Size estimation in schizophrenic and nonschizophrenic subjects.

Studied size estimation in 120 male acute and chronic schizophrenic and nonschizophrenic psychiatric patients. No significant group differences were found in the size estimation levels, or when the groups were subdivided on the basis of both premorbid adjustment and paranoid status. All Ss increased their size estimation levels over the 3 trial blocks. The thematic content of the stimuli produced a significant effect in the chronic schizophrenic group, with the nonthreatening scenes being overestimated relative to the threatening scenes. Some methodological problems common to size estimation studies are noted, and the growing inconsistency in the size estimation literature is hypothesized to be due to these problems. (23 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social competence and posthospital outcome among schizophrenic and nonschizophrenic psychiatric patients.

Although E. Zigler and L. Phillips (see 37:1 and 38:6) contend that an identical relationship between premorbid social competence and prognosis is found in both a schizophrenic and nonschizophrenic hospital population, supporting data are not presented. To test this hypothesis, the 3-yr posthospital outcomes of 81 schizophrenic and 85 nonschizophrenic previously hospitalized patients were separately related to the Zigler and Phillips' Social Competence Scale. The results indicate that among schizophrenics social competence is positively related to 2 out of 5 indexes of posthospital outcome: incidence (p     

Production of associative sequences in process-reactive schizophrenic and nonschizophrenic groups.

A previous study (Judson & Katahn, 1960) disclosed significant differences between process-reactive schizophrenics in the recall of friends' names over a 10-minute interval. The differences were greater than would have been expected from their recall of animal names and IQ scores. This was interpreted as reflecting a special restriction in interpersonal relationships in a generally impoverished relationship with the environment. The present study sought to extend the findings and employed both schizophrenic and nonschizophrenic patients. Both the process-reactive dimension and diagnostic category made significant independent and interacting contributions to the recall of friends' names, that is, the material with social connotations, but not to the recall of animal names. By subgroups, the rank order of recall from least to greatest, was process schizophrenics, process nonschizophrenics, reactive schizophrenics, reactive nonschizophrenics. The process-reactive distinction thus proved meaningful for nonschizophrenic as well as schizophrenic patients on this material. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Varieties of "disordered" thinking on the Rorschach: Findings in schizophrenic and nonschizophrenic patients.

Assessed 71 schizophrenic and nonschizophrenic hospitalized patients on 3 scales for aspects indicative of a thinking disorder on the Rorschach: disruption of logical thought, irrelevant or personalized associations, and elaboration in affective terms. Each scale could be reliably scored according to the criteria described. The scales correlated significantly with other Rorschach scores suggestive of thought disorder. All 3 scales were significantly higher in schizophrenic Ss than in depressed Ss (p     

Ethnocentrism and stimulus generalization.

"This study is an attempt to demonstrate that ethnocentrism is related to an 'over-generalization process' as has been postulated by various authors. The performance of a group of student nurses on a stimulus-generalization task was correlated with their scores on the California E scale yielding a significant μ = .44. Some possible theoretical implications are discussed and mention is made of further research which is in progress." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age and the discriminative "power" of the MMPI with schizophrenic and nonschizophrenic patients.

Compared the responses of 4 groups of 20 patients on 12 scales of the MMPI according to age (18-28 yr. or 45-56 yr.) and diagnosis (schizophrenic or nonschizophrenic). Results indicate that although young schizophrenics and nonschizophrenics were distinguished on the basis of expected profile differences, no significant differences were found between the 2 older groups. It is suggested that the greater communality of experiences shared by older Ss tends to have a leveling effect on overall profile differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of stimulus similarity in discrimination training upon wavelength generalization in pigeons.

Administered variable-interval training to 30 naive adult pigeons to peck a 550-nm light and then tested them for wavelength generalization. Ss were later assigned to 1 of 3 groups, matched for both relative generalization slope and response rate. One group then received successive discrimination training between the 555-nm stimulus (S+) and a vertical white line on a 555-nm background (S-); another group experienced the same S+ but a vertical white line on a black background as S-. A 3rd group received a comparable amount of single stimulus training with the 555-nm value. On a 2nd wavelength generalization test, the 1st group yielded greater sharpening of generalization than the 2nd group, whereas the 3rd group showed no change from Test 1. Results indicate that the sharpening of generalization gradients by discrimination training was directly related to the similarity of the discrimination training stimuli. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contextual modulation of stimulus generalization in rats.

One connectionist analysis of the acquired equivalence/distinctiveness of cues assumes that when similar compounds (e.g., AX and BX) are paired with the same outcome (e.g., food, +; or no food, ?), their components come to activate the same configural unit (ABX). When these compounds are paired with different outcomes, their components will come to address different units. Here, rats received appetitive training with eight compounds (e.g., AX+, BX+, CX?, DX?, AY+, BY?, CY?, DY+) that should generate the following configural units: ABX, CDX, ADY, and BCY. In Experiment 1, rats then received aversive conditioning to A, which should activate and revalue representations ABX and ADY. Subsequently, compounds that provided dual activation (i.e., BX and DY) of one of the revalued configural units (ABX and ADY) were shown to elicit greater fear than those compounds that provided a single source of activation to each unit (i.e., DX and BY). Experiment 2 confirmed and extended these findings. These results provide support for the connectionist analysis outlined above and are consistent with the application of this approach to the acquired equivalence/distinctiveness of cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Constant irrelevant cues and stimulus generalization in monkeys.

Trained 14 jungle-born female pigtailed monkeys to criterion on 2 concurrently presented 4-choice object discriminations. In 1 problem form was relevant and color constant irrelevant; in the other, color was relevant and form constant irrelevant. Following training, Ss were given transfer tests with a 4-choice setting consisting of the 2 formerly rewarded objects, a 3rd object composed of the rewarded relevant features of the color and form discriminations, and a 4th object constructed from the 2 constant irrelevant color and form features. Ss consistently chose the previously rewarded objects during transfer, but of the new objects, almost always chose the object constructed of relevant features. A number of models for discrimination learning are considered in the light of these data. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus generalization and overinclusion in normal and schizophrenic subjects.

Compared 38 male and 12 female schizophrenics and a matched group of normals on a test of stimulus generalization, Epstein's Inclusion Test, and the Vocabulary subtest of the WAIS. Schizophrenics generalized significantly more than normal Ss (p     

Mediated stimulus generalization and words connoting mood.

90 words connoting mood were scaled for degree of elation or depression. 70 of the words were selected as the stimuli in a study of mediated stimulus generalization. For 2 groups of men and 2 groups of women the training stimuli were extremely elated words, and for 2 different groups of men and women, the training stimuli were extremely depressed words. In each of the 2 groups for both sexes, one group was reinforced for whispering and the other for shouting. After training all groups received a generalization series consisting of words varying in degree of elation or depression. Ss trained to shout elated and whisper depressed stimuli produced steeper mediated stimulus generalization gradients than Ss trained to whisper elated and shout depressed stimuli. The Shout-Depressed group produced partially inverted gradients. The results were consistent with an asymmetrical Matching Principle: with connotative stimuli there is a strong tendency to make an intense response to an intense stimulus and a moderate tendency to make a weak response to a weak stimulus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A model for adaptation-level effects on stimulus generalization.

Presents a quantitative model of adaptation-level (AL) effects on stimulus generalization and integrates results from single stimulus, go–no-go, and choice discrimination training paradigms. The model accurately predicts (1) the gradualness of the shift in responding during the course of asymmetrical generalization testing, (2) the relation between the degree of asymmetry and the amount of shift, (3) the effect of overrepresenting certain stimuli during testing, and (4) the effect of varying the amount of training. With the discrimination training paradigms, the effects of the degree of separation between the training stimuli and of the relative frequency of their presentation during training and subsequent generalization testing are consistent with an extension of the basic model. Finally, new research is described affirming the applicability of the AL model to several infrahuman species. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationship of manifest anxiety to stimulus generalization.

This study examined the relationship between anxiety and stimulus generalization in psychiatric patients. The results suggested that "there is no relationship between MAS [Manifest Anxiety Scale] and stimulus generalization in psychiatric Ss. Moreover, situational factors do not seem important in limiting the generality of such an interpretation. Since the relationships between anxiety and learning phenomena are generally well recognized, these negative results presumably reflect the inadequacy of the Taylor scale as a relevant index of anxiety levels in psychiatric subjects." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A model for stimulus generalization in Pavlovian conditioning.

Presents a review of experiments that demonstrate the effects of generalization decrement in Pavlovian conditioning and argues that an adequate theoretical explanation for them is currently not available. A theoretical account for the processes of generalization and generalization decrement in Pavlovian conditioning is developed. This model assumes that animals represent their environment by a stimulus array in a buffer and that this array in its entirety constitutes the conditioned stimulus/stimuli (CS). Generalization occurs when some stimuli represented in the array on a test trial are the same as some of those represented in the array during training; the magnitude of generalization is determined by the proportion of the array occupied by these common stimuli during training compared with the proportion of the array they occupy during testing. It is proposed that this model can explain all the results that were difficult for its predecessors to account for. (52 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integrality/separability of stimulus dimensions and multidimensional generalization in pigeons.

The authors present a quantitative framework for interpreting the results of multidimensional stimulus generalization experiments in animals using concepts derived from the geometrical approach to human cognition. The authors apply the model to the analysis of stimulus generalization data obtained from pigeons trained with different sets of stimuli varying along two orthogonal dimensions. Separable pigeons were trained with stimuli varying along the dimensions of circle size and line tilt, dimensions found to be separable in previous human research; integral pigeons were trained with stimuli varying along two dimensions of rotation in depth, dimensions that are intuitively integral and which hold special interest for theories of object recognition. The model accurately described the stimulus generalization data, with best fits to the City-Block metric for separable pigeons and to the euclidean metric for integral pigeons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Affective reactivity of speech in schizophrenia patients and their nonschizophrenic relatives.

This study compared levels of referential communication disturbance in speech samples from 41 stable schizophrenia outpatients, 46 parents of patients, and 23 nonpsychiatric control participants in affectively positive versus affectively negative conditions. The speech of the patients and parents showed elevated frequencies of reference failures in the affectively positive condition compared with control participants; the speech of the patients became more disordered in the affectively negative condition, whereas the speech of the parents did not. These results support the idea that referential communication disturbances reflect vulnerability, as well as overt illness, but that affective reactivity of these disturbances is associated mainly with the manifest illness. These findings are consistent with biological, cognitive, and psychological theories about the processes underlying stress responsiveness of schizophrenic symptoms more generally. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of social and nonsocial censure on stimulus generalization in neurotics and schizophrenics.

36 schizophrenic and 36 neurotic depressive Ss were given a visual-spatial generalization task under either social or nonsocial (impersonal) censure conditions. The following hypotheses derived from previous investigations were tested: (1) schizophrenics would show higher gradients of generalization than neurotic depressives, and (2) generalization gradients would be higher under conditions of social as opposed to nonsocial censure, especially in schizophrenics. The data supported Hypothesis 1 but not Hypothesis 2. There was no evidence for differential responding between these 2 groups with respect to either stimulus generalization or response to censure. It was suggested that hypotheses concerning the schizophrenic's performance in these 2 situations have been biased and oversimplified by use of normal, rather than patient, control groups in previous investigations. (22 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ethnocentrism and stimulus generalization: A replication and further study.

Data were previously reported giving "support to the hypothesis that ethnocentrism represents an 'overgeneralization phenomena.' " In a study of 60 female student nurses, aged 18 through 22, who were given the MMPI, the CVS Intelligence Scale, and the California Ethnocentrism Scale as well as two stimulus generalization (SG) tasks, significant correlations were not found between E Scale scores and total error scores on each stimulus generalization task. Previous positive finding "must therefore probably be attributed to chance. While present results do not preclude the possibility that ethnocentrism is related to overgeneralization in thinking, the functions involved in performance on the tasks investigated do not appear to be on the same psychological continuum." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task specificity in nonspecific transfer and in extradimensional stimulus generalization in pigeons.

Determined whether discrimination training per se is sufficient to produce positive nonspecific transfer and whether it sharpens extradimensional stimulus-generalization gradients, using domestic pigeons. In Exp I, 8 groups of Ss received true-discrimination (TD) or pseudodiscrimination training between 2 line orientations in either (a) a successive-conditional (SC) discrimination prior to transfer to a true SC or (b) a go/no go (GN) discrimination between 2 colors. Discriminative performance in transfer was facilitated only when the original and transfer discriminations were of the same type. Exp II showed that positive nonspecific transfer was primarily mediated by the transfer of task-specific learning rather than by the transfer of attentiveness. In Exp III, 4 groups were trained as in Stage 1 of Exps I and II and given single-stimulus training with a chromatic stimulus, followed by a wavelength stimulus generalization test. Only TD-GN discrimination training produced sharp gradients, an effect leading to the conclusion that GN discrimination training and stimulus generalization are closely related by task requirements rather than by attention. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Autonomic nervous system activity in autistic, schizophrenic, and normal men: Effects of stimulus significance.

Deficits in attention and cognition in autistic children have been attributed to problems in the early stages of stimulus processing and to autonomic dysregulation, but the evidence is conflicting. Our study addressed this problem by recording skin conductance, skin temperature, respiration rate, and heart rate (HR) during (a) a rest period, (b) a series of nonsignal tones, and (c) a simple warned reaction time (RT) task in autistic, schizophrenic, and normal men; we sought to remove extraneous sources of variance by testing only high-functioning autistic men (n?=?13); age?=?18–39). Control subjects were age-matched normal men (n?=?19) and schizophrenic men (n?=?13) not chronically hospitalized. Autistic men had higher respiration rates, lower skin temperature, and higher HR variability at rest than controls. They were not different on other arousal measures or generally in responding to nonsignal tones but had severely impaired tonic and phasic autonomic responses and motor responses in the RT task. Schizophrenic subjects were also impaired but significantly less so in some aspects of responding. The results do not suggest problems in stimulus processing, but there is evidence of autonomic dysregulation and a pronounced inability to mobilize processing resources appropriately, perhaps a common problem with schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)