What is Inhibition?
Inhibition, in psychology, is restraint on an otherwise natural and spontaneous thought or action. In physiological psychology, inhibition is a normal regulatory function of the nervous system. Walking, for example, requires the coordinated inhibitions of certain muscle groups at particular times and in particular sequence. These inhibitions, transmitted from the brain by the spinal cord and peripheral nerves, are involuntary signals stopping or retarding the contractions of the appropriate muscle groups.
The term "inhibition" is more important in personality theory, where it denotes a mental restraint functioning to protect the individual from anxiety. An inhibition may be a conscious reluctance to act in a way that is contrary to one's principles and that would arouse mental conflict; but the term usually denotes an unconscious defense mechanism which in many cases is reflected in the ego by a rationalization or compromise. Any experience or feeling that arouses anxiety in a person and thus threatens his well-being tends to become inhibited.
Inhibition is not always beneficial. Anxiety is a signal of danger, and when it is suppressed by inhibition the result may be an obliviousness to danger and an incapacity to deal with it. Thus an individual may inhibit ideas that are threatening to him even though the resulting unavailability of the ideas prevents him from thinking constructively about his difficulties.
In Inhibitions, Symptoms and Anxiety (1925), Sigmund Freud discussed the anxiety that occurs when so-called "ego-alien" impulses (impulses unacceptable to the individual) threaten to manifest themselves in the individual's thinking or behavior. Such anxiety may give rise to defense mechanisms of several types, of which the most important (the primary defense mechanism) is inhibition. Inhibition includes not only simple denial of the ego-alien impulses but also repression, the forgetting (rejection from consciousness) of unacceptable impulses and experiences. In neobehaviorist psychology, "inhibition" refers to the prevention of an action, "repression" to the prevention of a thought or feeling. Thus a person may be said to take a drug to overcome his inhibitions if the drug frees him to behave in a way he could not ordinarily allow; but if the drug frees him to experience feelings that would normally engender intolerable anxiety, it is overcoming his repressions.
The term "inhibition" also has two important meanings in learning theory. In Pavlovian conditioning, the subject develops an inhibition against any unrewarding response to a simulus. When the distinction between correct and incorrect responses is very subtle, the subject may contract a so-called "experimental neurosis": either an inhibitory reaction, in which the subject fails to respond to the conditioned stimulus, or an excitatory reaction, in which the subject responds to any environmental change, however slight.
Finally, experiments in conventional learning have established that learning may inhibit later learning (proactive inhibition), and that later learning interferes with the retention of earlier learning (retroactive inhibition). In each case the inhibition increases in proportion to the similarity in form and dissimilarity in content of the materials learned.