2.1. The concept of instinct. Modern ideas about instinct

The history of the study of instinctive behavior goes back several centuries; however, a clear, unambiguous and accepted definition of instinct has not yet been worked out.

Ever since the work of Charles Darwin, by instinctive behavior they understand that part of the behavior of animals that is species-typical and hereditarily fixed. One of the first attempts to give an accurate interpretation of the concept of "instinct" was the definition of the German zoologist G.E. Ziegler (Instinct, 1914). He singled out five points for which “instinctive” behavior differs from “rational”.

Instinctive behavior:

• hereditarily fixed;

• for its development does not require additional training;

• the same for all individuals of this species, i.e., species-specific;

• optimally corresponds to the organization of the animal, its physiology;

• is optimally adapted to the natural living conditions of animals of a given species, often associated even with cyclical changes in the conditions of existence.

This definition of instinct has its drawbacks, for example, it does not take into account the possible variability of instinctive behavior.

The famous Russian physiologist I.P. Pavlov (1849–1936, “Conditional reflexes: a study of the physiological activity of the cerebral cortex”, 1925), one of the creators of the reflex theory, suggested that the concepts of reflex and instinct are identical. In this case, an unconditioned reflex corresponds to instinctive behavior. This view significantly narrowed the concept of instinct, however, it was very convenient to study the acquired components of behavior, higher nervous activity.

The Dutch scientist N. Tinbergen (1907–1988) defined instinct as “a hierarchically organized nervous mechanism that responds to certain proposed and resolving impulses (external and internal) with fully coordinated, vital and intrinsic movements.” ^[6]

Tinbergen created a hierarchical theory of instinct, which we will explore later.

Soviet physiologist A.D. Cloning gives the following definition: “Instinct is a set of motor acts and complex behaviors characteristic of an animal of a given species arising from stimuli from the external and internal environment of the body and occurring against the background of high excitability of the nerve centers associated with the implementation of these acts. This high excitability is the result of certain changes in the nervous and hormonal systems of the body, the result of changes in metabolism. " ^[7]

Slonim drew attention to the fact that in the process of the vital activity of the organism, instincts can appear and disappear. For example, the instinctive behavior associated with the sucking reflex in young mammals disappears over time, but instincts appear regarding reproduction and nest building activity. HELL. Slonim indicates constancy as the main property of instinctive behavior. In his opinion, minor individual differences cannot disprove this property, but are only fluctuations in its manifestation.

Plasticity instinctive behavior. This question is one of the key issues in zoopsychology. In order to understand the behavioral reactions of an animal, it is important to find out whether the innate behavior is permanent or it can be subject to modifications. Currently, scientists have concluded that individual instinctive actions are not inherited, only the framework within which the development of instinctive reactions occurs is genetically fixed.

An invaluable contribution to the development of this problem was made by the Russian biologist and psychologist V.A. Wagner (1849–1934). In the book “The Biological Foundations of Comparative Psychology” (1913–1919), he came to the conclusion that instinctive behavior develops under the influence of external environmental influences; therefore, it can never be invariable. It is a plastic and labile system that develops under the influence of natural selection. Stable, however, are only species-typical frames that determine the amplitude of instinct variability.

Subsequently, other scientists continued to develop questions of the variability of instinctive behavior. So, L.A. Orbeli revealed the dependence of the degree of plasticity of animal behavior on maturity.

A.N. Prompt pointed out that plastic instinctive behavior is made by individual conditioned reflex components acquired during life. As mentioned above, Promptov introduced the concept of "species behavior stereotype", i.e., behavioral features typical of this species. They are formed by a combination of innate, type-specific instinctive reactions and conditioned reflexes acquired on the basis of them during ontogenesis. These representations A.N. Promptov were illustrated by the observations of E.V. Lukina for nesting activity (see topic 1.1, p. 16).

Promptov's ideas about the connection of innate and acquired components in the behavior of animals are very important for a correct understanding of the problem of instinctive behavior. However, according to these ideas, the instinctive actions themselves are not subjected to variations, their variability is provided only by acquired components.

At present, it is believed that instinctive behavior is subject to changes within the limits of the hereditarily fixed norm of response. These frames are type-specific; beyond their limits, instinctive behavior cannot change under normal conditions. At the same time, in extreme conditions beyond the response norm, the individual experience of the animal plays a large role. It allows instinctive behavior to change quite strongly. In addition, in addition to highly conservative innate mechanisms, there is a variable component of behavior.

A.N. Severtsov in his writings gave an analysis of the variability of the instinctive and acquired component of behavior. Severtsov showed that in mammals adaptation to changes in the environment is carried out in two ways: through a change in organization, that is, the structure and functions of the body, and through a change in behavior. Changes in the organization allow you to adapt only to slow changes in the environment, because they require a long period of time. Changes in behavior do not require a restructuring of the structure and functioning of the animal's body, therefore, they are performed at a sufficiently high speed. Such changes arise due to acquired, individual forms of behavior and allow the animal to adapt to sudden changes in the environment. In this case, the greatest success is achieved by animals that can quickly develop plastic skills, whose behavior is flexible, and their psychic abilities are quite high. With this Severtsov connects the progressive development of the vertebrate brain in evolution.

According to Severtsov, instinctive behavior is not changeable enough; therefore, its significance in evolution is approximately comparable to changes in the structure of the animal's body. Changes in innate behavior can also allow an animal to adapt to slow environmental changes. However, the role of such changes should in no case be underestimated.

According to Severtsov, "instincts are the essence of species-specific adaptations, useful for the species as much as these or other morphological signs, and just as constant."

The ability to learn, according to Severtsov, depends on the hereditary height of mental organization. Actions in this case are not instinctively fixed. And in the instinctive behavior hereditarily fixed and action, and the level of mental organization. In other words, instinctive behavior is an innate program of action that is implemented during the accumulation of individual experience.

Thus, the instinctive, innate, behavior of animals is determined by a genetically fixed program of action, which is implemented during the acquisition of individual experience. Instinctive behavior must be fairly consistent and stereotypical, because it relates to vital animal functions. If the instinct depended on the conditions in which the development of each representative of the species occurs, individuals would not be able to use the species experience. The slight plasticity of instinctive behavior is designed only for extreme changes in conditions. The ability to survive in all other changing conditions of existence is provided by acquired components of behavior, learning processes. These processes allow you to adapt a fairly rigidly fixed innate program of behavior to specific environmental conditions. With all these changes, the hereditary program itself must remain unchanged in order to ensure the performance of vital functions.