An assessment of the Edwards Personal Preference Schedule from the perspective of the five-factor model.

We examined the validity of need scales of the Edwards Personal Preference Schedule (EPPS) by correlating them with a measure of the five basic factors of personality; we also considered test format as a possible source of invalidity. Three hundred thirty (223 women, 107 men) undergraduate students completed both the NEO Personality Inventory (NEO-PI)--a measure of the five factors--and one of two versions of the EPPS. Results show that both ipsative and normative versions of the EPPS could be meaningfully interpreted within the five-factor model, although the ipsative, forced-choice format of the standard EPPS apparently lowered validity coefficients and decreased convergent and discriminant validity. We argue that the five-factor model can provide a useful interpretive context for evaluating many clinical measures.     

The effect of hypnotically elicited testimony on jurors' judgments of guilt and innocence.

Survey data from several countries indicate that many people believe that hypnosis may increase the accuracy of an eyewitness's memory; most experimental research, however, suggests that this belief is inaccurate. This study examined whether the belief could influence judgments of guilt and innocence in a simulated criminal trial. The results indicated that British undergraduates were more likely to find a male defendant guilty when told that the testimony against him had been elicited under hypnosis. Results concerning a nonhypnotic memory facilitation technique were found to be inconclusive, and the salience of hypnotically elicited testimony was ruled out as a contributory element.     

Effects of response requirement and alcohol on human aggressive responding.

Nine men participated in two experiments to determine the effects of increased response requirement and alcohol administration on free-operant aggressive responding. Two response buttons (A and B) were available. Pressing Button A was maintained by a fixed-ratio 100 schedule of point presentation. Subjects were instructed that completion of each fixed-ratio 10 on Button B resulted in the subtraction of a point from a fictitious second subject. Button B presses were defined as aggressive because they ostensibly resulted in the presentation of an aversive stimulus to another person. Aggressive responses were engendered by a random-time schedule of point loss and were maintained by initiation of intervals free of point loss. Instructions attributed these point losses to Button B presses of the fictitious other subject. In Experiment 1, increasing the ratio requirement on Button B decreased the number of ratios completed in 4 of 5 subjects. In Experiment 2, the effects of placebo and three alcohol doses (0.125, 0.25, and 0.375 g/kg) were determined when Button B presses were maintained at ratio values of 20, 40 and 80. Three subjects who reduced aggressive responding with increasing fixed-ratio values reduced aggressive responding further at higher alcohol doses. One subject who did not reduce aggressive responding with increasing fixed-ratio values increased aggressive responding at the highest alcohol dose. The results of this study support suggestions that alcohol alters aggressive behavior by reducing the control of competing contingencies.     

Choice with delayed and probabilistic reinforcers: effects of variability, time between trials, and conditioned reinforcers.

In a discrete-trials procedure with pigeons, a response on a green key led to a 4-s delay (during which green houselights were lit) and then a reinforcer might or might not be delivered. A response on a red key led to a delay of adjustable duration (during which red houselights were lit) and then a certain reinforcer. The delay was adjusted so as to estimate an indifference point--a duration for which the two alternatives were equally preferred. Once the green key was chosen, a subject had to continue to respond on the green key until a reinforcer was delivered. Each response on the green key, plus the 4-s delay that followed every response, was called one "link" of the green-key schedule. Subjects showed much greater preference for the green key when the number of links before reinforcement was variable (averaging four) than when it was fixed (always exactly four). These findings are consistent with the view that probabilistic reinforcers are analogous to reinforcers delivered after variable delays. When successive links were separated by 4-s or 8-s "interlink intervals" with white houselights, preference for the probabilistic alternative decreased somewhat for 2 subjects but was unaffected for the other 2 subjects. When the interlink intervals had the same green houselights that were present during the 4-s delays, preference for the green key decreased substantially for all subjects. These results provided mixed support for the view that preference for a probabilistic reinforcer is inversely related to the duration of conditioned reinforcers that precede the delivery of food.     

Maximizing versus matching on concurrent variable-interval schedules

Maximization and matching predictions were examined for a time-based analogue of the concurrent variable-interval variable-ratio schedule. One alternative was a variable interval whose time base operated relatively independent of the schedule chosen, and the other was a discontinuous variable interval for which timing progressed only when selected. Pigeons switched between schedules by pecking a changeover key. The maximization hypothesis predicts that subjects will show a bias toward the discontinuous variable interval and undermatching; however the obtained results conformed closely to the predictions of the matching law. Finally, a quantitative comparison was made of the bias and sensitivity estimates obtained in published concurrent variable-interval variable-ratio analogue studies. Results indicated that only the ratio-based analogue of the concurrent variable interval variable ratio studied by Green, Rachlin, and Hanson (1983) produced significant bias toward the variable-ratio alternative and undermatching, as predicted by reinforcement maximization.     

Black South Africans and Canadians on neuroticism as a dimension of personality.

This study was done to assess gender and cultural differences on neuroticism as a dimension of personality among both Canadians and Black South Africans. No statistically significant cross-cultural differences were observed. However, statistically significant gender differences emerged among both Canadian and African men and women, with the latter scoring higher on neuroticism than the former.     

Choice of medical specialty: analysis of students' needs.

The purposes of this study were to assess the career development needs of entering medical students as measured by the Medical Career Development Inventory and to examine gender differences in responses to the inventory. A total of 115 entering medical students (representing two entering classes) took the inventory two months prior to matriculation. Analysis suggested that this sample of entering students had formed a vocational identity and that they had evaluated the suitability and viability of a commitment to a physician's career. However, the participants had not formed a clear picture of their specialty interest and goals. No significant gender differences were indicated. A recommended career assistance workshop is presented as appropriate for these students' needs.     

Type A behavior, job satisfaction, and stress among black professionals.

Most studies of work-related Type A behavior have been conducted with samples of white men. Using a mail questionnaire to assess Type A behavior, job satisfaction, and daily stress and tension among 250 black men and 233 black women public accountants, the prevalence of Type A behavior and its relationship with satisfaction and stress were highly consistent with those reported for other samples of white men and women.     

Interpretation style and reactance in counselor's social influence.

This study compared two different interpretation styles (tentative and absolute), two levels of subjects' reactance (high and low), and gender on the counselor's social influence, willingness to see the counselor, willingness to help, ability to help, and subjects' anger. No significant main effects or interaction were found for the counselor's social influence, but men in contrast to women perceived the counselor as more willing to help and indicated that they were more willing to see the portrayed counselor. Highly reactant subjects were more willing to see the counselor when absolute interpretations were used; they also thought the counselor was more willing to help when absolute interpretations were used, whereas low reactant subjects thought the counselor was more willing to help when tentative interpretations were used. Mixed results were found for subjects' anger.     

Validity and clinical scale comparisons between the MMPI and MMPI-2 with psychiatric inpatients.

This study was designed to investigate the comparability of the original MMPI (1950) and the MMPI-2 (1989) with a psychiatric patient population. 34 male and 3 female patients, shortly after admission to one of two acute psychiatry units, completed the old and revised versions of the MMPI. Paired t tests indicated but scant differences for raw scores, while many more differences were found among T scores for validity, clinical, and supplemental scales. Analyses, however, showed all scales on the two forms to be highly correlated. Analysis of the high-point and two-point codes across the two administrations also showed relative stability, although the proportion of Scales 2 (Depression) and 8 (Schizophrenia) decreased, while those for Scales 6 (Paranoia) and 7 (Psychasthenia) increased markedly in the MMPI-2 protocols. Examination of each version's discriminability among mood- and thought-disordered subsamples suggested that the MMPI provides slightly better delineation between diagnostic classes. Discriminant function analyses showed that there were essentially no differences between the two forms in the accurate classification of clinical and nonclinical groups. The findings reported here provide support for the MMPI-2; despite modification, the newer form retains the advantages of the original MMPI. Differences found here may be unique to psychiatric patients and their patterns of MMPI/MMPI-2 equivalence and may not generalize to other special populations.