Habituation

Habituation ( from Latin: habituari: have something in itself or habitus: appearance, posture; adjective habitually: become a habit ), also known as habituation, habituation or learned behavior suppression, called a simple ( and humans in general non- conscious ) way of learning. Habituation begins when an individual is repeatedly exposed to a stimulus, which turns out to be insignificant. The response to this stimulus then weakens gradually and finally remains perhaps completely. If you keep following the occurrence of habituation to the stimulus long enough away, the responsiveness of the individual increases again in the rule. This decrease of central nervous reaction must be distinguished from the peripheral reaction caused by decrease adaptation.

The opposite of habituation is sensitization.

Conceptual history

The term habituation ' wrote William Thorpe (1944 ) in a scientific paper in the behavioral terminology and defined it as " an activity of the central nervous system that causes innate responses to weak fault and warning signals decrease as the stimulus for long periods continues, but no unfavorable impact " ( " an activity of the central nervous system whereby innate responses to mild shock and warning stimuli wane as the stimuli continue for a long period without unfavourable results " ).

Habituation effects so that an individual learns not to respond to certain stimuli, so that constantly disappears from existing stimulus patterns of perception and "useless " reactions spared the individual.

Be distinguished from habituation is the decrease in response to a frequently repeated stimulus due to fatigue or due to an adjustment of the sense organs ( adaptation) to the stimulus, as for example in the eye during the transition from darkness to himself - initially dazzling - takes brightness.

Examples of habituation in animals

Habituation, as already described Thorpe, cause learned alarm stimuli from the environment of an animal ultimately lead to no measurable reaction more.

A well-known example of learned alarm stimuli are the commands that are the holder his dog: " Hasso, from " "! Hasso, come on," Frequently, however, to observe that dog owners express these commands though, without this but recognizable to a reaction of the animal performs. The holder can then, in turn, often no immediate consequences for the dog to follow, perhaps he embeds his orders instead in a torrent of verbal abuse a. The dog's behavior can be interpreted to mean that he has become accustomed, that the cries uttered by the holder follow any unfavorable effects, so the dog does not show any response to the commands previously learned.

Habituation but can also lead to lack of innate response reactions. A newly Come into the budget rabbit lying resting in the cage, depends, for example immediately when a short man leans without addressing the animal over the cage and then go away again immediately. This has to be interpreted as a precursor to flight readiness reaction of the animal weakens gradually and finally remains completely out when the movements about the cage have no consequences for the animal.

The beep sounds of a geratenen from the nest young house mouse run regularly to the fact that the mother leaves the nest, approaching the young animal and transfer it back into the nest. This innate, designated as an entry Ever Hold reaction is also executed in the experiment, when the beep sounds of nestlings be played from a tape. The mother then approaches to the speaker that after repeated playing of this approach remains, however.

A dog sleeping at night and getting noticed in the early morning, at the same time the newspaper vendor on the property will ignore this after a certain period of acclimatization and just go back to sleep, unless an immediate consequence fails, the newspaper supplier therefore does not react to the dog and the dog the newspaper carriers also can not come close. If the newspaper supplier, however once sooner or later, the dog is likely to strike because the Habituationsprozess refers to a specific time of day and the arrival of the newspaper vendor to a different time of day not in Habituationsprozess " newspaper supplier comes every morning at a certain time " is included. There is a Dishabituierung because the stimulus undergoes an unexpected change in a factor.

Habituation in humans

An early study for the detection of habituation in humans published in 1925 the Berlin pediatrician Albrecht Peiper, after he found that newborns react even a few minutes after birth to acoustic signals ( tones of a toy trumpet ) with altered body movement. He tested to see if even the unborn are already responding by kicking altered to such sounds. His observations showed that the reactions of the unborn to a car horn failed, the weaker, the more often they had been exposed to the sounds. Later, other researchers have shown that newborns also respond to repeated proffered olfactory and visual stimuli with habituation if they remain without consequences, are thus not amplified.

Another example of habituation in humans is the habit of clothing, as it is every naturists known: Who has borne neither pants nor shirt on vacation for several weeks, in his return to the textile culture by constantly pressing the fabric against skin and body hair initially be considerably irritated, but have become accustomed again to this duration stimulus after a short time. Also, a new pair of glasses may initially cause such irritation to nose and ears, which later go through habituation lost again.

The fact that the phenomenon of habituation to no mere " exhaustion " of the sensory cells involved in the perception of the stimulus is, one can easily understand the following example: The man used to it after a short time, for example, to the night, even sums of vehicles on a remote highway until he no longer perceives this background noise disturbing. But as soon as the sound skips, because you stayed in an absolutely quiet place, you notice that something is " not right ".

Properties of habituation

A major problem in identifying lies in the distinction from fatigue or slackening (English: fatigue ) and sensory adaptation of the organism. Suppose we consider the reaction of a rat on a very bright light. Initially, the rat shows a very strong reaction - it shows a startle response ( short jumps in the air). With repeated stimulus presentation, this reaction takes its strength from successively. If this decrease in reaction now evidence of habituation? You could also be due to fatigue of the rat - they would simply not constitutionally able to constantly perform a strong startle response. Also, the reaction decrease could have been caused by sensory adaptation. Perhaps the rat is after the performance of the light for a while, blinded ', so can not adequately perceive the other presentations of the stimulus.

A number of specific properties that only occur in habituation, help to distinguish them from other processes.

Stimulus specificity

Habituation is lovely specific. This means that the response habituated only to a certain stimulus ( with increasing dissimilarity between two stimuli habituation of the reaction is being waived ). This habituation of fatigue can be distinguished. If the organism is constitutionally paralyzed or tired, then all his reactions should occur in reduced strength. A habituated reaction only occurs to a certain stimulus. If another stimulus is presented, the response to him continues unabated. For example, the rat: In the repeated presentation of a very loud piercing tone, the rat shows a strong startle response ( she jumps briefly in the air), which is becoming weaker with repeated stimulus presentation. Now the rat is exposed to an electric shock. If the rat to electric shock shows an undiminished strong startle response, then this would be a proof that the reaction would have been habituated to the sound. When the rat but also in the shock is a very weak response, it would be an indication of overall fatigue of the animal.

Reaction specificity

Habituation is reactive specifically. If a response to a stimulus was habituated, another reaction must not be habituated to the same stimulus. Thus, habituation of sensory adaptation can delimit. If an organism a certain stimulus can not perceive adequate ( is blinded by bright light, for example ), then all reactions should be reduced to this stimulus appear strong. If the reaction is, however, habituated, a different response to the stimulus in undiminished strength may occur.

Let's take an example from everyday school life: During an exam, the teacher suddenly makes an announcement. For a brief moment we pause in our work and look forward. A moment later, we look back on our exam and continue to work, although still hear the announcement of the teacher to. Our response to the teacher ( looking up ) is thus habituated, but another ( paying attention to his words ) is unabated strong.

Temporal duration

There are two types of habituation in time duration of Habituationseffektes:

Long - term habituation

This effect persists over time at comparatively long. Take, for example, an abstract painting. Let's see this for the first time, we will devote a lot of attention and amazed look at the unusual presentation for a while. We see the image again later, we look back only briefly and are not surprised because we know it already. Our response has so habituated. This habituation is temporally long-lasting - even if we encounter the image after five weeks or more again, our response will be greatly reduced compared to the first sight.

Short - term habituation

This form of habituation is temporally relatively short -lasting. Example, if we visit a disco, we might interfere with the loud music in the beginning. Over time, this reaction is habituate and we are hardly aware of them the volume. Then we leave the disco for a few hours and then enter it again, this habituation will no longer exist and interfere with the volume us again. The Habituationseffekt is therefore of relatively short duration.

Short - term habituation is observed, for example, in Habituierungen of experimental animals to aversive stimuli such as electric shocks.

An essential characteristic of the short - term habituation in contrast to the long - term habituation is the spontaneous recovery effect. This consists in the recovery of the response of the habituation ( ie, in a fed undertaken magnitude of the response ) after a time-out. Time-out means that you no longer presents the organism after completion of habituation to a stimulus that stimulus for a certain period of time (eg, the rat for 24 hours in their home cage releases ). Provides you after this break the charm again represents, then the previously habituated response in stronger shape than at the conclusion of Habituationsphase occurs. This effect is known as spontaneous recovery.

Habituation as a problem of behavioral tests

As useful as the mechanism of habituation for animals and humans is affected so uncomfortable by it are often the behavioral scientist. In their experiments, they 're often just rely on their test animals repeatedly suspend certain stimulus patterns to formulate credible statements about the effect of a particular stimulus on their behavior. In planning the experiments, therefore, must always be taken to ensure that by sufficiently long intervals of time between repetitions of the experiments a result of the tests falsifying habituation of the test animals can be excluded with a sufficiently large safety.