Perceived discrimination in the context of multiple group memberships

This study examined the joint impact of gender and ethnicity on expectations of general discrimination against oneself and one's group. According to the double–jeopardy hypothesis, women of color will expect to experience more general discrimination than men of color, White women, and White men because they belong to both a low–status ethnic group and a low–status gender group. Alternatively, the ethnic–prominence hypothesis predicts that ethnic–minority women will not differ from ethnic–minority men in their expectations of general discrimination because these expectations will be influenced more by perceptions of ethnic discrimination, which they share with men of color, than by perceptions of gender discrimination. All results were consistent with the ethnic–prominence hypothesis rather than the double–jeopardy hypothesis.     

How many variables can humans process?

The conceptual complexity of problems was manipulated to probe the limits of human information processing capacity. Participants were asked to interpret graphically displayed statistical interactions. In such problems, all independent variables need to be considered together, so that decomposition into smaller subtasks is constrained, and thus the order of the interaction directly determines conceptual complexity. As the order of the interaction increases, the number of variables increases. Results showed a significant decline in accuracy and speed of solution from three-way to four-way interactions. Furthermore, performance on a five-way interaction was at chance level. These findings suggest that a structure defined on four variables is at the limit of human processing capacity.     

Time Perception: Modality and Duration Effects in Attention-Deficit/Hyperactivity Disorder (ADHD)

Time perception performance was systematically investigated in adolescents with and without attention-deficit/hyperactivity disorder (ADHD). Specifically, the effects of manipulating modality (auditory and visual) and length of duration (200 and 1000 ms) were examined. Forty-six adolescents with ADHD and 44 controls were administered four duration discrimination tasks and two control tasks, and a set of standardized measures. Participants with ADHD had higher thresholds than controls on all of the duration discrimination tasks, with the largest effect size obtained on the visual 1000 ms duration discrimination task. No group differences were observed on the control tasks. Visual–spatial memory was found to be a significant predictor of visual and auditory duration discrimination at longer intervals (1000 ms) in the ADHD sample, whereas auditory verbal working memory predicted auditory discrimination at longer intervals (1000 ms) in the control sample. These group differences suggest impairments in basic timing mechanisms in ADHD.     

Joint custody and the preschool child

A longitudinal study of 25 families, with children aged 14 months-5 years, in joint custody, is reported. Varying motivations that lead divorcing parents to undertake and sustain joint custody are discussed, together with the stresses and gratifications of these arrangements for the parents and children. Findings are that where both parents are motivated primarily by interest in the child, where the parenting is sensitive and where the child is shielded from interparental conflict, young children do well. Such families were not the majority in this study. Significant differences emerged in the adjustment of the 1–3 age group as compared with the 3–5 age group which point to greater difficulties for the 3–5-year-olds.     

Do background luminances interact during binocular fusion?

The question investigated in the experiments reported here was whether monocular background luminances sum during binocular fusion. Fusion was made explicit by using a random-dot stereogram (RDS) as a background stimulus. In the presence of the RDS, differential luminance thresholds were somewhat higher than in the uniform field: a full-field, binocular dot array acted as a mask for a full-field luminance change, but global depth had no effect at threshold. The amount of the binocular advantage at threshold was compared to the basic "threshold response," that is, the change in threshold resulting from raising the background luminance by a factor of 2. It was found that the amount of the binocular advantage was equivalent, on the average, to some 75% of the threshold response--significantly less than the 100% predicted by "simple summation." The amount of the binocular advantage varied substantially among observers and eyes, whereas the threshold response obeyed Weber's law in all cases: the variability was eye-, rather than threshold-dependent. Monocular thresholds did not decrease when taken with the nontest eye occluded rather than viewing a fused background. The proposition that the adaptation state of the visual system is increased during binocular fusion (Cogan, 1982) was not supported. Yet occluding the nontest eye, rather than presenting the test stimulus monocularly against a fused background, did change monocular thresholds in some eyes and observers. These findings are interpreted as evidence for a complex binocular background interaction involving both summation and inhibition.     

Memories of labor and birth: reliability of post partum questionnaire reports

The stability of reports of feelings during vaginal births was assessed in three studies. In Study I, post partum reports from 475 primiparous women who participated in a childbirth preparation program were compared to identify differences between reports completed from the day of the birth to more than six weeks after the birth. In Study II, the post partum reports of 46 primiparous and 95 multiparous women completed 1, 3, or 6 mo. after giving birth were compared. In Study III, test-retest reliabilities were calculated for post partum reports completed by 22 primiparous and 16 multiparous women during the 5th and 7th post partum weeks. In these studies, reports of pain during labor were stable.     

Methylphenidate and cognitive flexibility: Dissociated dose effects in hyperactive children

A randomized, double-blind, placebo-controlled trial was conducted to assess the acute effects of placebo and three doses of methylphenidate (MPH) (0.3, 0.6, 0.9 mg/kg) on cognitive flexibility and overt behavior in 28 children with a confirmed diagnosis of attention deficit-hyperactivity disorder. Two underlying cognitive processes (response inhibition and response reengagement) were assessed by measuring the probability and speed with which subjects could inhibit responses to a primary task (forced-choice letter discrimination) and immediately execute a response to a secondary task (simple reaction time) when given a signal to do so. Results indicated that MPH enhanced cognitive flexibility, although the high dose was less effective than lower doses in enhancing response inhibition. Dissociations of dose effects on cognitive function and behavior were demonstrated: Dose-response functions for changes in behavior were linear, whereas the function for response inhibition was U-shaped. Findings argue against the typical clinical practice of determining the response to stimulant treatment from a single measure such as parent report of child behavior.