Psychology What is Motivation? & Hunger
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Introduction
A dog’s motivation seems straightforward: offer the dog a treat, and it will perform all sorts of tricks. Human motivations, however, are far more complicated. Food and sex motivate us, just like they do most animals, but we often do amazing, brave, horrifying, or death-defying things because of the importance we ascribe to intangible principles.
Millions of people around the world fast for religious or personal reasons, ignoring hunger. Some people enter eating contests, which challenge them to ignore their full stomachs and eat huge amounts of food. King Edward VIII of England gave up his throne to marry an American divorcée, and Roman Catholic priests give up sex for their calling. Why would people do these things? Food, sex, and achieve-ment are motivations for all of us, but motivation can also be as unique as each individual.
What Is Motivation?
A motive is an impulse that causes a person to act. Motivation is an internal process that makes a person move toward a goal. Motivation, like intelligence, can’t be directly observed. Instead, motivation can only be inferred by noting a person’s behavior.
Researchers have proposed theories that try to explain human motivation. These theories include drive reduction theories and Maslow’s hierarchy of needs theory.
Drive Reduction Theories
Drive reduction theories of motivation suggest that people act in order to reduce needs and maintain a constant physiological state. For example, people eat in order to reduce their need for food. The idea of homeostasis is central to drive reduction theories.Homeostasis is the maintenance of a state of physiological equilibrium.
Drive reduction theories fail to explain several aspects of motivation:
- People sometimes aren’t motivated by internal needs.
Example: Some people fast for long periods for political causes, despite feeling extreme hunger.
- Sometimes, people continue being motivated even when they have satisfied internal needs.
Example: People sometimes eat even when they don’t feel hungry.
- People are often motivated by external incentives as well as internal needs.
Example: If a person is hungry, he or she may choose to eat a salad rather than a cheeseburger because he or she wants to be slimmer.
Intrinsic and Extrinsic Motivation
A motivation may be intrinsic, extrinsic, or both. Intrinsic motivation is the motivation to act for the sake of the activity alone. For example, people have intrinsic motivation to write poetry if they do it simply because they enjoy it.Extrinsic motivation, on the other hand, is the motivation to act for external rewards. For example, people have extrinsic motivation to write if they do so in the hopes of getting published, being famous, or making money.
Incentives
An incentive is an environmental stimulus that pulls people to act in a particular way. Getting an A on an exam may be an incentive that pulls a student toward studying.
Maslow’s Hierarchy of Needs
In the 1970s, the psychologist Abraham Maslow suggested that people are motivated by a hierarchy of needs:
- First, most basic level: physiological needs, such as the need for food, water, safety, and security.
- Second level: needs for social interaction, such as the need to belong.
- Third level: needs for esteem, which include the need for respect from oneself and others.
- Fourth level: needs for self-actualization, or realizing one’s full potential.
Maslow believed people pay attention to higher needs only when lower needs are satisfied.
Hunger
Hunger is a complicated motivation; people don’t eat only because they need food. Many factors, both biological and environmental, influence hunger. These factors interact with one another in many ways.
Biological Factors
Researchers believe certain genetic differences among individuals play a role in hunger. The brain, the digestive system, and hormones are all involved in influencing hunger at the biological level.
Genetic Differences Among Individuals
Researchers theorize that people have a genetically influenced set point for body weight. If a person’s weight rises too far above his set point, his appetite decreases, or he uses up more energy. His weight then returns to its set point. If, on the other hand, his weight falls too far below his set point, his appetite increases, or he uses less energy. Once again, he returns to his set point.
The set point is maintained not only by food intake and energy expenditure but also by the body’s basal metabolic rate, another genetically influenced variable. Basal metabolic rate is the rate at which a person at complete rest uses energy.
Some researchers disagree about set points and believe that people can reset their normal weight if they add or lose pounds slowly. They also point out that people usually gain weight when they have easy access to rich foods.
The Brain
Researchers believe three areas in the hypothalamus play a key role in regulating hunger:
- The lateral hypothalamus is involved in recognizing hunger. In rats, damage to the lateral hypothalamus results in loss of interest in eating.
- The ventromedial nucleus of the hypothalamus is involved in recognizing satiety or fullness. In rats, damage to the ventromedial nucleus results in excessive eating and weight gain.
- The paraventricular nucleus of the hypothalamus is also involved in hunger regulation. When the paraventricular nucleus of a rat is damaged, the rat will eat a very large quantity of food at each meal.
The Digestive System
The digestive system influences hunger in several ways. For instance, after a meal, the stomach and intestines send nerve impulses to the brain to help people recognize that they are full.
The body converts food to glucose, a simple sugar that acts as an energy source for cells. The level of glucose in the blood affects hunger. Low blood glucose increases hunger; high blood glucose decreases hunger.
Hormones
The hormone insulin also plays an important role in regulating hunger. Insulin allows cells to access glucose in the blood. When the pancreas secretes insulin, hunger increases.
Diabetes is a condition caused by a deficiency of insulin. People who have diabetes take injections of insulin. Without these injections, their cells would be unable to use the glucose in their blood.
Another hormone involved in hunger regulation is leptin. Fat cells in the body secrete leptin and release it into the blood. When the leptin level in the blood is high, hunger decreases.
Environmental Factors
Many environmental factors influence hunger, including the availability of rich foods, taste preferences, habits, memory, stress, and cultural attitudes.
