The perceptual chain is a six-link model to better understand the perceptual process. Its six links influence each other and reconnect in a permanent cycle. A dysfunctional perceptual chain is associated with phenomena such as hallucination.
What is the perceptual chain?
The perceptual chain is a six-member model for better understanding the perceptual process. Sensory chain deals with human sensory perceptions. The human organism is equipped with various sensory structures for processing information and obtaining information from the environment. All sensory structures make use of environmental stimuli, which are received by the organism in the form of bioelectrical excitation. In the body, the partial information from the individual sensory structures is filtered and combined into meaningful overall information. Together, the partial information forms perception. The chain of perception is the basic model of the concept of perception. It has six different links, which are in mutual influence. In this model, the perceptual apparatus faces the external world. The chain of perception is self-contained and can be described as a cycle. In each type of perception, this circuit is involved in the same order. The six links of the chain are stimulus, transduction, processing, perception, recognition, and action.
Function and task
Life is perceiving. This means that perceptions are vital to every organism. Every action is a reaction to sensory information. Perceptions thus help humans orient themselves and assess their environment. Thanks to the perceptual apparatus, humans can thus adjust their actions to the environment. Without the perceptual apparatus, humans would be disconnected from the outside world and would not be able to act in a meaningful way. At the beginning of the perceptual chain is the stimulus. Objects in the environment produce signals that correspond to physically measurable quantities. These signals give the person a picture of his environment and let him assess his relationship to the out-of-body. For this purpose, the stimuli hit the sensory cells of the respective sensory system. The sensory cells are excited by the stimuli from outside and convert various forms of energy in a transduction process into bioelectric or biochemical voltage changes. This is how action potentials are generated. Preprocessing of the received signals usually takes place in the receptors themselves. The actual processing of the information, however, takes place in the brain. Processes of filtering, inhibition, convergence and divergence as well as integration and summation serve in the individual brain regions to obtain overall information. This total information passes through cognition into the consciousness of the human being. Sound becomes tone here. Electromagnetic waves become light. Only the conscious total information leads to an understanding or allocation of the information. Through processes such as remembering, combining, recognizing, associating or judging, the human brain estimates the meaning of a conscious perception. The final result of a perception is the reaction. This reaction usually corresponds to an adapted action. Often, it is the action that makes additional perceptual information available to the person. For example, if a link in the perceptual chain is disturbed, then the reaction to this disturbed perception may correspond to a removal of the disturbance. Man is aware of the connection between individual stimuli and their representation in the central nervous system thanks to cognition. For this reason he recognizes when he is missing a link to the correct course of the perception chain. He can recognize, identify and consciously eliminate disturbances for this reason. In order to gather additional information about a situation, the reaction can be, for example, a palpation or a movement of the eyeball. The perceptual chain permanently connects to itself. The immediacy and speed of each step takes only a fraction of a second.
Diseases and complaints
The perceptual chain plays a role in both general medicine and psychology. Receptor defects in sensory structures, for example, can disrupt the perceptual chain and deprive the individual of adapted responsiveness.The same applies to brain lesions in the areas responsible for processing and classifying perception. Both receptor defects and brain lesions are physiological causes of perceptual illusions or other disturbances in the perceptual chain. On the other hand, mental illnesses without physical causes can also cause perceptual illusions, illusions or hallucinations. In illusions, real facts are perceived in an altered way. This phenomenon characterizes many clinical pictures from the field of psychology and is known, for example, from phenomena such as the spotlight effect. Those affected believe that they are permanently observed and judged by their environment. People with social phobia particularly often suffer from this illusion. In hallucinations, patients perceive things that are not actually there. Without the appropriate environmental stimuli, perceptions of one or all sensory areas may be present. The cause may be psychosis or sleep deprivation. Physiological changes in the brain also sometimes trigger hallucinations. Hallucinations have been observed particularly frequently as a result of brain changes in the context of epilepsy. Perceptual illusions do not necessarily have to be a pathological phenomenon. Especially optical illusions can be achieved by certain color combinations without an actual change or disturbance in the chain of perception. The border between illusion and reality is especially difficult to recognize for the eyes. They work with two-dimensional images and yet give people the feeling of perceiving the environment in three dimensions.
