Early information processing deficit in schizophrenia. New findings using schizophrenic subgroups and manic control subjects.

In recent years, the idea that schizophrenia involves a primary disturbance of the higher cognitive (ie, cortical) thinking processes has been challenged by investigators who have shown that there may be a primary disturbance in schizophrenia in the early stages of information processing that occurs during the first few hundred milliseconds after the stimulus reaches the sense organs. Among the hypothesized early information processing deficits are deficiencies in iconic storage (a brief peripheral memory store) and slowness of processing from iconic storage to a more permanent memory system. Three experiments were conducted using tachistoscopically presented stimuli in order to evaluate these two stages of information processing (iconic storage and speed of processing) in schizophrenic and control subjects. Results converged in supporting the hypothesis, that independent of iconic storage and sensory registration, slow information processing is a relatively stable deficit of schizophrenic patients with a poor prognosis. The schizophrenic patients with a good prognosis had a similar deficit, which was reversible. Results are discussed as they relate to the early information processing deficit theories of schizophrenia.

Information processing dysfunction in paranoid schizophrenia: a two-factor deficit.

The authors investigated information processing in schizophrenia by studying 30 paranoid schizophrenic patients and 30 depressed inpatients. The basic methodology relied on tachistoscopic presentation of stimuli. First, the critical stimulus duration needed for identification of a target stimulus was determined. Second, when the target stimulus was followed by a masking stimulus, a measure of speed of information processing was obtained. The schizophrenic patients were imparied on input factors and speed of processing. The authors think it is unlikely that the results were due to medication effect or to gross psychopathology. Their discussion centers on how this two-factor deficit in information processing may result in cognitive disruption and how this study relates to other investigations.

Effect of antipsychotic medication on speed of information processing in schizophrenic patients.

The authors evaluated the effects of antipsychotic medication and schizophrenia on speed of information processing. Medicated (N - 20) as well as unmedicated (N = 16) schizophrenic patients showed more evidence of slow information processing than did depressed control subjects (N = 20). The medicated schizophrenic patients had higher levels of general psychopathology but also showed superior information processing speed compared with the unmedicated schizophrenic patients. These data confirm that the schizophrenic patients are slow information processors and that antipsychotic medication probably does not cause, and may actually reverse, slowness of information processing in schizophrenic patients.

The time course of information-processing deficits in schizophrenia.

A visual backward masking task was used to specify the time course of the information-processing dysfunction in 19 schizophrenic patients and 15 matched control patients using novel interstimulus intervals. The authors found that the information-processing deficit in schizophrenic subjects occurred at interstimulus intervals of greater than 60 msec and less than 500 msec. These data are compared with the results of evoked-potential and other psychophysiological studies. The visual-processing impairment is specific and time-linked rather than a reflection of the effects of gross psychopathology or medication in schizophrenic individuals.

Impaired speed of visual information processing in marijuana intoxication.

The authors conducted a double-blind crossover study to investigate the effects of marijuana on visual information processing. The authors used a tachistoscopic paradigm, and the results show no marijuana effect on the critical stimulus duration, a measure of stimulus intake. The visual backward masking data are compatible with a marijuana-induced slowness of information processing from labile unconscious iconic memory to more permanent memory processes. These results are discussed in relation to reports of marijuana's effects on perception and early information processing.

Information-processing abnormalities: trait- and state-dependent components.

Schizophrenics were compared to schizoaffective, bipolar, and nonpsychotic depressed patients in a visual masking paradigm in which an informational target stimulus was followed at varying intervals by a noninformational masking stimulus. In limiting the availability of the sensory signal provided by the target stimulus, the mask was used to probe how information from the environment enters and is processed by the central nervous system. The use of the masking paradigm was originally based on the hypothesis that thought disorder is a result of a more primary dysfunction in the processes that precede and result in thought. Results confirmed previous findings of a performance deficit in the schizophrenics when compared to nonpsychotic controls. Schizoaffective and bipolar patients also showed evidence of impaired processing, however. Results were interpreted in terms of a trait/state formulation in which impaired information processing is seen as a fundamental trait of schizophrenia spectrum disorders and as a state that can covary with psychotic illness in general. A unifying concept centers on the effects of psychopathological conditions on an individual's processing resources that results in either underprovision or overprovision of information from sensory input to complex cognitive operations dependent on the cerebral cortex. Findings from a variety of paradigms are consistent with those of the masking paradigm in revealing that the processing deficits of schizophrenics are time dependent and occur in the 500 ms following stimulus input.

Negative and positive cognition in depressed and nondepressed chronic-pain patients.

Several studies have suggested that depressed pain patients evidence more cognitive distortion than nondepressed pain patients and healthy controls. Although these studies have generally supported notions relating cognitive distortion to depressive functioning, other aspects of dysfunctional cognition have not been assessed in the chronic-pain population. The present study examined negative and positive automatic thoughts and attributional style in depressed pain patients, nondepressed pain patients, and healthy controls. Depressed chronic-pain patients were found to exhibit significantly more negative automatic thoughts than nondepressed pain patients and healthy controls. Conversely, nondepressed chronic-pain patients reported significantly more positive automatic thoughts than did depressed patients and healthy controls. No significant differences were found for attributional style. These results suggest that different cognitive-behavioral interventions might be considered for depressed compared to nondepressed chronic-pain patients.

Motivation: cause or confound in information processing/intelligence correlations?

The goal of the present study was to determine whether correlations between information processing scores and intelligence can be explained in terms of between-subject motivational differences. One hundred and nine male and female volunteer college students were tested on a battery of microcomputerized cognitive tests. One hundred of these subjects returned for a second session in which they were randomly assigned to an incentive or no-incentive condition and then retested. The effort expended on the tests was measured via heart rate, skin conductance, and a self-report questionnaire. Criterion measures, including the Advanced Otis-Lennon Test of Mental Abilities and Advanced Raven Progressive Matrices were also taken. The findings revealed that incentives had relatively modest effects on performance. In no case, however, did incentives affect the overall IQ-performance correlation for the tests used in the battery. These results support the view that correlations between information processing scores and intelligence reflect common mental capacities, rather than some affective variable such as motivation.

Schizotaxia, information processing and the MMPI 2-7-8 code type.

The relationship between the 2-7-8 MMPI code type and schizotaxia was investigated. College students whose Minnesota Multiphasic Personality Inventory profiles revealed a 2-7-8 code were compared to an elevation-free group on a visual information-processing task. The 2-7-8 group exhibited a processing deficiency similar to that previously found for schizophrenics and in-patient schizotypal personalities, supporting the construct validity of the 2-7-8 code as a measure of schizotaxia.

Feelings of inexperienced therapists in psychotherapy: a factor analytic study.

The Therapy Session Report, a parallel-structured response questionnaire, was utilized to study the feelings of inexperienced therapists. 57 college student applicants at a university counseling center reported on their perceptions of their therapists' feelings immediately following an intake interview. The 19 therapists, clinical psychology graduate students in training, also reported what they felt during the intake session. Factor analysis of patients, perceptions of their therapists' feeling resulted in four factors, the first two accounting for 85% of the common variance. Factor analysis of therapists, perceptions of their own feelings resulted in nine factors. Results suggest that, while patients view their therapists in generally negative positive terms, inexperienced therapists experience considerable affective discomfort during their intake sessions.

Interhemispheric visual masking.

Backward masking functions were evaluated in a paradigm in which target and masking stimuli were presented to opposite cerebral hemispheres using separate peripheral pathways. Backward masking occurred dichoptically when the target and mask were projected to opposite hemispheres. These findings indicated that some effective masking mechanisms are mediated by interhemispheric interactions independent of retinal phenomena.

Backward contralateral masking by light and by random pattern.

Letter-stimuli as targets were presented to the right or left visual fields and followed either by a flash of light or by a flash of light plus a patterned mask. The patterned mask always appeared in the opposite visual field of the letter targets. Analysis showed that masking occurred for both types of masks but that subjects produced more errors at each of five intervals between onset of the target and onset of the mask for the flash of light plus a patterned mask in the opposite visual field than for the flash of light alone. A pattern mask, when presented to the opposite visual field of a target stimulus, interferes with target processing at short target-mask intervals. These findings suggest that central backward masking may involve target-mask interactions beyond the visual cortex (Area 17).

Visual masking with presentations in same and opposite visual fields: evidence for contralateral masking.

Three experiments were conducted in a preliminary attempt to study the effects of presentations of an informational target stimulus to the right or left visual fields when the target was either preceded or followed by a noninformational masking stimulus and when the mask was presented to the same or opposite visual field of the target. Results indicated that masking was more effective in the same than in the opposite visual field but that masking of the opposite visual field was feasible for both forward and backward masking. Laterality effects were also found for forward and backward masking, with a modest advantage of the right visual field (left hemisphere) in both cases. Limitations of the data and directions for future research were discussed.

Luminance level and onset sequence of a pre- and post-exposure adapting field affects recognition of masked and unmasked stimuli.

Three experiments were conducted to evaluate the effects of the luminance level of a pre-/post-exposure field and onset sequence of a post-exposure field on briefly exposed visual stimuli for 13 male and 13 female undergraduate college students. Results showed that identification of a briefly exposed informational test stimulus as well as masking effects (the minimum interval between an informational test stimulus and non-informational backward visual noise mask) were both influenced by the luminance of the pre-exposure field and onset sequence of the post-exposure field.

Facilitation skills and the perception of clients' wants.

High functioning and low functioning observers as measured by the Carkhuff global level of facilitation scale were compared on their ability to perceive client wants. Observers were 16 master's level psychologists who had previously received 40 hours of Carkhuffian human relations training. After each counseling session the client and observer filled out the Therapy Session Reports describing what the client talked about (dialogue) and what the client wanted (wants). An agreement score between observer and clients was calculated for each observer. It was found that all observers were better able to identify dialogue. High facilitators were better able to identify wants than low facilitators (experimental task), while there was no difference between the groups in ability to identify dialogue (control task).