General Characteristics of the Theory
According to P.K. Anokhin's theory, any behavioral act has a complex, stage-by-stage composition that unfolds within the structures of the central nervous system. The most important property of this system is the principle of isomorphism. This means that the central architectonics is completely universal (isomorphic) for any behavioral reactions. It applies equally to the simplest adaptive responses and to the most complex higher mental activity in humans.
The entire process is built exclusively on the activity of the brain, driven by complex, rapidly changing dynamic relationships between the cortex and subcortical structures. Under natural conditions, the brain completes a full cycle from stimulus to response with incredible speed—the formation of the act's structure takes only a few milliseconds.
Stage 1: Afferent Synthesis
The first and primary initiating stage of a behavioral act is afferent synthesis. At this stage, the brain gathers and analyzes all available information to build a foundation for future action.
Afferent synthesis comprises four mandatory components:
- Dominant motivation — the leading element of the entire stage, built on the basis of various current metabolic needs of the organism. Its physiological mechanism relies on continuous neuro-humoral signaling.
- Memory — utilization of past experience to solve the current task.
- Situational afferentation — the aggregate of all input signals concerning current environmental conditions.
- Triggering afferentation — the immediate stimulus that initiates the entire behavioral act.
Stages of Goal and Program Formation
The integration of all components of afferent synthesis triggers the sequential dynamics of systemic organization. This process can be divided into several key steps:
- Decision-making. Once afferent synthesis is complete, the brain must make a choice. Out of a multitude of possible reaction options, only one—the most adequate action—is selected.
- Goal formation. At this stage, the apparatus for predicting the required (desired) result operates.
- Creation of the Action Acceptor (Action Acceptor of Results). A neuronal model of the anticipated result is formed. In the future, the brain will compare the actual outcome against this ideal model.
Execution, Comparison, and Correction
Once the plan is ready, the behavioral act moves to the execution stage. The efferent synthesis is completed, followed by the action itself. The action inevitably leads to a certain result.
Next comes a crucial moment: the comparison stage. The parameters of the actually obtained result are compared with the parameters pre-encoded in the Action Acceptor.
Two outcomes are possible:
- Successful action. If the parameters of the real result fully match the neuronal model in the Action Acceptor, the behavioral act is considered successfully completed.
- Mismatch (error). If the parameters of the achieved result do not match the Action Acceptor, an orienting-investigatory response (OIR) occurs.
In case of an error, the system does not stop. A correction mechanism is triggered: the brain restructures afferent synthesis (taking into account the unsuccessful experience), makes a completely new decision, refines the Action Acceptor parameters, and performs a new action. This cyclic process repeats until the real result matches the ideal encoded in the Action Acceptor.