of arousal, or response to the stress. Some psychologists came to refer to these states as disenchantment, flow, and frazzle. All three affect performance, but only those in flow are able to truly perform at a consistently high level.
The term flow comes from the work of Croatian-born Hungarian psychologist Mihaly Csikszentmihalyi. Csikszentmihalvi used the term to describe the state a person is in when so completely engaged in a task that the rest of the world seems to have disappeared. The task, whether it is work in an office, a challenging physical task, participation in a sport, or some other endeavor, requires enough physical and/or mental energy that the person gives it full attention. There is sufficient motivation in the form of an interest to successfully complete the task to allow the person to reach a higher level of achievement.
Too much stress, however, results in the release of an abundance of stress hormones. This state of frazzle can affect the ability to listen and think clearly. The faster breathing and heart rate that results from the hormone will cause tiredness, as will muscles that are clenched tight for too long. In the short term, these will cause fatigue that will limit the person's effectiveness at the task at hand. In the long run, excessive levels of stress can cause other problems that can further reduce performance. Sleep and digestive problems can result, as can problems with the reproductive system. Chronic illnesses such as high blood pressure and diabetes are also possible.
Disengagement, on the contrary, means the person is bored, disinterested, and unmotivated. This may be because the task has become too routine or is too well known to the person, or because the task is seen as lacking in any significance. Stress level is low, but so is motivation and performance.
Over time, many employers began using the Yerkes-Dodson law as part of their management strategy. They gave employees slightly harder tasks or more work to keep stress levels in the optimal levels for performance. Some also tried to manage high stress levels so that employees were not too stressed to complete their jobs.
Some experts question the validity of the law. Efforts to repeat the experiments have been mixed. In some cases, the test animals adapted to the shocks and stopped responding. In others, they performed much like the rats from the original experiment. Employers using the law in their companies have also found it more difficult to apply to people than to animals. Some people easily handle high levels of pressure and thrive in circumstances in which others would reach a frazzle stage. Others are content with low levels of motivation and perform consistently in situations in which others would become disengaged. Psychologists do state that people can learn to be more motivated doing low-engagement tasks. People can also increase their levels of concentration to be able to reach flow more easily, and learn stress-management techniques to help in times of high stress.
Bibliography
Gino, Francesca. "Are You Too Stressed to Be Productive? Or Not Stressed Enough?" Harvard Business Review,14 Apr. 2016, hbr.org/2016/04/are-you-too-stressed-to-be-productive-or-not-stressed-enough. Accessed 2 Feb. 2018.
Goleman, Dan. "The Sweet Spot for Achievement." Psychology Today, 29 Mar. 2012, www.psychologytoday.com/blog/the-brain-and-emotional-intelligence/201203/the-sweet-spot-achievement. Accessed 2 Feb. 2018.
Hancock, Peter, and H.C. Neil Ganey. "From the Inverted U to the Extended U: Evolution of a Law of Psychology." University of Central Florida, peterhancock.ucf.edu/wp-content/uploads/sites/175/2012/03/Hancock‗Ganey‗From-the-inverted-U-to-the-extended-U-The-evolution-of-a-law-of-psychology‗2003.pdf. Accessed 2 Feb. 2018.
Inglis-Arkell, Esther. "The Flawed Experiment That 'Proved' Stress Is Good for You." Gizmodo, 25 June 2014, io9.gizmodo.com/the-flawed-experiment-that-proved-stress-is-good-for-1595732526. Accessed 2 Feb. 2018.
"Mihaly Csikszentmihalyi." Pursuit of Happiness, www.pursuit-of-happiness.org/history-of-happiness/mihaly-csikszentmihalyi/. Accessed 2 Feb. 2018.
Schlanger, Danielle. "The Optimal Level of Anxiety You Need to Perform Well." Business Insider,19 June 2012, www.businessinsider.com/a-little-anxiety-will-help-you-perform-optimally-but-too-much-is-debilitating-2012-6. Accessed 2 Feb. 2018.
"Stress Effects on the Body." American Psychological Association, www.apa.org/helpcenter/stress-body.aspx. Accessed 2 Feb. 2018.
Yerkes, Robert M., and John D. Dodson. "The Relation of Strength of Stimulus to Rapidity of Habit-Formation (1908)." York University, psychclassics.yorku.ca/Yerkes/Law/. Accessed 2 Feb. 2018.