The drive that produces goal-directed behavior.
The study of motivation is concerned with the influences that govern the initiation, direction, intensity, and persistence of behavior. Three categories of motives have been recognized by many researchers: primary or biological (hunger and the regulation of food intake); stimulus-seeking (internal needs for cognitive, physical, and emotional stimulation, or intrinsic and extrinsic rewards); and learned (motives acquired through reward and punishment, or by observation of others).
Instinct theories, which were popular early in the twentieth century, take a biological approach to motivation. Ethologists study instinctual animal behavior to find patterns that are unlearned, uniform in expression, and universal in a species. Similarly, instinct theory in humans emphasizes the inborn, automatic, involuntary, and unlearned processes which control and direct human behavior. Scientific development of the instinct theory consisted largely of drawing up lists of instincts. In 1908, William McDougall (1871-1938) postulated 18 human instincts; within 20 years, the list of instincts had grown to 10,000. Although instinct theory has since been abandoned, its evolutionary perspective has been adopted by sociobiologists considering a wide range of human behavior, from aggression to interpersonal attraction, from the standpoint of natural selection and the survival of humans as a species.
Drive-reduction theory, which is biologically-oriented but also encompasses learning, centers on the concept of homeostasis, or equilibrium. According to this theory, humans are constantly striving to maintain homeostasis by adjusting themselves to change. Any imbalance creates a need and a resulting drive—a state of arousal that prompts action to restore the sense of balance and thereby reduce the drive. The drive called thirst, for example, prompts us to drink, after which the thirst is reduced. In drive-reduction theory, motivation is seen not just as a result of biological instincts, but rather as a combination of learning and biology. The primary drives, such as hunger and thirst, are basic physiological needs that are unlearned. However, there is also a system of learned drives known as secondary-drives that are not biological (such as the desire for money) but that prompt action in much the same way as the primary drives.
Another biologically-oriented theory of motivation is arousal theory, which posits that each person is driven to achieve his or her optimum level of arousal, acting in ways that will increase this level when it is too low and decrease it when it is too high. Peak performance of tasks is usually associated with moderate levels of arousal. Researchers have found that difficult tasks (at which people might "freeze" from nervousness) are best accomplished at moderate arousal levels, while easier ones can be successfully completed at higher levels.
Psychologically-oriented theories of motivation emphasize external environmental factors and the role of thoughts and expectations in motivation. Incentive theory argues that motivation results from environmental stimuli in the form of positive and negative incentives, and the value these incentives hold at a given time. Food, for example, would be a stronger incentive when a person is hungry. Cognitive theories emphasize the importance of mental processes in goal-directed behavior. Many theorists have agreed, for example, that people are more strongly motivated when they project a positive outcome to their actions. Achievement-oriented individuals learn at an early age to strive for excellence, maintain optimistic expectations, and to not be readily discouraged by failure. Conversely, individuals who consistently fear failure have been found to set goals that are too high or too low and become easily discouraged by obstacles. The concept of learned helplessness centers on how behavior is affected by the degree of control that is possible in a given situation.
American psychologist Abraham Maslow developed a five-level hierarchy of needs, or motives, that influence human behavior. The "lower" physiological and biological urges at the bottom of the hierarchy must be at least partially satisfied before people will be motivated by those urges closer to the top. The levels in Maslow's system are as follows: 1) biological (food, water, oxygen, sleep); 2) safety ; 3) belongingness and love (participating in affectionate sexual and non-sexual relationships, belonging to social groups); 4) esteem (being respected as an individual); and 5) self-actualization (becoming all that one is capable of being).
In addition to individual motivations themselves, conflicts between different motivations exert a strong influence on human behavior. Four basic types of conflict have been identified: 1) approach-approach conflicts, in which a person must choose between two desirable activities that cannot both be pursued; 2) avoidance-avoidance conflicts, in which neither choice in a situation is considered acceptable and one must choose the lesser of two evils; 3) approach-avoidance conflicts, where one event or activity has both positive and negative features; and 4) multiple approach-avoidance conflicts involving two or more alternatives, all of which have both positive and negative features.
Hoffman, Edward. The Right to be Human: A Biography of Abraham Maslow. Los Angeles: Tarcher, 1988.