Motivations

in biology, active states of brain structures, or systemically organized stimuli of the central nervous system that prompt higher animals and man to perform actions (behavioral acts) directed toward satisfying their needs. These acts are either hereditary (instincts) or are reinforced by experience (conditioned reflexes).

Motivations are not confined to the drive for individual or species self-preservation, which represents a necessary condition for the existence of living organisms but is by no means the principal tendency of their goal-directed behavior. Within certain limits, living organisms will actively disrupt their attained equilibrium with their environment; examples of this include the restructuring of relations within a pack or herd and exploratory behavior in animals—not motivated by food shortage or the need for resettlement—when they enter unfamiliar territory. The nervous apparatus of emotions plays an important role in motivations of a similar type.

A distinction is made between individual motivations, which are directed toward the maintenance of homeostasis (hunger, thirst, avoidance of pain, striving toward optimal temperatures); group motivations (care of the young, quest for a place in the group hierarchy, maintenance of the community structure typical for a given species); and cognitive motivations (exploratory behavior, play). Classification of the different kinds of motivation is made according to the feedback mechanism that regulates a given motivation: within the individual, in the case of the satisfaction of hunger or thirst; through interaction with other individuals, including offspring; or through a process of development that reinforces, modifies, or rejects a given motive. Many motivations contain elements of different groups. For example, sexual motivation, which is associated with hormonal restructurings within the organism, can be realized only by interaction with other individuals and is essentially dependent on their behavior.

Information about the brain substratum that activates a given motivation is still incomplete. The neurophysiology of the most elementary motivations—hunger, thirst, avoidance of pain, and sexual attraction—has been studied in detail. Broad ramified systems whose elements are localized in many areas of the brain serve as the neural substratum for these motivations. Biochemical changes within the organism, as well as the action of external stimuli, are transformed during the process of excitation, which activates certain structures of the hypothalamus. From there the motivational excitation spreads to the limbic system and the cerebral cortex, where the program of behavior that is capable of leading to satisfaction of the corresponding need is formed. The discovery by J. Olds and P. Milner (Canada) of brain structures that a test animal stimulates repeatedly with an electrical current (reinforcing systems of the brain, or “pleasure centers”) was significant for the neurophysiological theory of motivation. These experiments in self-stimulation showed that motivations and emotions, interacting with one another, are limited to various brain formations and play an independent role in the organization of behavior. In contrast to experiments in which the brain is stimulated artificially, motivational excitation (the presence of need) is a prerequisite for the activation of the nervous apparatus of the emotions in higher animals and man under natural conditions of existence.

Figure 1. Diagram showing the place of motivation in the structure of the integral behavioral act. Solid arrows indicate activating influences; the broken arrow indicates an inhibiting influence.

The needs of a species, group, or community that are fundamentally not deducible from the needs of the individual are represented in the brains of living beings in the form of motivations of individual behavior, such as the parental instinct, exploratory activity, and reaction to signals from other individuals. To the neural substratum for motivations of this type belong, besides the hypothalamus, certain nuclei of the amygdaloid complex, and the frontal and, partially, the temporal lobes of the cortex. Injury to the frontal areas of the large hemispheres of the brain in man leads to the disturbance of the higher types of motivation that initiate work activity, social contacts, and creativity. At the same time, there is a relaxation of the inhibitions that control elementary motivations.