Perceptual organization in schizophrenia.

A report of numerosity task was used in 2 experiments to examine the effect of inherent stimulus organization on the report accuracy of 2 S groups. Ss in each experiment were 10 schizophrenics and 10 drug abusing inpatients (controls). In both experiments, displays containing from zero to 6 lines were presented tachistoscopically. In Exp I, the lines appeared either alone or with noise elements (circles). When the lines appeared alone, schizophrenics and controls performed comparably. Their report accuracy decreased with increases in the number of lines. In the noise condition, the level of performance dropped only for schizophrenics. In Exp II, the stimulus arrays did not contain noise elements. Ss were given the task of reporting all the lines they saw. The perceptual organization of the arrays was manipulated by varying the similarity and proximity of the line elements. The performance of controls deteriorated as the organization of the arrays became more complex; schizophrenics were not affected by the organization. In fact, their average performance was significantly better than that of controls. Results of the 2 experiments are interpreted as evidence that schizophrenics' perceptual deficit lies in a failure to organize information at an early stage in processing. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual organization and precategorical acoustic storage.

Current views of precategorical acoustic storage (PAS) have been largely based on differences in the level of recall of terminal list items as a function of input modality and on experiments in which various types of suffixes are added to unstructured auditory lists. Experiments with grouped lists reveal that PAS can make a far more extensive contribution to serial recall. A series of four experiments investigated grouping effects in relation to existing accounts of consolidation, attentional selection, and auditory masking in PAS. Grouping effects obtained with very brief intralist pauses were inconsistent with the consolidation and masking hypotheses. Contrary to the attentional hypothesis, nontemporal grouping by voice or by spatial location was found to be as effective as grouping by extended pauses. When nontemporal methods of grouping were combined with intralist pauses, the two sets of grouping cues were no better than one, suggesting that list segmentation by pauses and by item attributes must be explained in terms of a single process. These results are discussed in the context of previous research that implies the existence of an auditory store with a capacity greater than previously attributed to PAS. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual organization of two-dimensional patterns.

The perceptual organization of image patterns is considered from 2 standpoints. First, a theoretical framework is presented from which computational models of perceptual organization can be constructed and tested. Second, a specific computational model for perceptual organization of line images is described. In this model, input images are first processed by a dense array of neurons that have properties consistent with recent analyses of single-neuron responses in primary visual cortex. Then, complex image structure is discovered by interleaved pattern-matching and grouping processes constrained by a generalized uniqueness principle. A series of 3-pattern grouping experiments was performed to test a restricted version of the model and to estimate critical parameters. Using the estimated parameters, an extended version of the model was tested by generating predictions for a series of "textbook" perceptual organization demonstrations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual organization in Alzhiemer's disease.

The ability of 16 AD patients and 16 age-matched control Ss to discriminate degraded forms was compared. Also examined were the effects of aging on perceptual organization by comparison of performance of normal Ss ranging in age from 20 to 86 years. Ss discriminated 2 forms, a circle and a square, each composed of randomly distributed dots concurrently embedded in visual noise. By means of a forced-choice procedure, the threshold signal-to-noise ratios at 4 levels of figure degradation were obtained, each presented at 3 durations. Performance by the normal Ss did not vary with age for long-duration stimuli, but did decline with age for briefly presented stimuli. Relative to age-matched control Ss, AD patients had significantly elevated thresholds at all form densities. Disruption of visual processing at the level of perceptual organization is likely a contributing factor to impairment of high-order visual function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual organization and intelligence: A further study.

This experiment was a replication of that of Krech and Calvin (Levels of perceptual organization and cognition. J. abnorm. soc. Psychol., 1953, 48, 394-400) using modified techniques. The correlation previously reported by Krech and Calvin between intelligence and perception, did not obtain upon replication. The data confirmed their finding that progression over trials was usually from low to high perceptual organization, but did not show a correlation between perception and stimulus-exposure time from 0.01 to 1.00 second. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychometric detection of schizotypy: Perceptual aberration and physical anhedonia in relatives of schizophrenics.

Administered scales of Perceptual Aberration (PERAB) and Physical Anhedonia (PHYSAN), traits that may be related to risk for schizophrenia, to 54 schizophrenics, 146 of their 1st-degree relatives (evaluated for schizophrenia-related disorders), and 178 normal Ss (screened for psychotic disorders in them or their relatives). For both scales, there was a significant effect of group membership. For the PERAB scale, the schizophrenics had higher scores than the normal Ss, who had higher scores than the relatives. For the PHYSAN scale, schizophrenics had higher scores than their relatives, who had higher scores than the normal Ss. Patterns of familial correlations also suggested that physical anhedonia, but not perceptual aberration, may be familial among schizophrenics and their relatives. The PHYSAN scale, but not the PERAB one, may be a useful indicator of liability for schizophrenia among the relatives of affected probands. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual organization of moving stimuli modulates the flash-lag effect.

When a visual stimulus is flashed at a given location the moment a second moving stimulus arrives at the same location, observers report the flashed stimulus as spatially lagging behind the moving stimulus (the flash-lag effect). The authors investigated whether the global configuration (perceptual organization) of the moving stimulus influences the magnitude of the flash-lag effect. The results indicate that a flash presented near the leading portion of a moving stimulus lags significantly more than a flash presented near the trailing portion. This result also holds for objects consisting of several elements that group to form a unitary percept of an object in motion. The present study demonstrates a novel interaction between the global configuration of moving objects and the representation of their spatial position and may provide a new and useful tool for the study of perceptual organization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual organization in schizophrenia: The processing of symmetrical configurations.

The hypothesis that the perceptual organization dysfunction of patients with poor premorbid schizophrenia is due to a deficit in global visual sensory store processing was tested by assessing their ability to process symmetrical configurations that develop early and have strong prepotent structures. Two same–different judgment tasks in which performance varies as a function of the symmetrical organization and task demands were administered to participants with good and poor premorbid schizophrenia, those with mood disorders, and normal controls. Like the other groups, poor premorbid schizophrenics' latency and error response patterns closely paralleled the a priori model of adequate processing. The results support their competence in perceptually processing symmetrical configurations and disconfirm the hypothesis that their input deficiencies represent a general deficiency in all forms of perceptual organization. The implications for specifying their early input dysfunction are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychometric schizotypy and motor performance.

Motor abnormalities have long been a focus in discussions of schizophrenia. The present study used a newly developed line drawing task to examine fine motor performance and psychometrically assessed schizotypy in a large, randomly ascertained sample of young adults (N = 120) with no history of psychosis. Poor motor performance on the line drawing task, indexed by root-mean-square error (RMS), was significantly related to 4 separate psychometric measures of schizotypy in the overall sample. The psychometric schizotypy-RMS association remained significant for 2 of the schizotypy measures even when the effects of intellectual functioning, mental state factors, and sustained attention were statistically controlled in a regression analysis. The status of the line drawing index as a schizophrenia liability measure is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychometric detection of schizotypy.

Genetic studies of typical schizophrenia require accurate means for the detection of carriers of the heritable diathesis. Psychometric methods have been developed, often for studying psychosocial transmission of schizophrenia, that might be useful for genetic studies. Studies of schizotypy detection using the Goldstein-Scheerer Object Sorting Test, Rorschach technique, TAT, and MMPI are reviewed. Most studies suffer from serious conceptual and methodological flaws that have made replication a rarity. Recent approaches emphasizing clinical signs and symptoms that bear a close content relationship to the typical schizophrenic syndrome are asserted to be more likely to bear fruit. (1? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual organization of behavior: A hierarchical control model of coordinated action.

Compared the behavior of 4 college students and 2 faculty members (including the present author) with a hierarchical control system model of behavioral organization. Ss varied the position of 2 control handles simultaneously to keep the distance constant between 2 pairs of lines. Three variations on this basic experiment that illustrate some fundamental properties of coordinated action showed (1) how independent actions, compensating for unpredictable and undetectable disturbances, can produce a single behavioral result; (2) how the ability to produce a particular result is maintained when the connection between action and result is changed; and (3) how 2 independent outputs can appear to be related as coordinative structures when one output disturbs a result being controlled by the other. The correlation between the behavior of Ss and the model in all experiments was typically on the order of .99. A detailed examination of the operation of the model demonstrated that actions are structured by perception, not by central commands or equations of constraint. (35 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Schizotaxia, schizotypy, schizophrenia.

"I hypothesize that the statistical relation between schizotaxia, schizotypy, and schizophrenia is class inclusion: All schizotaxics become on all actually existing social learning regimes, schizotypic in personality organization; but most of these remain compensated. A minority, disadvantaged by other… constitutional weaknesses, and put on a bad regime by schizophrenogenic mothers… are thereby potentiated into clinical schizophrenia. What makes schizotaxia etiologically specific is its role as a necessary condition… . It is my strong personal conviction that… schizophrenia, while its content is learned, is fundamentally a neurological disease of genetic origin." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual organization in schizophrenia: utilization of the Gestalt principles

BACKGROUND: Allergen immunotherapy results in a number of changes in clinical, inflammatory, and immunologic parameters. However, the basis for the specificity of this form of therapy is unknown, especially in the context of changes in T- and B-lymphocyte function after desensitization to specific allergens. OBJECTIVE: This study was designed to determine the immunologic consequences of rush immunotherapy. METHODS: We studied 10 patients who had positive skin test responses to the house dust mite Dermatophagoides pteronyssinus (Dpt) and cat dander extract. Each received rush immunotherapy to mite, but not cat dander, over a 2- to 4-week period until maintenance was achieved. Patients were evaluated before and when maintenance was achieved for skin test and nasal reactivity to mite and cat dander; antibody levels to the allergen were monitored, as were lymphocyte proliferative responses and cytokine production. RESULTS: Rush immunotherapy to house dust mite resulted in a significant reduction in skin and nasal reactivity to mite allergen, but not to cat allergen, in 10 of 10 patients. This was accompanied by a rise in serum anti-Dpt IgE, whereas anti-cat IgE was not altered (7 of 7 patients). In seven of seven patients there was an increase in anti-Dpt IgG4 levels. T-cell proliferative responses to mite antigen were suppressed, and numbers of CD8+ T cells increased in frequency. There was a marked increase in interferon-gamma production, particularly by CD4+ T cells in 10 of 10 patients. The correlation between the increases in interferon-gamma production and the changes in cutaneous reactivity was highly significant. CONCLUSION: We show that rush immunotherapy is immunologically specific in eliciting changes in T- and B-cell responses to the desensitization antigen. The specificity and potential benefit of immunotherapy may be linked to the increase in interferon-gamma production by allergen-activated CD4+ T lymphocytes.     

Perceptual organization of complex auditory sequences: Effect of number of simultaneous subsequences and frequency separation.

Previous findings on streaming are generalized to sequences composed of more than 2 subsequences. A new paradigm identified whether listeners perceive complex sequences as a single unit (integrative listening) or segregate them into 2 (or more) perceptual units (stream segregation). Listeners heard 2 complex sequences, each composed of 1, 2, 3, or 4 subsequences. Their task was to detect a temporal irregularity within 1 subsequence. In Experiment 1, the smallest frequency separation under which listeners were able to focus on 1 subsequence was unaffected by the number of co-occurring subsequences; nonfocused sounds were not perceptually organized into streams. In Experiment 2, detection improved progressively, not abruptly, as the frequency separation between subsequences increased from 0.25 to 6 auditory filters. The authors propose a model of perceptual organization of complex auditory sequences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thought disorder, perceptual aberrations, and schizotypy.

Empirical links between schizophrenia and schizotypic psychopathology were examined. The Perceptual Aberration Scale (PerAb; L. J. Chapman, J. O. Chapman, & M. L. Raulin; see record 1979-23733-001) was used to identify putative schizotypic individuals and a contrast group of nonschizotypic controls. The Thought Disorder Index (TDI; M. J. Coleman et al.; see record 1994-15942-001) was used to quantify and classify thought disorder in these individuals. High PerAb participants, selected for having an increased number of self-reported perceptual and body image aberrations, showed an elevation in the amount and frequency of thought disorder as well as an increased number of idiosyncratic verbalizations. This supports the hypothesis that psychometrically identified schizotypic individuals display thought disorder similar to that shown by schizophrenic patients and some of their 1st-degree relatives, suggesting that there is a relation between schizotypic psychopathology, as tapped by the PerAb scale, and clinical schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual noise and aging.

Presents evidence pertaining to the hypothesis that aging is characterized by a decrement in the ability to suppress irrelevant stimuli (perceptual noise). Although studies in the various sensory modalities generally support a perceptual noise hypothesis of aging, most of the evidence is marred by serious structural weaknesses. It is concluded that the heuristic value of such a unifying hypothesis seems, however, to justify further investigation aimed at correcting these flaws. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual orientation and empathy.

Administered an empathy scale and the Embedded Figures Test to 32 male undergraduates to explore the relationship between empathy, as an interpersonal affective variable, and psychological differentiation. As was predicted, empathy was significantly correlated with perceptual orientation (p     

Perceptual organization of acoustic stimuli by budgerigars (Melopsittacus undulatus): I. Pure tones.

A new combination of operant conditioning and psychophysical scaling procedures was used to study auditory perception in a small bird. In a same–different discrimination task, budgerigars learned to discriminate among pure tones that varied along one or more acoustic dimensions. Response latencies were used to generate a matrix of interstimulus similarities. Multidimensional scaling procedures were used to arrange these acoustic stimuli in a multidimensional space that supposedly reflects the bird's perceptual organization. For tones that varied in intensity, duration and frequency simultaneously, budgerigars were much more sensitive to frequency changes. From a set of tones that varied only in intensity, it was possible to calculate the growth of loudness with intensity for the budgerigar. For tones that varied only in frequency, budgerigars showed evidence of an "acoustic fovea" for frequency change in the spectral region of 2–4 kHz. Budgerigars and humans also differed in their perceptual grouping of tone sequences that rise, fall, or remain constant in pitch. Surprisingly, budgerigars were much less responsive to pitch contour than were humans. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual organization of acoustic stimuli by budgerigars (Melopsittacus undulatus): II. Vocal signals.

Operant conditioning and multidimensional scaling procedures were used to study auditory perception of complex sounds in the budgerigar. In a same–different discrimination task, budgerigars learned to discriminate among natural vocal signals. Multidimensional scaling procedures were used to arrange these complex acoustic stimuli in a two-dimensional space reflecting perceptual organization. Results show that budgerigars group vocal stimuli according to functional and acoustical categories. Studies with only contact calls show that birds also make within-category discriminations. The acoustic cues in contact calls most salient to budgerigars appear to be quite complex. There is a suggestion that the sex of the signaler may also be encoded in these calls. The results from budgerigars were compared with the results from humans tested on some of the same sets of complex sounds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual organization of acoustic stimuli by budgerigars (Melopsittacus undulatus): III. Contact calls.

We trained budgerigars by operant conditioning to discriminate among a set of contact calls in a same–different task and analyzed response latencies from this task by using multidimensional-scaling (MDS) and cluster-analysis procedures. Humans listened to the same calls and indicated the similarity between pairs of calls by a direct rating procedure. An MDS program ({sindscal}) was used to arrange these complex acoustic stimuli in multidimensional space reflecting perceptual organization. Multiple regression techniques were used to identify the acoustic characteristics of contact calls that were correlated with the peceptual dimensions obtained from MDS. A number of spectral characteristics (e.g., peak frequency, rate of frequency modulation, and concentration of spectral energy) emerged as important for both budgerigars and humans, but the relative salience of these cues differed for the two species. Additional tests with two groups of budgerigars—cagemates and noncagemates—showed that experience with calls can change the salience of various acoustic characteristics used for perceptual organization and individual recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)