Latent inhibition and context change in psychometrically defined schizotypy (original) (raw)
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Personality and Individual Differences, 2003
Two experiments examined the effects of schizotypy (STA) on performance in a visual search of fast moving words. Accuracy was examined as a function of prior experience with the target. The reported studies sought to demonstrate a latent inhibition (LI) effect that does not depend on the target/distractor reversal that has been so far employed in the human studies. Two target conditions were examined (PE: target pre-exposed presented with novel distactors; NPE: target novel presented with novel distractors). In experiment 1 (N=60), lower accuracy rate in the PE than in the NPE condition was obtained, but a disruption of this LI effect was found for high schizotypy scorers. In experiment 2 (N=61), the same procedure was repeated, but with the double amount of target pre-exposure. Latent inhibition was found to be disrupted in high schizotypy scorers, but was intact in low schizotypy scorers. The amount of pre-exposure facilitated overall performance, but had no effect on latent inhibition. The amount of pre-exposure, nevertheless, had an effect on the temporal manifestation of the phenomenon across the blocks of trials of the testing phase. #
Psychonomic Bulletin & Review, 2005
Latent inhibition (LI) is a robust phenomenon that is demonstrated when a previously inconsequential stimulus is less effective in a new learning situation than a novel stimulus. Despite LI’s simplicity, there is considerable disagreement as to its theoretical basis. Attentional theories claim that unattended stimulus preexposures reduce stimulus associability. Alternatively, it has been asserted that associability is unaffected and that LI is a result of competition/retrieval processes. The present article reviews a series of visual search studies, some with normal subjects, both undifferentiated and divided into low and high schizotypals, and others with pathologies that entail dysfunctional attention, such as schizophrenia, Parkinson’s disease, and anxiety. The visual search conditions were designed to model those of traditional LI experiments, while tapping attentional processes independently of the learning scores that index LI. A variety of evidence from these and other studies is used to support the involvement of attentionaland retrieval processes in LI. A model of the mechanism of action of these processes in LI is presented, together with its application to schizophrenia.
Personality and Individual Differences, 2009
Latent inhibition (LI) refers to poorer learning for a previously exposed, irrelevant stimulus (PE) than for a non-preexposed, novel stimulus (NPE). According to recent theoretical accounts of this phenomenon, positive schizotypal symptoms should attenuate LI while negative symptoms should produce a persistent LI. To test this prediction, non-clinical participants (N = 115), randomly allocated to either PE or NPE group, performed a visual-search LI task and completed psychometric measures of schizotypy. Overall, fewer correct responses in the PE group than in the NPE group suggested a LI effect. Subsequent regression analyses showed that in the PE group positive schizotypy was associated with attenuated LI whereas negative schizotypy was associated with enhanced LI. To the best of our knowledge, this study provides the first evidence for a bi-directional model of LI modulation in schizotypy.
Latent Inhibition and Psychometrically Defined Schizotypy: An Experimental Investigation
The thesis adopted a personality-based approach to experimental psychopathology testing alternative interpretations of latent inhibition deficits as a function of psychotic-like features in non-clinical participants. Chapter 1 reviews the evidence on the continuity of psychotic-like experiences, describes the historical origins of dimensional views of psychosis, and discusses methodological advantages and pitfalls in schizotypy research.
Schizophrenia Research, 2002
Two experiments examined the visual search analog of latent inhibition (LI) and the novel popout (NPO) effect in healthy humans. In Experiments 1 (n 48) and 2 (n 180), subjects judged the positions (left or right side of a computer screen) of a unique target amongst a ®eld of homogeneous distractors. In both experiments, there was a strong LI effect, as indicated by longer response times (RT) to those displays in which the target was previously a distractor and the distractors were previously the target, as compared with displays in which the target was novel and the distractors were previously the target. NPO, faster RT to a display in which the target was novel on a background of familiar distractors than to a display in which both target and distractors were novel, was not obtained. In Experiment 1, LI magnitude was not affected by gender. In Experiment 2, LI magnitude was larger for low schizotypal females than for high schizotypal females, a result not obtained for males. This pattern is similar to one reported for medicated schizophrenic out-patients (Lubow, R.E., Kaplan, O., Abramovich, P., Rudnick, R., Laor, N., 2000. Visual search in schizophrenics: latent inhibition and novel popout effects. Schizophr. Res., in press). Together, these data suggest that the LI de®cits found in high schizotypal healthy subjects and in schizophrenic patients represent a dysfunction that is characterized by an inability to reduce attention allocated to irrelevant stimuli, and that this may serve as a trait marker for some subtypes of schizophrenia, particularly those associated with female gender. q
Latent inhibition as a function of schizotypality and gender: implications for schizophrenia
Biological Psychology, 2002
In three within-subject experiments, we demonstrated that preexposure to an irrelevant stimulus interfered with performance when that stimulus subsequently predicted the correct location of a target stimulus. This latent inhibition-like effect (LI) was manifest in response time measures, but not errors. As with other related paradigms, LI was a function of an interaction between schizotypy-level and gender. Low schizotypal females and high schizotypal males exhibited significant LI, while high schizotypal females and low schizotypal males failed to produce LI effects. The results, similar to findings with schizophrenic patients, suggest a sexual dimorphism of cognitive dysfunction in schizophrenia, particularly in regard to the processing of irrelevant stimuli.
Clinical features of latent inhibition in schizophrenia
Schizophrenia Research, 2001
Paradigms of Latent Inhibition (LI) are inter-species and derived from learning theories. They are considered as tools which allow the attentional processes to be studied. The absence of LI is interpreted as dif®culty in discriminating relevant and irrelevant stimuli. Abolition of LI has been shown in acute schizophrenics. The objectives of our study were partly to validate an LI paradigm, based on a contingency detection between two stimuli, in healthy subjects, and partly to analyse LI in schizophrenics. The study included 105 subjects (65 patients and 40 controls). Patients ful®lled the DSM IV diagnosis of schizophrenia. 35 in the acute phase and 30 in the chronic phase. We observed a loss of LI for acute schizophrenics, and an enhancement of LI for chronic schizophrenics. The variations in LI are interpreted from the perspective of a disturbance in the attentional processes. The LI status in acute schizophrenics appears to correlate with the clinical criteria with a prognostic value (low intensity of the negative dimension, late age at the ®rst hospitalization). Moreover, the enhancement of LI correlates with the negative dimension of schizophrenic disease. This correlation is found in acute and chronic schizophrenics. It suggests that the variations of LI may be an indicator of adaptive strategies to a cognitive dysfunction speci®c to schizophrenia. q 2001 Elsevier Science B.V. All rights reserved.
Schizotypy and latent inhibition: non-linear linkage between psychometric and cognitive markers
Personality and Individual Differences, 2001
Auditory latent inhibition (LI) and schizotypy were measured in (n=54), showing that LI was an inverted-U function of schizotypy score. Only average levels of schizotypy were associated with undiminished LI while both low-and high-SPQ subjects showed reduced LI. No relationship was found between LI and either psychoticism or any of the ®ve NEO PI-R domains. These results complement the similar complex relationship of neuroleptic drug dose eects on LI in normals and schizophrenics. A priming task and the unusual uses and pattern meanings measures of creativity were related to personality measures of schizotypy, N, E, and O (but not the EPQ-R psychoticism, LI, or priming performance). Priming eects tracked the inverted-U function of schizotypal personality questionnaire (SPQ) scale scores shown in the LI task. It is suggested that LI is dependent on a non-linear interaction with masking task load and attentional allocation, modulated by schizotypy. #
The relation between latent inhibition and symptom-types in young schizophrenics
Behavioural Brain Research, 2004
Latent inhibition (LI), retarded conditioning to a stimulus that has been previously repeatedly presented without reinforcement, was examined in young schizophrenics and normal controls using a within-subject visual search task. Healthy controls exhibited the usual LI effect. LI was potentiated in schizophrenics who simultaneously exhibited high levels of negative symptoms and low levels of positive symptoms. Schizophrenic groups with other combinations of positive and negative symptoms did not differ from controls. The pattern of data suggests that past inconsistencies in the LI-schizophrenia literature may be the result of opposing processes that are associated with positive and negative symptoms.
Visual search in schizophrenia: latent inhibition and novel pop-out effects
Schizophrenia Research, 2000
A visual search task was used to assess attentional function in a mixed group of schizophrenic patients and in normal controls. Subjects identified presence or absence of a unique shape presented with homogeneous distractors. Response time (RT ) was examined as a function of prior experience with target, distractor, or both. On each trial, targets and/or distractors were either novel or familiar. Schizophrenic patients were slower than controls in all conditions. In the test phase, three target/distractor conditions were examined (PE -target and distractors preexposed but reversed; NPE -target novel and distractors pre-exposed; NOV -novel target and distractors). As predicted, normal controls, but not schizophrenics, showed latent inhibition (LI: PE minus NPE ). The latter finding was due to the absence of normal LI in female patients. A novel pop-out effect (NOV minus NPE ) was obtained which did not interact with any of the other variables. The results suggest that the LI effect is indeed related to the processing of irrelevant stimuli, and that, at least female schizophrenic patients process such stimuli differently from controls. Past inconsistencies in the LI-schizophrenia literature may be the result of disproportionate gender compositions in patient and control groups.