WAIS Performance IQ Research Articles

Variations of the 2-line inspection time stimulus

Mackenzie and Bingham [(1985) Australian Journal of Psychology, 37, 257–268] used a variation of the 2-line Inspection Time (IT) task shifting the stimulus position between trials to prevent focussing of attention and obtained 71% thresholds which correlated -0.50 with WAIS Performance IQ. Nettelbeck [(1987) Speed of information-processing and intelligence. Norwood, NJ: Ablex] estimated the mean 97.5% threshold for Mackenzie and Bingham's subjects was 262 msec where other Inspection Time studies obtain estimated 97.5% thresholds of around 100 msec, and suggested the higher mean threshold estimate might be due to the changes in stimulus position. This experiment investigates whether the higher thresholds obtained by Mackenzie and his associates are due to the changes in stimuli used. Fifty non-retarded adults served as subjects for: M, stimuli which changed position as in Mackenzie and Bingham (1985); S, stimuli similar to M presented in fixed position; and N, stimuli more similar to the conventional 2-line stimuli in contrast and mask width. There were no significant differences between the 3 stimuli in their mean thresholds or in their correlations with progressive matrices (mean r = -0.61). The mean 79% threshold of 90 msec converts to an estimated 97.5% threshold of 216 msec. It follows that changing stimulus position (M vs S) or stimulus contrast or mask width (S vs N) are not responsible for the higher estimated 97.5% thresholds. The present study has obtained for the whole sample a correlation between mean IT and intelligence, -0.61, which is significantly higher than Hunt's [(1980) British Journal of Psychology, 71, 449–474] 0.3 barrier. Correcting possible skew in IT by log transform produces a correlation of -0.64, and there is no evidence that the correlation is substantially lower for subjects of above average IQ, after correcting for restriction of range r = -0.55.

MMPI correlates of performance intellectual deficits in patients with right hemisphere lesions.

This study investigated the emotional adjustment of 50 patients with focal brain damage in the right hemisphere (RHD). The impact of functional loss (as assessed by the WAIS Performance IQ) was assessed by a multivariate comparison of the composite MMPI profiles of these patients as classified into three groups: Below Average, Average, and Above Average Performance IQ. Regardless of the extent of decline in Performance-related abilities, right hemisphere impairment was associated with symptoms of mild depression, loss of initiative, anxiety, denial, and somatic preoccupations. MMPI scores were not correlated significantly with their WAIS Performance IQs. Implications for neuropsychological assessment are discussed.

Figure-object matching: Another frequent nonverbal impairement of aphasics

389 focal brain-damaged patients were examined by means of a nonverbal Figure-Object Matching Test (FOMT) and standardized aphasia battery. An LH lesion proved to be more relevant than an RH lesion to the outcome on FOMT. Both the presence and severity of aphasia play a significant role in the poor outcome on FOMT while type of aphasia, intelligence impairment (WAIS performance IQ) and presence of a visual field defect do not. It is concluded that this type of nonverbal defect of aphasics reflects a basic disorder, linked in some way to language impairment.

Wais Performance IQ in Aphasia as a Function of Auditory Comprehension and Constructional Apraxia

This study investigated differences in nonverbal intelligence between diagnostic subgroups of aphasics using the Performance Tests of the Wechsler Adult Intelligence Scale (WAIS). Subjects were 98 right-handed hospitalized males with unilateral left-hemisphere damage who had unambiguous clinical diagnoses of Broca's, Anomic, Conduction, Mixed Non-Fluent, Wernicke's, or Global aphasia. Group differences were examined using the WAIS Performance IQ (PIQ), subscores for spatial organization (Block Design and Object Assembly) and for verbalizability (Picture Completion and Picture Arrangement).There were significant group differences for each WAIS score, determined by the impaired performance of the Global aphasics. With covariance correction for level of auditory comprehension, group differences were eliminated on the verbalizable subtests, but not on the spatial organization subtests. Covarying for level of constructional apraxia (assessed with drawings, sticks, blocks), however, eliminated group differences for both subscores. Using demographic, neurological, linguistic variables, multiple regression analyses confirmed the covariate analysis findings; constructional apraxia was the most predictive variable for both spatial and verbalizability subscores, while auditory comprehension and education level predicted performance on the verbalizable subtests.

Focal changes in cerebral blood flow produced by a test of right-left discrimination

A sensorimotor control activation task was used to isolate the focal cerebral blood flow changes resulting from the visual and cognitive processing of a right-left discrimination task. Eleven normal right-handed males participated. The sensorimotor control task produced significant bilateral increases in flow in most cortical channels. Significant bilateral parieto-occipital activation was found for the right-left discrimination task over and above the flow changes produced by the sensorimotor control task. The left occipital flow increase resulting from the right-left discrimination task was found to be negatively related to task performance. An inverse relationship was also found between WAIS Performance IQ and the blood flow change in the left parietal channel. These results suggest areas for further testing concerning potential individual differences in cognitive processing during the performance of a right-left discrimination task.

Some Information-Processing Correlates Of Measures Of Intelligence.

Measures of verbal and non-verbal intelligence, both group and individually administered, were related to a set of laboratory-based measures of human information processing. Speeded non-verbal intelligence (WAIS Performance IQ) and verbal comprehension (group administered vocabulary tests) were most highly predictable. While high performance IQ was associated with greater right hemisphere efficiency in processing non-linguistic stimuli, those high on the verbal comprehension measures were better able to overcome linguistic conventions under experimental manipulation.

Relationship between Quick Test and Wais IQS for Brain-Injured and Schizophrenic Subjects

Quick Test IQs (combination form) correlated highly with WAIS Full Scale IQs (.80, .79) and WAIS Verbal IQs (.86, .79) obtained from separate groups of 48 brain-injured and 48 schizophrenic Ss. Significantly lower relationships were found between Quick Test IQs and WAIS Performance IQs (.60, .56). These results were interpreted as supporting the position that the Quick Test is a valid, reliable estimate of intelligence which “holds up” with populations notorious for their variability and which seems resistant to the type of reduction in performance on intelligence test tasks often associated with psychopathology.

Relationship between the Qt and the Wais

Quick Test IQs (combination form) correlated highly with WAIS Full Scale IQ for 43 neuropsychiatric inpatients. A significantly higher relationship was found between WAIS Verbal IQ and QT scores than between WAIS Performance IQ and QT scores. The results were interpreted as supporting the position that the QT is a good estimate of intelligence which is highly resistant to the reduction in performance on some intelligence test tasks often associated with psychopathology.