Systemic Organization of Behavior
In response to episodic environmental changes, organisms react reflexively. All reflex responses are divided into innate (simple and complex unconditioned reflexes) and acquired (conditioned reflexes).
However, living organisms do not merely respond passively to stimuli; they construct active behavior to master environmental factors and satisfy their primary needs. The units of such activity are termed behavioral system quanta. Human and animal life consists of a continuous succession of system quanta, each directed toward a specific result.
If a species inhabits a relatively stable ecological niche across generations, its behavior is quantized primarily via the innate type. This is particularly prominent during early ontogenesis in higher animals. In such cases, system quanta unfold autonomously without requiring specialized training.
The Nature of Instincts
Several perspectives exist regarding the nature of instinctive behavior:
- I.P. Pavlov viewed instincts as complex unconditioned reflexes.
- D. Hebb described them as innate forms of the organism's basic drives (hunger, fear, aggression, sex).
- Ethologists (K. Lorenz, N. Tinbergen) defined instincts as genetically determined patterns of behavior.
From the perspective of systems physiology, an instinct represents a genetically rigid program. Absolutely all components of an instinctive system quantum—from initial need and motivation to goal-directed activity and final reinforcement—are encoded in the genome.
An instinct includes an innate apparatus for anticipating and evaluating results. If an animal encounters a novel environment or an obstacle on the path to satisfying metabolic needs, innate mechanisms of orienting-exploratory activity are triggered.
Rigid Programming and the Digger Wasp Example
Any form of instinctive behavior obeys a feed-forward program determined by a final, vital result. All stages are strictly subordinated. To proceed to the next step, the organism must receive full afferent feedback regarding the achievement of the preceding intermediate result.
A classic example of such rigid programming, described by J. Fabre, is the reproductive behavior of the great golden digger wasp (Sphex occidentalis). Its activity is triggered by hormonal changes (internal need) and external factors (temperature, humidity).
Wasp's Algorithm of Action:
- Digs a burrow of a specific shape.
- Hunts a field cricket.
- Paralyses the prey with three stings to the nerve ganglia.
- Transports the cricket and leaves it at the burrow entrance.
- Descends into the empty burrow to inspect it.
- Drags the prey inside and lays an egg.
- Repeats the hunt 1–2 more times.
- Seals the entrance (final result).
If during the burrow-inspection phase (step 5) an experimenter moves the cricket away, the wasp exits, finds it, places it back at the entrance, and invariably descends for another inspection. It cannot drag the prey inside without completing the 'leave at entrance — inspect' cycle. This cycle will repeat indefinitely. However, if the program is fully completed (the entrance is sealed), complete destruction of the nest no longer elicits any reaction from the wasp—the algorithm has run its course.
Conditions for the Formation of Innate Behaviors
For an instinctive program to launch and successfully conclude, two global factors must strictly coincide:
- Presence of an internal need (nutritional, defensive, reproductive).
- Action of 'key' environmental factors.
External stimuli play a releasing (triggering) role, guiding the animal toward the final adaptive result. In some cases, instinctive system quanta may be initiated exclusively by metabolic shifts in the internal environment, whereas external factors merely accelerate or inhibit this endogenous process. However, if specific signaling factors are entirely absent from the environment (e.g., the correct type of soil for nest building), the execution of the genetic program becomes impossible. Even under acute internal need, the animal cannot execute the chain of actions, ultimately leading to local species extinction.