Theories of Motivation

General concepts and drive-reduction theory

Physiology has long debated what exactly triggers behavioral reactions. Some researchers believed that specific behavior is activated exclusively by internal programs without the participation of external triggers. Others insisted on the obligatory role of environmental factors as the main guiding elements. Today, science accepts a compromise view: any motivation always includes energetic (motivating) and directing (goal-orienting) components.

One of the basic concepts is the drive-reduction theory. Its main idea is that at a reflex level, the organism strives to eliminate uncomfortable and unpleasant emotional sensations caused by an acute metabolic need. Within this theory, the following mechanisms are distinguished:

• Hunger is interpreted as the physiological desire to eliminate specific pains in the epigastric region arising from rhythmic contractions of the empty stomach walls.
• Thirst is viewed as the urge to remove dryness and unpleasant sensations localized in the oral cavity and pharynx.

The neurophysiological basis of such reactions is considered to be the activity of two reciprocal (mutually exclusive) brain structures: the punishment system and the reward system. At the same time, the leading role in generating emotions is assigned to the stream of nerve impulses coming from peripheral organs.

Physiological theories: from periphery to humoral factors

The study of motivations has gradually evolved from analyzing purely external behavioral acts to searching for subtle internal mechanisms. Several key stages can be identified in this process.

W. Cannon's peripheral theory The American physiologist was the first to focus on local peripheral stimuli. He postulated that signals from various parts of the gastrointestinal tract are the primary initiators of hunger and thirst.

I.P. Pavlov's humoral concept The outstanding physiologist drew attention to the humoral factor, introducing the concept of "hungry blood" into scientific use. According to this idea, the altered chemical composition of the blood directly stimulates the corresponding centers, causing motivational excitation.

The problem with the humoral theory and modern synthesis In its pure form, the humoral concept soon encountered insurmountable contradictions. Observations of conjoined twins, who shared a common circulatory system while maintaining separate neural innervation, clearly demonstrated that their needs and desires could differ completely. This proved that biochemical changes in the blood alone are not enough to form a full-fledged motivation. Today, the concept of multiple factors is recognized—the necessity of uniting regulatory pathways into a single neurohumoral mechanism.

Role of the CNS and hypothalamic theory

In the mid-20th century, the focus of research naturally shifted to the central nervous system. French scientist P. Dell put forward the concept of central motivational state (formulated by analogy with the works of C. Sherrington). According to it, motivation is determined by powerful nonspecific ascending signals coming from the reticular formation structures to the cerebral cortex.

A special place in physiology is occupied by the hypothalamic theory of the American researcher E. Stellar. It states that motivations are formed through the activity of specialized centers in the hypothalamus. These centers are directly influenced by four groups of factors:

1. Cerebral cortex.
2. Inhibitory hypothalamic centers.
3. Sensory stimuli.
4. Humoral substances of the circulating blood.

Experimental evidence The presence of motivogenic centers was convincingly confirmed by experiments involving electrical and chemical stimulation of brain structures:

• Stimulation of the posterolateral region (in the area of the fornix) induces an acute and uncontrollable drinking response in goats.
• Irritation of the lateral hypothalamus forces even completely satiated animals to actively seek out and consume food.

As a result, modern science views motivation as a highly complex structure. In its implementation, the hypothalamus does not work in isolation, but in close conjunction with the limbic system, reticular formation, and various areas of the cerebral cortex.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Mechanisms of functional interaction between the hypothalamus and the cerebral cortex
• Physiology of the reward system and punishment system in the brain
• Influence of the reticular formation on the formation of the central motivational state
• Role of limbic structures in ensuring complex behavioral reactions

Other topics in the "Motivations" section

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