Perception is known as the steps of perception including the content of perception. Perception thus includes unconscious processes such as the filtering and evaluation of stimuli and conscious processes such as the classification and interpretation of perception. Perceptual disorders can have psychological or physical causes.
What is perception?
Perception is known as the steps of perception including the content of perception. Perception thus includes unconscious processes such as the filtering and evaluation of stimuli and conscious processes such as the classification and interpretation of perception. Human perception is characterized by numerous sub-processes. The sensory cells are the first instance of perception. Stimuli from the external world or from our own body reach these receptors, are converted into action potentials and travel via afferent nerve pathways to the central nervous system. Not all stimuli are processed at all. Perception works with filter systems that serve as protection against stimulus overload. Only relevant stimuli can reach the human consciousness at all. In the central nervous system, stimuli are integrated, added up, ordered and, in the final step, interpreted. The process of perception includes all sub-steps of the human perceptual process. In the broader definition, perception also refers to the content of perception, which is always a subjective one due to the evaluation and filtering processes. A percept of a certain situation never corresponds to an objective impression, but only to a subjectivized partial aspect of reality. Perception thereby outlines the individual steps that give rise to this partial aspect of reality in human consciousness.
Function and task
Perceptions consist of unconscious processes of individual perception or information processing. In the consciousness of the individual, these processes give rise to imaginary images of the perceived partial aspects. Perception thus leads to an involuntary and unconscious way of selecting, structuring and classifying perceptions. Thus, perception corresponds to a selective-subjective inventory of situations of the external environment. Together with the subjective content of perception, the term refers to the neurophysiological basis of sensory perception. The mental processing of perception corresponds to an attentional directing, recognizing, judging and subsuming in the sense of cognition. Perception, however, also includes the unconscious and emotional processes during perception processing, which can be summarized under the term sensation. As a term, perception was first applied in the Stoa to denote clear and infallible perception. René Descartes adopted the term as perceptio ab imaginatione et a sensibus, meaning a grasping with the aid of imagination and the senses. The term influenced empiricism and sensualism and corresponded in the broadest sense to sensory perception. George Berkeley coined the notion “to be is to perceive,” thus tying life itself to the concept of perception. Gottfried Wilhelm Leibniz first used the concept of a small percept that occurs below the threshold of consciousness. For Immanuel Kant, perception was a sub-form of the imagination that alters the subjective state of the individual. With Johann Friedrich Herbart, the concept of perception underwent a turn, as he used it to refer to the reception of what is sensually perceived. In today’s understanding, on the one hand, perception includes the perceptual chain and thus consists of an incoming stimulus, transduction, processing, perception, recognition, and an action. On the other hand, today’s term also includes the cognition of what is perceived and thus embraces filter effects, context dependence, and experiential influence. In the biological sense, perception corresponds both to the reception and processing of sensory information and stimuli, and to the processing and interpretation of these stimuli. Sensory stimuli are not percepts until they undergo cognitive subjective processing.
Diseases and complaints
Perception has clinical relevance only when it is pathologically altered. Such an alteration may be due to physiological causes, but it may also be purely psychological. Psychological causes refer to distorted perception.Disease patterns such as paranoia and depression are characterized by such. Since perception is characterized by subjective filters, a psychological cause for pathological perceptions may correspond to a traumatic experience, for example. Stimuli are filtered and interpreted on the basis of previous experiences. A distortion of perception can thus correspond, for example, to an extremely pessimistic view of the world, which allows primarily bad impressions from reality to enter the consciousness of the affected person and thus promotes depression. A distortion of perception is said to occur as soon as the subjective perception of the individual differs extremely from the objective reality. A distortion of perception characterizes, for example, clinical pictures such as anorexia. Physiological causes of disturbed perception, on the other hand, are primarily neurological disorders or diseases. As the first instance of perception, the sensory cells are connected to the central nervous system via afferent nerves. If these afferent nerve pathways are damaged in the course of trauma, tumor disease, inflammation, or degeneration, then insensitivity can occur. On the skin, for example, such a sensation of discomfort may correspond to a disturbed cold-hot sensation or numbness. In addition to lesions of the afferent pathways, lesions in the brain can also interfere with the processing of stimuli. Such lesions can result, for example, from diseases such as multiple sclerosis. Strokes or tumors in the central nervous system can also alter perception or even make it impossible. Physiological perceptual disorders sometimes also present themselves after the use of drugs. For example, some drugs contain substances that can become active as neurotransmitters. Hallucinations of various sensory systems can therefore accompany drug use. Accordingly, the causes of impaired perception can be manifold and always require medical clarification. During this clarification, it is first determined whether the disturbed perception is due to a physical or psychological cause.
