Habituation A History theory of habituation Experimental studies

Habituation: A History

theory of habituation. . Experimental studies, or at least observations of phenomena of habituation for a variety of responses in a wide range of organisms from amoebas to humans literally exploded at the end of the nineteenth century and early twentieth century.

Humphrey (1933) notes that a range of terms, “accommodation, ” “negative adaptation, ” “fatigue” have been used to describe the phenomenon. Harris (1943) in his classic review adds the terms “extinction” and “stimulatory inactivation” to the list.

the restoration of an habituated response by extraneous stimulation, was early studied by Holmes (1912) in the sea urchin. Humphrey (1933) provides an example with human infants

DE habituation by lapse of time and by another stimulus are thus fundamentally the same, for they involve each of them the derangement of an established state of equilibrium by altered conditions, the alteration being one of increase of environmental energy in the one case, of decrease in the other.

habituation and dishabituation constitute basic information-processing skills. habituation-dishabituation paradigm presents a promising approach in the diagnosis of cognitive status and delay in development in preterm infants.

§ A creature that was unable to habituate to insignificant stimuli would probably have a difficult time attending to more important stimuli. In fact, there is some evidence that the rate of habituation in human infants and children is correlated with mental abilities later in life.

§ Laucht, Esser, and Schmidt (1994) found that infants who displayed faster habituation to repetitive stimuli at 3 months of age obtained, on average, slightly higher scores on intelligence tests when they were 4½ years old.

§ Another study found that adolescents who showed very slow habituation to repetitive stimuli had a higher risk of developing the severe psychiatric disorder schizophrenia later in life (Hollister, Mednick, Brennan, & Cannon, 1994).

information-processing skills § a habituation stimulus is presented to the infant for either one long period or several short periods (often equal to durations of infants’ individual looks). afterwards, that is in the post habituation or dishabituation period, a novel stimulus is shown. It is expected that the infant’s attention to the habituation stimulus will decline during the habituation phase, but will afterward increase to the novel stimulus.

§ these two patterns of responding are assumed to reflect information processing. During the habituation phase, the infant’s attention to the habituation stimulus wanes as the infant constructs a mental representation of the stimulus and the stimulus becomes less novel or interesting.

§ If the infant’s attention is reactivated by the novel stimulus, that is if the infant recovers attention, the inference is made that the infant compared the novel stimulus with the mental representation (memory) of the habituation stimulus, and so remembered the one and discriminated the other.

§ If the infant prefers to look at the novel stimulus, that is if the infant displays a novelty preference, the inference is made that the infant recognizes the habituation stimulus and detects a difference between the stimuli. This performance also indicates the infant’s recognition memory of the habituation stimulus.

§ the ideas that habituation must involve the construction of a mental representation or memory trace of the habituation stimulus and dishabituation the successful discrimination between this memory trace and a novel stimulus. habituation and dishabituation are two basic psychometric criteria.

§ habituation and dishabituation are characterized by adequate individual variation. From a qualitative view, some infants show a linear or exponential decrease in habituation (to a learning criterion); other infants first increase then decrease looking; and still other infants show a fluctuating looking pattern. § Similarly, infants show substantial individual variation in dishabituation

§ habituation and dishabituation can be expected to vary with state and age of the child, stimulus used, and so forth.

§ Successful habituation minimally implies neurologic integrity and sensory competence in the infant. Beyond that, habituation represents an elementary kind of no associative learning

§ The cognitive information-processing interpretation of habituation-dishabituation makes several straightforward predictions: § First, on an information-processing interpretation older and more mature babies ought to habituate more efficiently than younger and less mature babies

§ The second prediction of an informationprocessing interpretation is related to the first: Normally developing babies habituate and dishabituation more efficiently than babies born at-risk for cognitive developmental delay.

§ Children with Down syndrome or brain damage (e. g. , micro- or anencephalia) either fail to habituate and dishabituate or habituate and dishabituate relatively inefficiently (Hepper & Shahidullah, 1992; Lester, 1975), as do infants who have been exposed in utero to cocaine or alcohol

§ The third information-processing prediction is that infants ought to habituate to “simpler” stimuli more efficiently than to more “complex” stimuli.

§ Fourth, if habituation involves processing information, infants habituated to one stimulus should later be able to distinguish a novel stimulus in comparison with their internal mental representation of the now familiar stimulus.

§ Schizophrenia has long been associated with abnormal patterns of arousal that are thought to reflect disturbances in the reticular-activating system of the brain

Reduced habituation in patients with schizophrenia § habituation, is a basic form of learning. There is strong evidence for behavioral and physiological habituation deficits in schizophrenia, and one previous study found reduced neural habituation within the hippocampus.

§ However, it is unknown whether neural habituation deficits are specific to faces and limited to the hippocampus. Here we studied habituation of several brain regions in schizophrenia, using both face and object stimuli. Post-scan memory measures were administered to test for a link between hippocampal habituation and memory performance.

METHODS: § During an f. MRI scan, 23 patients with schizophrenia and 21 control subjects viewed blocks of a repeated neutral face or neutral object, and blocks of different neutral faces and neutral objects. Habituation in the hippocampus, primary visual cortex and fusiform face area (FFA) was compared between groups. Memory for faces, words, and word pairs was assessed after the scan.

§ CONCLUSION: § Patients with schizophrenia showed reduced habituation of the hippocampus and visual cortex, and a lack of neural discrimination between old and new images in the hippocampus. .

§ Hippocampal discrimination correlated with memory performance, suggesting reduced habituation may contribute to the memory deficits commonly observed in schizophrenia

§ These studies replicate previous findings of habituation in schizophrenia and provide further evidence for sensory reactivity disturbances in schizophrenia. Schizophrenia has long been associated with abnormal patterns of arousal to stimuli (Venables, 1966), which are thought to reflect disturbances in a well-described brain system

§ Slower rates of habituation are predicted to characterize schizophrenic patients, all of whom show a chronic disease course.