Latent inhibition and context change in psychometrically defined schizotypy

The disruption of latent inhibition within the schizophrenia spectrum has often been interpreted either as a result of increased attentional distractibility (attentional account) or as a result of deficient interference of past associations (associative account). The aim of the present investigation was to test competing predictions, as derived from the above theoretical accounts. In a visual search paradigm of latent inhibition, accuracy was examined as a function of prior experience with the target, and psychometrically defined schizotypy. In Experiment 1 (N=60), no context change was introduced. In accord with past evidence, latent inhibition was found to be intact in low-, but disrupted in high-schizotypy scorers, a result predicted both by attentional and associative accounts. In Experiment 2 (N=60), a context change was introduced. As predicted by past evidence, latent inhibition was disrupted in low-schizotypy scorers. However, latent inhibition was found to be intact in high-schizotypy scorers, a finding accommodated by attentional, but not associative accounts. Theoretical implications and alternative interpretations are also considered.     

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.     

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

We 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 first-degree relatives (evaluated for schizophrenia-related disorders), and 178 normal subjects (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 subjects, 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 subjects. 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.     

Response inhibition and interference control: Effects of schizophrenia,genetic risk,and schizotypy

The ability to inhibit inappropriate responses and suppress irrelevant information is a core feature of executive control. In this study, we provide a detailed analysis of prepotent response inhibition and interference in patients with schizophrenia. To further test the role of genetic factors and subclinical schizophrenia‐like traits, we additionally studied clinically unaffected, first‐degree relatives of schizophrenia patients and assessed dimensions of schizotypy in both relatives and healthy controls. Inhibition and interference control were assessed using a battery comprising the antisaccade, Stroop, stop signal, go/no‐go, flanker, and Simon tasks. Schizophrenia patients differed from both relatives and controls in making more errors on the antisaccade task and having longer response times on the Stroop task, especially the incongruent condition. Patients also had general, that is, condition independent, increases in reaction times on the go/no‐go and flanker tasks and made more errors on the flanker and Simon tasks, suggesting general performance impairments independent of inhibitory demand. Relatives were characterized by hypometric antisaccade amplitude gain despite normal prosaccades, suggesting a selective deficit in non‐standard sensorimotor transformations. Schizotypy was correlated with inhibitory performance across a number of tasks in both relatives and controls. Generally, these effects were independent of verbal intelligence levels. Overall, the findings point to rather selective impairments of inhibitory control in the schizophrenia spectrum and confirm a previously observed deficit in antisaccade spatial accuracy as an endophenotype of schizophrenia.     

Diagnostic differences in social anhedonia: a longitudinal study of schizophrenia and major depressive disorder

This study examined the hypothesis that, in schizophrenia, elevated trait social anhedonia (SA) is a stable individual difference, whereas in depression, increased SA is a reflection of a current clinical state that will diminish with recovery. Differences in trait Negative Affect (NA) and Positive Affect (PA) were also examined. Individuals with schizophrenia (n = 55) and depression (n = 34) were evaluated at baseline during hospitalization and compared with nonpsychiatric control participants (n = 41). Participants were assessed again at a 1-year follow-up. At baseline, compared with control participants, individuals with schizophrenia and depression were both characterized by elevated SA, greater NA, and lower PA. In schizophrenic individuals, elevated SA remained stable over the follow-up. However, in recovered depressed patients, SA declined over the follow-up period. Group differences remained in NA and PA over the 1-year follow-up. These results support the view that elevated SA is enduring in schizophrenia but that elevated SA is transiently related to clinical status in depression.     

The latent structure and coincidence of hypohedonia and schizotypy and their validity as indices of psychometric risk for schizophrenia

Recent exchanges on the place of hypohedonia within Meehl's theory of schizotaxia, schizotypy, and schizophrenia focus on evidence of the taxonicity of asociality, not hedonic capacity per se. Two hypotheses were contrasted, one that hypohedonia is a nonpathological individual difference variable independent of schizotypy, the other that schizotypy and hypohedonia tap independent taxonic processes that predict the emergence of positive and negative signs of schizophrenia, respectively. Undergraduates (n = 1,543) completed a multifaceted measure of schizotypy and hypohedonia. A consecutive subsample of these (n = 284) also completed a continuous performance test and the Symptom Checklist 90-Revised. Independent taxometric analyses (maximum covariance and maximum eigenvalue) indicated schizotypy was taxonic and hypohedonia was dimensional. Their coincidence was no greater than chance. Schizotypy was associated with impaired attention and significant psychological distress, whereas hypohedonia was not. Hypohedonia does not behave like a core component of schizotypy.     

Jumping to Conclusions bias,BADE and Feedback Sensitivity in schizophrenia and schizotypy

Several studies about schizophrenia have shown a cognitive bias named “Jumping to Conclusions” (JTC), defined as a decision made quickly on the basis of little evidence that occurs in these patients when performing probabilistic reasoning paradigms. The main objective of this study is to compare JTC bias and BADE (Bias Against Disconfirmatory Evidence) in patients with schizophrenia vs. participants with high/low schizotypy to understand the underlying mechanism of these cognitive biases. Probabilistic reasoning was assessed using a modified version of Drawing to Decision task. In addition to the traditional parameters of this task (Plausibility Rating (PR), Draws to Decision (DTD), BADE) we also calculated new parameters, overall accuracy and one named Feedback Sensitivity (FS) which lower scores shows greater use of feedback. The results of the study suggest a context effect: in the cued condition, there were not main differences between groups. In the uncued condition, we found higher JTC bias at stage 1 for patients. At the same time, PR at first stages related positively with Feedback Sensitivity and negatively with accuracy for patients and high schizotypy participants (high confidence is associated with worse performance and lower feedback use). BADE seems unrelated to JTC bias and FS. The results are discussed in terms of JTC like as a clinical bias and whether patients with schizophrenia are less able to use feedback.     

Schizotaxia, schizotypy, and schizophrenia: Paul E. Meehl's blueprint for the experimental psychopathology and genetics of schizophrenia

Paul E. Meehl proposed a model of the cause and pathogenesis of schizophrenia and related states in the early 1960s (Meehl, 1962), which he later revised in 1990 (Meehl, 1990). His model emphasized a genetically influenced aberration in neural transmission that could eventuate in clinical schizophrenia, nonpsychotic schizotypic states, or apparent normalcy depending on the coexistence of other factors. His model embodied the core ideas of the diathesis-stressor framework that would come to dominate experimental and developmental psychopathology for the next 40 years. The author reviews Meehl's model of schizotaxia, schizotypy, and schizophrenia and reviews and clarifies some frequent misunderstandings of the model.     

On being imitated: Effects on reward and reward value of the imitator

The effects of being imitated on the model's reward of imitating and nonimitating confederates and on the confederates' reward value were assessed. Forty-eight first graders served as subjects. It was found that more children showed a bias in giving reward to the imitating confederate than to the nonimitating confederate. This effect was particularly strong for children classified as having an internal locus of control. Second, no difference in confederates' reward value was obtained as measured by operantly conditioned responding on a marble-drop task.     

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.     

The "minimal self" in psychopathology: re-examining the self-disorders in the schizophrenia spectrum

The notion of minimal, basic, pre-reflective or core self is currently debated in the philosophy of mind, cognitive sciences and developmental psychology. However, it is not clear which experiential features such a self is believed to possess. Studying the schizophrenic experience may help exploring the following aspects of the minimal self: the notion of perspective and first person perspective, the 'mineness' of the phenomenal field, the questions of transparency, embodiment of point of view, and the issues of agency and ownership, considered as different and less fundamental than the feeling of mineness. Two clinical vignettes of patients with the diagnosis of schizophrenia will be presented: the first one, illustrating early illness stages, and the second case, of chronic schizophrenia, symptomatically marked by persistent hallucinations. Through their analysis, we will discuss the experiential dimensions of minimal self.     

奖赏和损失情境下男性海洛因戒断者的风险决策缺陷

摘 要 采用修改版的多伦多赌博任务考察决策情境对海洛因戒断者风险决策的影响。研究结果主要发现,海洛因戒断者在损失情境下的风险寻求决策比率与吸毒年限显著正相关,这种相关提示了风险决策背景下海洛因成瘾者持续使用毒品与其较低的损失敏感性之间的复杂交互作用。其次,海洛因戒断者在做出风险决策后收到消极反馈时的风险规避倾向可以负向预测其风险寻求决策比率,这可能进一步反映了海洛因戒断者风险感知的钝化或其对消极反馈信息的整合加工存在异常。     

Effects of reward and familiarity of reward agent on spontaneous play in preschoolers: a field study

A field experiment was conducted with preschool children to test the effect of rewards on a familiar, spontaneous play activity, in conditions as close as possible to the children's natural school context, and to examine the role of familiarity of the person who administered rewards. In three experimental conditions, children were rewarded either by their own teacher or by an unknown adult for playing with toys at the school playground and stayed with either the teacher or the unknown adult in the remaining part of reward sessions. Spontaneous play was significantly reduced by the reward relative to baseline levels and recovered after a 3-wk. interval. However, no difference due to familiarity/unfamiliarity of reward agent could be found. Results, discussed in terms of an incentive contrast hypothesis, attest to the generality and external validity of the undermining effects of rewards.