Jean P. Chapman

The measurement of handedness

A handedness scale consisting of 13 questionnaire items selected from those of D. Raczkowski, J. W. Kalat, and R. Nebes (1974, Neuropsychologia, 12, 43-47) was found to have high internal consistency for both males and females (coefficient alpha = .96 for both sexes), high test-retest reliability (r = .97 for males and .96 for females), and a correlation of .83 with a behavioral measure of handedness. Males exhibited more nonfamilial, but not familial, left-handedness than did females. Self-description as strongly right-handed or as strongly left-handed predicted questionnaire handedness categorization better than did hand used for writing.

THE MEASUREMENT OF DIFFERENTIAL DEFICIT

DISTURBED schizophrenics show a generalized performance deficit. They perform less well than normal subjects on almost any task that requires a voluntary response. Therefore, a lower than normal score on any single task cannot be interpreted as indicating a deficit of special importance in schizophrenia. Recognizing this, most investigators of cognitive deficit in schizophrenia have been concerned with differential deficit, that is, a greater deficit in one ability than in at least one other ability. Differential deficit in ability is measured using two or more tasks. A differential deficit in ability is inferred customarily from a greater performance deficit on one task than on at least one other task. On previous occasions we have pointed out that a differential deficit in performance does not necessarily indicate a differential deficit in ability. 1.2 It may, instead, merely reflect the schizophrenics’ generalized performance deficit coupled with the fact that one of the two tasks measures generalized deficit better than the other. We have pointed out that the higher are the reliability and the variance of a task, the greater will be the difference in mean score between the more competent and the less competent subjects. Since schizophrenics usually perform less well than normal subjects, they will show a greater performance deficit on the one of the two tasks that yields the greater dispersion of scores. We have advocated that to measure differential deficit in ability, one must match tasks on several psychometric characteristics. We explore this problem again now in order to offer what we believe to be a clearer statement of the problem. In addition, we now propose a solution with slightly less cumbersome requirements for adequately matched tests. (We use the term ‘tests’ here in the broad sense to include any task that is used to measure cognitive deficit). The central problem is how to move from statements about differential deficit in performance on specific tests to statements about differential deficit in ability. We will present here some implications of classic mental test theory for the solution of this problem. Some principles of psychometric theory When parallel tests are given on successive occasions, any given subject will usually not earn identical scores on the two testings. He will score differently even when he does not change in his knowledge of the material and shows no practice effects as a result of his taking the earlier tests. These fluctuations in test score are attributable to changes in such variables as the subject’s motivation, fatigue, emotional state, alertness, luck in guessing, and to *Preparation of this article was supported by a research grant (MH-18354) from the National Institute of Mental Health, United States Public Health Service.

A Longitudinal Study of High Scorers on the Hypomanic Personality Scale

Former college students (n = 36) identified by high scores on the Hypomanic Personality Scale (HYP; Eckblad & Chapman, 1986) were compared with control participants (n = 31) at a 13-year follow-up assessment. As hypothesized, the HYP group reported more bipolar disorders and major depressive episodes than the control group. The HYP group also exceeded the control group on the severity of psychotic-like experiences, symptoms of borderline personality disorder, and rates of substance use disorders. HYP group members with elevated scores on the Impulsive-Nonconformity Scale (Chapman et al., 1984) experienced greater rates of bipolar mood disorders, poorer overall adjustment, and higher rates of arrest than the remaining HYP or control participants.

The measurement of foot preference

Foot preference has been given only superficial attention in studies of hemispheric lateralization, although it has potential utility for predicting hemispheric dominance. This paper reports the development of a reliable (alpha = 0.89) 11-item behavioral inventory of foot preference. Since footedness and handedness are only partially related, both must be measured reliably to identify individuals who have a consistent right or left side preference. It has yet to be determined whether footedness or handedness has the stronger relationship to other aspects of cerebral lateralization and whether both measures together predict lateralization better than one of them alone.

Magical Ideation and Social Anhedonia as Predictors of Psychosis Proneness: A Partial Replication

The authors compared college students identified by high scores on the Magical Ideation Scale (M. Eckblad & L. J. Chapman, 1983) and the Revised Social Anhedonia Scale (MagSoc; n = 28; M. Eckblad, L. J. Chapman, J. P. Chapman, & M. Mishlove, 1982) with control participants (n = 20) at a 10-year follow-up assessment in an attempt to replicate L. J. Chapman, J. P. Chapman, T. R. Kwapil, M. Eckblad, and M. C. Zinsers (1994) report of heightened psychosis proneness in MagSoc individuals. The MagSoc group exceeded the control group on severity of psychotic-like experiences; ratings of schizotypal, paranoid, and borderline personality disorder symptoms; and rates of mood and substance use disorders. Two of the MagSoc participants but none of the control participants developed psychosis during the follow-up period (a nonsignificant difference). Consistent with L. J. Chapman et al.s findings, the groups did not differ on rates of personality disorders or relatives with psychosis.

Facilitation of word recognition by semantic priming in schizophrenia

Schizophrenic (n = 21), bipolar (n = 18), and normal control subjects (n = 21) were compared on a word recognition measure of semantic priming. The task involved the presentation of related, neutral, and unrelated word pairs; the second word (target word) in each pair was presented in a degraded form. Facilitation was defined as the accuracy of target word recognition for the related word pairs minus accuracy for the neutral word pairs. Titration, achieved by manipulating the degradation of the target word, was used to maintain each subjects overall accuracy for related and neutral items at approximately 50%. This procedure minimized the artifactual effects of overall accuracy on the difference score. Schizophrenics exceeded both normal control subjects and bipolar subjects on facilitation. Bipolar subjects did not differ from control subjects. The results support Mahers hypothesis that semantic priming effects are heightened in schizophrenia.

Impulsive nonconformity as a trait contributing to the prediction of psychotic-like and schizotypal symptoms.

A 51-item true-false Impulsive Nonconformity Scale was constructed to measure impulsive antisocial behavior of the sort often reported in the premorbid adjustment of some psychotics. Schizophrenics and schizoaffective patients (N = 46) scored higher on the scale than control (N = 76). An experimental group of 120 aberrantly high-scoring (2 SDs above the mean) college students and 176 control subjects were interviewed using modified versions of Weissman and Paykels Social Adjustment Scale interview and Spitzer and Endicotts Schedule for Affective Disorders and Schizophrenia-Lifetime Version (SADS-L). The experimental subjects reported more antisocial and nonconforming behaviors than control subjects, supporting the construct validity of the scale as a measure of impulsive nonconformity, and reported more psychotic or psychotic-like experiences, more schizotypal experiences, and more depressive and manic or hypomanic symptoms, suggesting that a portion of the experimental subjects may be at elevated risk for psychosis and/or major affective disorder. Subjects who score aberrantly high on both the Impulsive Nonconformity Scale and our earlier Perceptual Aberration-Magical Ideation Scale are more aberrant on several other measures of schizophrenic-like cognitive slippage than are subjects who score high on only one of the two scales.

Hemispheric asymmetries of function in patients with major affective disorders

Several investigators have suggested that affectively disordered patients have dysfunction of the nondominant cerebral hemisphere. The present study tested this hypothesis using psychometrically matched measures of verbal and visual-spatial skills. A sample of 64 psychiatric in-patients and out-patients was interviewed using an expanded and modified version of the NIMH Diagnostic Interview Schedule and diagnosed using the criteria of DSM-III-R, the Research Diagnostic Criteria, and the Feighner et al. system. Patients diagnosed as affectively disordered by at least one system were administered a pair of psychometrically matched measures: a measure of Word-Finding modeled after the Boston Naming Test, and a measure of visual-spatial functioning adapted from the Dot-Localization task. Patients with diagnoses of major depression by any of the three systems showed significantly poorer performance on Dot Localization than on Word Finding. Differences for patients with bipolar diagnoses were in the same direction but fell short of significance. These results support the hypothesis that patients with major depressive disorders may show impaired right-hemisphere functioning.

Does the Eysenck psychoticism scale predict psychosis? A ten year longitudinal study

534 college students were selected by their scores on several scales of psychosis proneness, were interviewed, and were given the Eysenck and Eysenck (1975) Psychoticism Scale (P-Scale). After 10 yr, 508 subjects were reinterviewed. Subjects identified by initial deviantly high scores on the P-Scale (N = 26) did not differ from control subjects (N = 310) on the rate of subjects who developed psychotic disorders or in reports of psychotic relatives. However, High P subjects exceeded controls on ratings of psychoticlike experiences and on symptoms of schizotypal and paranoid personality disorder. The findings indicate that high scorers on the P-Scale are psychoticlike but are not at heightened risk for psychosis.

Reliability and the discrimination of normal and pathological groups

The authors of a recent article (Neufeld, R. W. J., and Broga, M. I. Evaluation of information sequential aspects of schizophrenic performance. II. Research strategies and methodological issues. J. Nerv. Ment. Dis., 169: 569–579, 1981) questioned the usefulness of considering reliability and other psychometric characteristics of tasks in the comparison of the pathological and normal groups on the abilities measured by the tasks. They supported their conclusion by a reanalysis of data published by Chapman and Chapman (Chapman, L. J., and Chapman, J. P. Problems in the measurement of cognitive deficit. Psychol. Bull., 79:380–385,1973). We contend that their conclusion was based on an inappropriate analysis of the data with a neglect of relevant psychometric principles.