Stages of action formation and execution

Introduction to behavioral acts

The understanding of how a person plans and carries out any purposeful actions is grounded in the theory of functional systems. This concept explains the mechanisms of higher nervous activity, demonstrating that successful behavior requires complex self-regulation. The key idea is that before performing an actual physical or verbal action, the brain carries out extensive internal mental work aimed at predicting the future outcome. This entire process can be divided into two fundamental stages: the formation of intention and the subsequent evaluation of the result.

Stage A: Formation of intention

The process of forming an intention occurs as internal mental activity long before any visible external action is performed. This preparatory period includes three crucial sequential links:

• Afferent synthesis (AS). At this initial stage, the central nervous system actively processes a massive array of incoming information from the outside. Simultaneously, the body's current motivation is analyzed.
• Decision making (DM). Based on the results of the afferent synthesis, the brain makes a conscious choice of one specific goal from multiple possible options.
• Formation of the acceptor of action results (AAR). This is a unique physiological apparatus of anticipation. It constructs an ideal mental model (or image) of the result that should be obtained in the future.

Example of intention formation: If a person plans to perform a verbal behavioral act, a mental, yet unspoken model of the phrase "Give me a glass" is formed in advance within their AAR.

Stage B: Evaluation of the result

Once the decision has been made and the action is actually executed (for example, the phrase has been spoken aloud), the control stage begins. It is necessary for comparing the actually obtained result with the one that was initially planned.

1. The parameters of the actually achieved result (the already spoken phrase "Give me a glass") are fed back into the central nervous system via special feedback channels.
2. The brain continuously compares the real result with the ideal model that was pre-established in the AAR.
3. In the event of a complete match of parameters, the action is considered successful and is completed. In case of a mismatch (for example, if a person slips up), the process of active activity correction is triggered.

Behavior, mental activity, and interhemispheric asymmetry

The theory of functional systems also explains more complex forms of mental activity. An interesting example is singing, which from the perspective of normal physiology is viewed as a form of cognitive activity, specifically — a form of its verbal quantization.

The process of singing is always built on an emotional basis: learning the melody occurs first, and only then is it filled with specific words. As a result of this synthesis, behavioral systemquants are formed — individual bars and verses.

Full-fledged mental activity is impossible without close interaction between the cerebral hemispheres, which operate on the principle of mutual complementarity:

• The right hemisphere (in right-handers) provides the sensory and emotional components of thinking.
• The left hemisphere takes over the functions of language and speech.

Both hemispheres do not compete, but dynamically assist each other to achieve final adaptive results, harmoniously combining the emotional and verbal bases of behavior.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Mechanisms of feedback afferentation in the central nervous system
• Physiological bases of dominant motivation
• The concept of systemquants using other types of activity as an example
• The role of emotions in the formation of a behavioral act according to P.K. Anokhin

Other topics in the section «Systemic Structure of Human Mental Activity»

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