Critical interstimulus interval in delusional schizophrenics and normals.

The critical interstimulus interval, the minimum interval between presentation of a test and mask stimulus at which the mask no longer interferes with processing of the test stimulus, was calculated for 10 schizophrenics with delusional symptoms and 10 normal college students. All Ss had previous experience with the masking procedure. Each S's critical interstimulus interval was obtained 4 times in 4 separate sessions. Results indicate a larger critical interstimulus inteval for the schizophrenics. All Ss also showed less masking with practice. Results are consistent with A. J. Yates's (see record 1966-05514-001) hypothesis of a schizophrenic deficit prior to cortical levels of information processing but were inconsistent with A. J. Yates and P. Korboot's (see record 1971-06730-001) findings that slow information processing is unique to chronic nonparanoid schizophrenics. Post hoc analysis suggests the possibility of an additional schizophrenic deficit in preattentive filtering. Directions for future research are discussed. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Number and position of visual stimuli as determinants of reaction time in schizophrenia.

Notes that RT in normal Ss has been shown to be linearly related to stimulus complexity, defined as the log of the number of equally probable stimuli to which a response may be made. Data from an earlier study of 40 short- and long-term paranoid and nonparanoid male schizophrenics and 10 male hospital employees were reanalyzed and compared with P. Venable's (see record 1959-10789-001) study of schizophrenic deficit. Although experimental procedures were dissimilar, both studies found that increased complexity did not result in schizophrenics having steeper regression slopes than normal Ss. Consideration of the position of the critical stimulus, however, clearly indicated that long-term, nonparanoid schizophrenics narrow attention to central cues when confronted by an increase in complexity. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sentence processing in schizophrenic listeners.

40 hospitalized schizophrenics and 40 volunteers from the community (age range for both groups 17-59 yrs) listened to sentences in which a click was embedded. 20 schizophrenic Ss and 20 normal Ss were asked to reproduce the sentences and indicate precisely where the click occurred. The remaining Ss were given the previously heard sentences and asked to recognize the click locations. Results show that schizophrenic Ss tend to be less accurate than normal Ss in locating the clicks. However, this inferior performance was not due to an inability to use syntactic rules. Rather, the pattern of errors demonstrated that schizophrenic Ss distinguish between sentences which are acoustically identical but syntactically distinct, and that this distinction is maintained under response conditions with varying emphases on sentence retrieval. It is concluded that schizophrenics appear to use syntax as a basis for sentence processing at least to the same extent as normal Ss do. (27 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory processing speed and signal detection in schizophrenia.

Examined 2 differing explanations of schizophrenic processing deficit, J. Chapman and A. McGhie's (1962) and A. J. Yates's (see PA, Vol 41:10769). 32 18-46 yr old schizophrenics, classified on the acute-chronic and paranoid-nonparanoid dimensions, and 8 17-45 yr old neurotics were tested on 2 dichotic listening tasks. One task gave reaction time measures of processing speed at 3 rates of stimulus presentation; the other assessed stimulus detection and channel selectivity using theory of signal detection methods. Results support Yates and indicate that schizophrenics can attend successfully to 1 of 2 competing channels. Neither reduced sensory sensitivity nor response bias appeared to affect the performance of any group of Ss. Slowness of processing was a deficit characteristic of chronic, particularly nonparanoid, schizophrenics, although the factors responsible for this slowness remain a matter for empirical investigation. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Schizophrenic memory-search performance involving nonverbal stimulus properties.

Investigated schizophrenic memory-search performance by conducting a memory-search choice-reaction-time (CRT) task involving nonverbal stimulus properties (real-life sizes of items). Procedures were designed to diminish ambiguities concerning previous evidence of possible schizophrenic impairment in scanning and comparison operations involving memory-held items. Ss (aged 18–60 yrs) were 20 paranoid and 20 nonparanoid schizophrenics, 20 psychiatric controls, and 20 normal Ss. Results indicate that scanning and comparison operations proceeded at comparable rates among the schizophrenics and controls. On the other hand, rates of encoding the presented stimulation for a given trial (the trial's probe item) into a task-facilitative format proceeded at a slower rate among the paranoid Ss in particular. Discussion focuses on specific memory-search CRT paradigmatic conditions in which intact speed of memorial item comparisons tended to be most evident among these patients. Results resemble earlier observations of the present 2nd author (see record 1978-31872-001) on memory-search CRT performance among paranoid and nonparanoid schizophrenics when probe stimulation has remained in view throughout each trial. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Abstract thinking and social behavior in schizophrenia.

20 normal and 24 schizophrenic Ss were presented a series of cards, each bearing a stimulus word and 2 response words variously related in meaning to the stimulus. The Ss were asked to select the response word which they felt to be "closer in meaning" to the stimulus word. The results confirmed, at the .01 level, the hypotheses that (a) normals will exceed schizophrenics in the ability to select, as most similar in meaning to a given word, that word which is related to it in an essential abstract way; and (b) within a schizophrenic group, the above ability will be positively correlated with adequacy of everyday social interaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Concept identification by schizophrenic and normal subjects as a function of problem complexity and relevance of social cues.

Schizophrenic and normal Ss (N = 230) solved concept-identification (CI) problems varying in stimulus complexity, simultaneously with either a normal or a schizophrenic stooge providing relevant or irrelevant cues. Major results were (1) CI performance was a negative function of stimulus complexity, (2) social cues from a normal stooge had greater effects on problem solving than social cues from a schizophrenic stooge, and (3) schizophrenics demonstrated a deficit in problem solving connected primarily with the use of social cues. Comparisons of these data with expectations based on a mathematical model of CI revealed several significant discrepancies, attributable primarily to the fact that normals are more sensitive to social cues than are schizophrenics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Schizophrenic short-term memory: A deficit in subjective organization.

24 schizophrenic and 24 normal Ss received 3 trials on each of 2 lists of trigrams, 1 being for recognition and the other for recall. 1/2 of the Ss received special instructions for alphabetical ordering of the recall terms, while the other 1/2 was asked to do their best. Special instructions facilitated recall of normal Ss, but not of schizophrenics. Instructions had no significant effect upon the recognition scores. The effect of trials was to increase schizophrenic recall, but not recognition, while normals showed gains both in recall and recognition. It is concluded that the schizophrenic recall deficit results, in part, from an inability to subjectively organize memory store. (French summary) (28 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Creativity and schizophrenia: An equivalence of cognitive processing.

Two tests of creativity were given to 10 paranoid and 10 nonparanoid schizophrenics, 10 nonpsychotic psychiatric controls, and 10 normal Ss. Ss were aged between 18 and 50 yrs. Scores on vocabulary and similarities tests, as well as education, medication, marital status, socioeconomic background, and age, were examined. Results indicate that nonparanoid schizophrenics were significantly more creative than paranoids and psychiatric controls on one creativity measure, a graded level measure of the Alternate Uses Test. Also, nonparanoid schizophrenics produced a significantly higher percentage of "highly creative" responses than did normals. Nonparanoid schizophrenics also scored higher than the other groups on the Welsh Figure Preference Test, but this finding was found to be related to age rather than to schizophrenia. The superior performance of the nonparanoid schizophrenic is discussed in terms of the encouragement that a supportive, nonjudgmental testing environment provides. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A prediction of patterns of schizophrenic error resulting from semantic generalization.

Conducted a study with 2 groups of 26 male schizophrenics and normal psychiatric aides (mean age = 45 yr) to test predictions derived from a theory of disordered thought by L. J. Chapman, J. P. Chapman, and G. A. Miller (see PA, Vol. 39:10059) concerning the conditions under which schizophrenic Ss exhibit excessive generalization errors. The theory assumes that both the schizophrenic and normal are biased toward responding to words in terms of the words' strongest aspects of meaning, but that schizophrenics are more strongly biased toward this than are normals. Ss were instructed to indicate by pressing buttons marked "yes" and "no" whether or not test words presented in serial fashion on a memory drum had appeared on a previous training list. "Yes" responses to test words not appearing on a previous training list were the measures of generalization errors. The predictions were supported by the finding that schizophrenics made significantly more errors to words on the test list that shared strong meaning responses (p     

Are schizophrenics' behaviors schizophrenic? What medically versus psychosocially oriented therapists attribute to schizophrenic persons.

Tested the hypothesis that the medical and psychosocial therapeutic models are differentially reflected in therapists' perception of and attributions to schizophrenics. 36 20–58 yr old hospital staff (medically oriented) and 23 23–52 yr old alternative-care staff (psychosocially oriented) participated in 2 structured interviews; orientations were ascertained by the Client Attitude Questionnaire. Ss were given 4 hypothetical case studies, 2 of schizophrenic individuals and 2 of normal individuals. Ss rated case study personalities and explained their normal behaviors, such as selling T-shirts or singing in the shower. Relative to the alternative-care staff, the hospital staff attributed less freedom of choice and less purposefulness to the behaviors of the schizophrenics. They were also more likely to explain schizophrenic target persons' behaviors in terms of an underlying illness, rather than as a response to situational factors. No differences between groups were found in the amount of similarity perceived between self and the schizophrenic cases or in the degree of global freedom of choice attributed to the schizophrenic cases. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparisons of the restricted association of chronic schizophrenic and normal control subjects.

Obtained 11 types of restricted associations and free associations from 24 chronic schizophrenics and 24 normal controls equated for age and education. The associations of schizophrenics were more variable than those of normal Ss, especially on tasks which most restricted the choice of responses. Agreement in responding between normal and schizophrenic Ss was markedly lower when compared with that between high- and low-creative Ss, or with 1-yr, test-retest data. Repetition of responses given to the same stimuli under different instructions was markedly higher for schizophrenic than normal Ss, and thus the degree of task and response differentiation was reduced. The restricted associations overlapped with free associations more markedly for schizophrenic than for normal Ss, but the general structure of a conceptual semantic space was about the same for both groups. It is argued that when explicit constraint in tasks of verbal associations is high, schizophrenic Ss, more than normals, impose a low degree of implicit constraint on their verbal behavior; when the external constraint is low, they increase their implicit constraint. (26 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual information-processing deficits in chronic schizophrenic subjects using tasks matched for discriminating power.

Compared the performance of 24 18–52 yr old hospitalized schizophrenics with that of 18–48 yr old normal controls on 3 matched visual information-processing tasks. Each of the 3 tasks involved deciding on the relative magnitude of 2 groups of letters. The 2 experimental conditions, one in which irrelevant distracting stimuli were added and the other in which response demands were increased, were matched for discriminating power with a neutral condition. Results show a significant reaction-time difference between groups on all 3 tasks, implying an overall reduction in processing speed among schizophrenics. However, schizophrenic Ss were not specifically sensitive to the effects of visual distraction or increased response complexity. Data are consistent with theories of schizophrenic deficit that emphasize the generalized nature of the cognitive disturbance and relate the level of deficit on particular tasks to the amount of capacity required to complete processing. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotional experience and expression in schizophrenia and depression.

Examined the emotional responses of schizophrenic, depressed, and normal Ss and whether differences in the emotional responding of these groups depended on how emotional responses were elicited or measured. 23 blunted and 20 nonblunted schizophrenics, 17 unipolar depressed Ss, and 20 normal Ss were exposed to a series of affect-eliciting stimuli. The stimuli varied in valence (positive vs negative) and in level of cognitive demand. Ss reported their subjective experiences, and their facial expressions were videotaped. Blunted schizophrenics were the least facially expressive, although their reported subjective experiences did not differ from those of the other groups. The nonblunted schizophrenics were more responsive than the depressed Ss to the positive stimuli, although the 2 groups did not differ in their clinical ratings of affective flatness. (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)     

Perceptual closure in schizophrenia.

The concept of closure has been more frequently investigated using normal Ss than psychotic patients. The present study utilizes schizophrenics and compares their performance with a comparable group of hospitalized nonpsychotic Ss. Taylor's (1960) test of closure was used. Tendency to closure tended to be lower for the schizophrenics than for the nonschizophrenics, with schizophrenics on drugs (and, hence, manifesting a greater degree of personality disorganization than the other schizophrenic Ss) showing no tendency towards closure. The results are related to 2 theories of schizophrenia, one which involves a deficit in the energizing or arousal systems in the brain, and the other, an inability to maintain a set in the way normal Ss do. From Psyc Abstracts 36:04:4JQ31S. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sentence perception and distractibility in schizophrenic, manic, and depressed patients.

Previous research with schizophrenics suggested that distraction may have its primary effect on controlled information processing. To explore this hypothesis, 8 schizophrenics, 8 manics, 8 depressives, and 8 normal Ss (all Ss were aged 18–45 yrs) were asked to shadow short stories in both the presence and absence of a competing message and to answer questions afterward about the content of the shadowed message. The shadowing performance of all 3 patient groups was equivalent to that of normal Ss and was not affected by distraction. Shadowing errors of commission indicated that schizophrenics did use semantic and syntactic information to anticipate words in the relevant message, but the schizophrenics also inserted more semantically irrelevant words than any of the other 3 groups. Distraction did interfere with the schizophrenics' ability to recall the content of relevant passages, but not with the performance of the other 3 groups. Data indicate that distraction may have a specific rather than general influence on controlled information processing or that distraction may reduce schizophrenics' overall capacity to handle information in short-term memory. The analysis of shadowing errors suggested that performance on such laboratory tasks may be closely related to the verbal communication problems encountered by many schizophrenic patients, but also that these symptoms may not be a simple function of selective attention difficulties. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reversal and extradimensional shifts in abstract and concrete schizophrenics.

72 concrete schizophrenics, defined in terms of conceptual sorting difficulties, were trained under 1 of 3 discrimination-learning conditions: reversal (R) shift, extradimensional (ED) shift, or control. 72 abstract schizophrenics were similarly divided, 1/2 of the Ss in each condition received verbal reinforcement, and 1/2 received candy reinforcement. Results indicated that concrete Ss required significantly more trials to learn the shift concepts than abstract Ss. Both R and ED shifts produced negative transfer relative to control conditions, but there was no significant difference between the 2 shift conditions. No differential effect was attributable to the different reinforcers. Results were discussed in terms of 2-stage discrimination-learning models and Goldstein's theory of schizophrenic concreteness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)