It is difficult to represent, and this is also evident based on the example of instincts that can exist (and be formed on the basis only of genetic mechanisms) the certain rigidly programmed purpose, motive, in accordance with which is formed the specific model of behavior. The same hunger - these are not only tendency toward the food, but also the avoidance of unpleasant internal sensation. In other words, avoidance (state of discomfort) - is primary, and the motivation of the search for food - is second. Instinct is characterized by the fact that the "situation of avoidance" is created by the internal physiological processes, which are started by internal or external signals.
Approximate diagram of the instinct:
With the start of genetic program (innate reactions) or with the disturbance of homeostasis in the organism appear the physiological changes, which cause the sensation of discomfort (external or internal irritation), that by analogy with the painful reaction it is possible to treat as unconditional reaction (reflex). more complex unconditional reaction becomes not only composing the chains of unconditional reactions, but also being complicated with the advance upward on the pyramid- diagram (outgrowing by emotions and motives).
Search activity in other one or manner or another weakens this stress, for example, by partial or complete satisfaction of need. However, concept "satisfaction of the need" for the psychological sense does not synchronize with the real satisfaction. Satisfaction in the first sense, as a rule, anticipates satisfaction in the second sense. For example, the greatest pleasure of men is experienced having only approached the food, but not after dinner, in saturation state. Psychological satisfaction (positive emotion in the justified state), in the essence, has phantom nature. But precisely this mechanism directs behavior in the situation of avoidance to the side of weakening internal stress, ensuring the complex forms of behavior. For example, the instinct of building nest, parental, care, etc. (See: Sexual inclination. Psychology, physiology. )
The sidelights to the text and the diagram - in the article: Reflexes, emotions, motives.Based on materials of Vladimir Ivanov's article