Bias in the use of base rates: Racial prejudice in decision-making

Two studies investigated biases in the use of base rate information when assessing the probability of a witness' accurate identification of a white or West Indian as a burglar. An adapted version of the Kahneman-Tversky cab problem was used, to provide a social decision in which biases could be measured against some normative standard. Ethnicity of youth (white/West Indian) and nature of base rate (incidental/causal) were manipulated in a 2 × 2 between-subjects design. A significant interaction effect revealed that subjects took no account of the base rate for a West Indian subject, but used the base rate only when it was causal and the youth was white. This ‘prejudice effect’ against a West Indian youth and ‘exoneration effect’ for a white youth were replicated in a second study, using a microcomputer and chronometric analyses. Results are discussed in terms of heuristic decision-making, social schemata, and the cognitive versus motivational bases of bias in the use of base rates.     

Insight-oriented group psychotherapy of latency-age children in an acute care setting

Traditional approaches to group therapy with latency-age children have stressed activity and nonverbal therapeutic interventions. These approaches originated in the 1940s with Slavson's activity aroup therapy. A review of the literature of the past 25 years reveals that many clinicians have increasingly employed verbal techniques with latencyage groups. Most such reports describe groups for latency-age out-patients. In this paper, a verbal, interpretive technique for group therapy with latency-age inpatients is described. Clinical vignettes are included to illustrate this technique. Our experience suggests that such a technique can become an integral part of the inpatient treatment program for the latency-age child.     

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.     

Do recognizable figures enjoy an advantage in binocular rivalry?

Five experiments examined whether recognizable stimuli predominate in binocular rivalry. It was found that a face predominated more than did a pattern equated for spatial frequency, luminance, and contrast; an objective reaction time procedure confirmed predominance of the face. The face was still liable to fragmentation as stimulus size increased. Observers tracked exclusive dominance of a picture of a camouflaged figure (a Dalmatian dog) prior to and then following discovery of the figure's presence; control observers received the same protocol with a scrambled version of the dog stimulus. Compared with control results, predominance of the dog picture was higher even before observers knew of the camouflaged figure. Inversion of the dog figure reduced its predominance. Binocular rivalry is sensitive to object-related, configural properties of a stimulus.     

On the Relation Between Time Perception and the Timing of Motor Action: Evidence for a Temporal Oscillator Controlling the Timing of Movement

Studies of time estimation have provided evidence that human time perception is determined by an internal clock containing a temporal oscillator and have also provided estimates of the frequency of this oscillator (Treisman, Faulkner, Naish, & Brogan, 1992; Treisman & Brogan, 1992). These estimates were based on the observation that when the intervals to be estimated are accompanied by auditory clicks that recur at certain critical rates, perturbations in time estimation occur. To test the hypothesis that the mechanisms that underlie the perception of time and those that control the timing of motor performance are similar, analogous experiments were performed on motor timing, with the object of seeing whether evidence for a clock would be obtained and if so whether its properties resemble those of the time perception clock. The prediction was made that perturbations in motor timing would be seen at the same or similar critical auditory click rates. The experiments examined choice reaction time and typing. The results support the hypothesis that a temporal oscillator paces motor performance and that this oscillator is similar to the oscillator underlying time perception. They also provide an estimate of the characteristic frequency of the oscillator.     

The gestural repertoire and its evolution over the second year

The entire repertoire of communicative gestures was documented in a longitudinal, observational study of 10 infants, whose combined ages covered the range from 9 to 22 months. Early in the second year, giving as a request to do something with the object increased, while emotive gestures decreased. Later in the second year, pointing gestures increased, while protest gestures tended to decrease. Combining gestures with vocalization tended to increase only for protest gestures later in the second year. Eye contact showed a small but continuous increase in coordination with gestures over the second year, particularly with comment, request, and emotive gestures. These findings indicate an increasing use of the parent as an agent and of the informative function in non-verbal communication during this period of transition to verbal communication.