Clinical correlates of anhedonia and perceptual aberration in first-episode patients with schizophrenia and affective disorder.

We examined the association between scales measuring physical anhedonia, social anhedonia, and perceptual aberration and premorbid functioning, clinical state, and current level of adjustment in 91 psychotic subjects. The patients were examined at the onset of their first psychotic episode and again 18 months later. For patients with schizophrenia, anhedonia was significantly related to premorbid functioning. No association was found between the scales and clinical state or level of adjustment at intake or follow-up. In affective disorder patients, no correlation was found between premorbid functioning (a stable characteristic) and scale scores, but moderately large correlations emerged between the scales and clinical state and level of adjustment at both assessment times. These results suggest that schizophrenic and affective disorder patients endorse items on these scales for different reasons. We hypothesize that for patients with schizophrenia, the scales assess enduring personality characteristics, whereas for the affective disorder patients, they assess clinical condition at the time of testing.     

Anhedonia and perceptual aberration in first-episode psychotic patients and their relatives

One hundred eighteen psychiatric patients, each experiencing his or her first lifetime episode of psychosis, 125 of their first-degree relatives, and 155 normal subjects were assessed using the physical anhedonia, social anhedonia, and perceptual aberration scales of Chapman et al. (1976, 1978). We hypothesized that psychotic subjects would obtain higher scores on these scales than their relatives and the controls, and we expected the group of relatives to score more deviantly than the normal controls. The physical anhedonia and social anhedonia scales successfully differentiated the psychiatric patients from the relatives and the latter from the normal subjects. These findings testify to the construct validity of the scales and suggest that they tap a predisposition to psychosis. Unexpectedly, the relatives scored lower on the perceptual aberration scale than did the normal controls, perhaps because the relatives adopted a defensive response set.     

Hedonic capacity and schizotypy revisited: a taxometric analysis of social anhedonia

P. E. Meehl (1962) originally conjectured that hedonic capacity was an indicator of the latent class or taxon of schizotypy. However, P. E. Meehl (1989, 1990) subsequently diminished the role of hedonic capacity in his theory, indicating that hypohedonia is one of a dozen normal-range (nontaxonic) individual-differences factors that may potentiate the expression of schizophrenia. This dimensional-only view of hedonic capacity was tested by applying taxometric procedures to the Revised Social Anhedonia Scale (RSAS; M. L. Eckblad, L. J. Chapman, J. P. Chapman, & M. Mishlove, 1982) in a sample of college students (N = 1,526). Analyses indicated that the construct measured by the RSAS is taxonic in nature with a base rate approximating .10. These data are interpreted in the context of other findings suggesting that social anhedonia is an indicator of schizotypy.     

On "risk" and reward: investigating state anhedonia in psychometrically defined schizotypy and schizophrenia

Anhedonia, defined as dysfunction in the experience of pleasant emotions, is a hallmark symptom of the schizophrenia spectrum. Of interest, it is well documented that patients with schizophrenia, at least as a group, do not show reductions in their state experience of pleasant stimuli. However, there is emerging evidence to suggest that individuals with schizotypy--defined as the personality organization reflecting the latent vulnerability for schizophrenia--do show these state deficits. This is paradoxical in that schizophrenia reflects a more pathological state in virtually every conceivable domain as compared with schizotypy. The present study examined self-reported affective reactions to neutral-, bad-, and good-valenced stimuli in individuals with psychometrically defined schizotypy and schizophrenia. Two separate control groups were also included, comprising psychometrically defined controls and stable outpatients with affective disorders. With no exceptions, the schizotypy group reported significantly less pleasant affect for each of the three conditions than each of the other groups. Conversely, the schizophrenia group did not statistically differ from the control groups for any of the conditions. Within both the schizotypy and schizophrenia groups, severity of negative symptoms/traits was associated with less pleasant report. We found that individuals with prominent negative symptoms and traits from the schizophrenia and schizotypy groups resembled each other in terms of state anhedonia. The present findings did not appear to reflect comorbid depression or anxiety. Our discussion centers on this apparent paradox in the schizophrenia spectrum--that individuals with schizotypy exhibit state anhedonia, whereas patients with schizophrenia do not.     

Culture and the physical environment. Holistic versus analytic perceptual affordances

Westerners' perceptions tend to focus on salient foreground objects, whereas Asians are more inclined to focus on contexts. We hypothesized that such culturally specific patterns of attention may be afforded by the perceptual environment of each culture. In order to test this hypothesis, we randomly sampled pictures of scenes from small, medium, and large cities in Japan and the United States. Using both subjective and objective measures, Study 1 demonstrated that Japanese scenes were more ambiguous and contained more elements than American scenes. Japanese scenes thus may encourage perception of the context more than American scenes. In Study 2, pictures of locations in cities were presented as primes, and participants' subsequent patterns of attention were measured. Both Japanese and American participants primed with Japanese scenes attended more to contextual information than did those primed with American scenes. These results provide evidence that culturally characteristic environments may afford distinctive patterns of perception.     

Strategies for resolving the heterogeneity of schizophrenics and their relatives using cognitive measures

The resolution of the heterogeneity of schizophrenics and their relatives using cognitive tasks requires measures of individual differences--usually of differential ability, which is inferred from differential performance. Tasks that are suited for establishing a group's differential ability are often unsuited for measuring individual differences. The problem is that for any group for which Tasks A and B have different mean accuracy, the (A - B) difference scores of individual subjects have an artifactual curvilinear relation to (A + B) overall accuracy, with the largest (A - B) scores occurring at about 50% (A + B) overall accuracy for a dichotomously scored free-response task. Two possible solutions are (a) to convert Task B scores to residualized scores, using the regression of Task B scores on Task A scores as determined for normal subjects; or (b) to titrate overall (A + B) accuracy of each subject to a constant level by manipulating a variable.     

Visual detection and perceptual independence: Assessing color and form

Visual stimuli are multidimensional. One important perceptual problem is to determine how the dimensions are combined. One important aspect of dimensional combination is whether the dimensions are perceptually independent or perceptually correlated. A new task is presented—the visual detection task—that directly assesses the degree of perceptual correlation between any two dimensions. Two experiments were conducted that assess the degree of perceptual correlation between form and color during the early stages of perceptual analysis. The results show that form and color are not perceptually independent. In addition, the pattern of perceptual correlation found indicates that form and color are not processed independently. The pattern of results constrains all models of early vision. A model of early vision based on active signal modulation is proposed.     

Early stimulus processing in dysthymia and anhedonia.

Previous event-related brain potential (ERP) research has found that dysthymic subjects differ from control subjects during later stages of information processing. An important issue that emerges from this literature is whether differences found in these ERP components, typically associated with cognitive processing, can be attributed to earlier differences in basic perceptual processing. This study was undertaken to determine whether early processing deficits are apparent in dysthymic persons. Responses of dysthymics (n = 23) were compared with those of anhedonic (n = 15) and normal control (n = 17) subjects. ERPs were recorded while subjects heard tones at 55, 65, 75, 85, and 95 dB. Overall, N1-P1 and N1-P2 components of the ERP increased in a strong linear fashion as stimulus intensity increased. Dysthymics did exhibit a smaller N1-P2 response than normal subjects, which suggests the presence of difficulties in initial perceptual processing.     

Psychometric functions and a correlation model of binaural detection

Sets of psychometric functions for the detection of tone in noise are reexamined for several interaural listening conditions. Best-fit sets of functions are determined for a “correlation” model of binaural masking level differences (MLDs). Based on only three parameters, this model predicts both the forms and relative positions of all such functions. The finding that MLDs are relatively independent of the detection level chosen for their determination is predicted by the model, and the sets of theoretical functions describe the data nearly as well as a previously determined empirical relation which requires M + 1 parameters for M curves.     

Feature sampling in detection: implications for the measurement of perceptual independence

The article presents the feature sampling signal detection (FS-SDT) model, an extension of the multivariate signal detection (SDT) model. The FS-SDT model assumes that, because of attentional shifts, different subsets of features are sampled for different presentations of the same multidimensional stimulus. Contrary to the SDT model, the FS-SDT model enables the estimation of pure perceptual effects that are uncontaminated by strategic attention shifts. The consideration of feature sampling in detection and identification opens a new perspective on the problem of measuring, respectively, the separability and integrality of stimulus dimensions. Disregarding feature sampling as a component process in detection and identification usually results in biased estimations of perceptual independence concepts relevant for judgments of whether stimulus dimensions are processed independently.     

The role of attentional breadth in perceptual change detection

Previous research has shown that changes to scenes are often surprisingly hard to detect. The research reported here investigated the relationship between individual differences in attention and change detection. We did this by assessing participantś breadth of attention in a functional field of view task (FFOV) and relating this measure to the speed with which individuals detected changes in scenes. We also examined how the salience, meaningfulness, and eccentricity of the scene changes affected perceptual change performance. In order to broaden the range of individual differences in attentional breadth, both young and old adults participated in the study. A strong negative relationship was obtained between attentional breadth and the latency with which perceptual changes were detected; observers with broader attentional windows detected changes faster. Salience and eccentricity had large effects on change detection, but meaning aided the performance of young adults only and only when changes also had low salience.     

The revised perceived locus of causality in physical education scale: Psychometric evaluation among youth

Objectives

Given instances of less than optimal internal consistency levels of the Perceived Locus of Causality (PLOC) scale when applied to school-based physical education (PE), the aim of the study was to examine the psychometrics of a revised PLOC instrument for use in PE.

Design

A cross-sectional study in which self-report data on behavioral regulations, perceived autonomy support by the PE teacher, and subjective vitality were collected from 1729 students in relation to their PE participation at the elementary school (5th and 6th grade), middle school, and high school levels, including boys and girls.

Results

The revised instrument (PLOC-R) demonstrated satisfactory levels of internal consistency; a sound factor structure; evidence in support of a simplex-like structure; configural, metric, strong, and strict measurement invariance across boys and girls, students who participate or not in out-of-school sport activities, and across the three school grade levels; and nomological validity.

Conclusions

Initial evidence has emerged in favor of the PLOC-R as a scale appropriate for use with 5th and 6th grade elementary, middle school, and high school students to measure the degree of self-determined motivation for participation in compulsory school-based physical education classes.     

The unilateral field advantage in repetition detection: Effects of perceptual grouping and task demands

This study examines interhemispheric interactions in detecting objects that are simultaneously repeated in an array of objects. Previous studies have shown that presenting two identical objects to a single hemifield speeds up repetition detection. This unilateral field advantage (UFA) is often attributed to the relatively low-level processing demands for detecting a perceptual repetition, and more specifically, to more efficient perceptual grouping processes within a hemisphere than between hemispheres. To directly examine the impact of perceptual grouping and task demands on interhemispheric interactions, we asked participants to judge whether four items, one presented in each visual quadrant, were all different, or whether any two were the same, along an instructed dimension. We found that in comparison with the UFA for identical objects, the UFA for repetition detection in accuracy was similar or greater when the matching objects were not perceptually identical and differed in color, size, or viewpoint. Thus, decreasing grouping strength and increasing computational complexity did not reduce the UFA. Results are interpreted in terms of the callosal degradation account of the UFA.     

Change detection in complex scenes: hemispheric contribution and the role of perceptual and semantic factors

The perceptual salience and semantic relevance of objects for the meaning of a scene were evaluated with multiple criteria and then manipulated in a change-detection experiment that used an original combination of one-shot and tachistoscopic divided-visual-field paradigms to study behavioural hemispheric asymmetry. Coloured drawings that depicted meaningful situations were presented centrally and very briefly (120 ms) and only the changes were lateralised by adding an object in the right or in the left visual hemifield. High salience and high relevance improved both response times (RTs) and accuracy, although the overall contribution of salience was greater than that of relevance. Moreover, only for low-salience changes did relevance affect speed. RTs were shorter when a change occurred in the left visual hemifield, suggesting a right-hemisphere advantage for detection of visual change. Also, men responded faster than women. The theoretical and methodological implications are discussed.     

Increasing specificity in perceptual development: infants' detection of nested levels of multimodal stimulation

This research assessed the development of infants' sensitivity to two nested amodal temporal relations in audible and visible events. Their detection of global temporal synchrony between visible and audible impacts and internal temporal structure nested within each impact specifying object composition (single versus compound objects) was assessed. Infants of 4, 7, and 11 weeks of age were habituated to a single and a compound object striking a surface and then received test trials depicting a change in synchrony or object composition. Results indicated an interaction between age and condition where sensitivity to synchrony was present by 4 weeks and remained stable across age, whereas sensitivity to composition emerged later, by 7 weeks, and increased dramatically with age. These findings converge with other recent findings to illustrate a pattern of increasing specificity in the development of perception, where infants first detect global and later detect embedded relations. The early sensitivity to global relations may provide an organizational framework for development by focusing infant attention on unitary events, guiding and constraining further exploration, and buffering infants from learning incongruent relations.     

Semantic consistency versus perceptual salience in visual scenes: Findings from change detection

In a one-shot change detection task, we investigated the relationship between semantic properties (high consistency, i.e., diagnosticity, versus inconsistency with regard to gist) and perceptual properties (high versus low salience) of objects in guiding attention in visual scenes and in constructing scene representations. To produce the change an object was added or deleted in either the right or left half of coloured drawings of daily-life events. Diagnostic object deletions were more accurately detected than inconsistent ones, indicating rapid inclusion into early scene representation for the most predictable objects. Detection was faster and more accurate for high salience than for low salience changes. An advantage was found for diagnostic object changes in the high salience condition, although it was limited to additions when considering response speed. For inconsistent objects of high salience, deletions were detected faster than additions. These findings may indicate that objects are primarily selected on a perceptual basis with subsequent and supplementary effect of semantic consistency, in the sense of facilitation due to object diagnosticity or lengthening of processing time due to inconsistency.     

Confirming the latent structure and base rate of schizotypy: a taxometric analysis.

Meehl's (1962, 1990) model of schizotypy and the development of schizophrenia implies that the structure of liability for schizophrenia is dichotomous and that a "schizogene" determines membership in a latent class, or taxon (Meehl & Golden, 1982). The authors sought to determine the latent structure and base rate of schizotypy. They applied Meehl's (1973; Meehl & Golden, 1982) MAXCOV-HITMAX taxometric analytic procedures to a subset of items from the Perceptual Aberration Scale (PAS; Chapman, Chapman, & Raulin, 1978), a prominent psychometric index of schizotypy, derived from a randomly ascertained nonclinical university sample (N = 1,093). The results, in accordance with Meehl's conjectures, strongly suggest that schizotypy, as assessed by the PAS, is taxonic at the latent level with a general population taxon base rate of approximately .10.     

Self-repair in dialogues of schizophrenics: effects of hallucinations and negative symptoms.

This paper concerns the discourse features of verbal hallucinations and negative symptoms of schizophrenia. A total of 46 schizophrenics, varying in verbal hallucination and in negative symptoms status, and 22 controls were tested on the Reporter Test. The frequency with which they issued inadequate instructions, attempted to repair the inadequacies, and the success of repairs were compared. We observed that schizophrenics, on the whole, issued more wrong and incomplete instructions. This was in part related to their worse working memory, but it was not affected by verbal hallucinations or negative symptoms. We observed, further, that schizophrenics had no particular problems monitoring messages for inadequacies. We did find, however, that schizophrenics with verbal hallucinations had a specific problem with self-repairing wrong instructions. We interpret these results in the framework of Hoffman's (1986b) plan disruption-based model of verbal hallucinations; the Frith (1987) and Frith and Done (1988) internal monitoring model of positive and negative symptoms; and finally Frith and Frith's (1990) model of negative and positive schizophrenia and we use the results to specify the models.     

Multielement visual tracking: attention and perceptual organization.

Two types of theories have been advanced to account for how attention is allocated in performing goal-directed visual tasks. According to location-based theories, visual attention is allocated to spatial locations in the image; according to object-based theories, attention is allocated to perceptual objects. Evidence for the latter view comes from experiments demonstrating the importance of perceptual grouping in selective-attention tasks. This article provides further evidence concerning the importance of perceptual organization in attending to objects. In seven experiments, observers tracked multiple randomly moving visual elements under a variety of conditions. Ten elements moved continuously about the display for several seconds; one to five of them were designated as targets before movement initiation. At the end of movement, one element was highlighted, and subjects indicated whether or not it was a target. The ease with which the elements in the target set could be perceptually grouped was systematically manipulated. In Experiments 1-3, factors that influenced the initial formation of a perceptual group were manipulated; this affected performance, but only early in practice. In Experiments 4-7, factors that influenced the maintenance of a perceptual group during motion were manipulated; this affected performance throughout practice. The results suggest that observers spontaneously grouped the target elements and directed attention toward this coherent but nonrigid virtual object. This supports object-based theories of attention and demonstrates that perceptual grouping, which is usually conceived of as a purely stimulus-driven process, can also be governed by goal-directed mechanisms.