Cognitive addition and multiplication: Evidence for a single memory network

In an experiment using verification task procedures, 100 subjects responded to simple and complex problems of addition and multiplication. Identical structural parameters were found to model reaction time accurately to both addition and multiplication problems. Slope estimates for a memory network parameter did not differ significantly between simple and complex problems within an operation or between addition and multiplication problems. Both complex addition and complex multiplication problems were processed columnwise, with column sums or products being retrieved from an interrated memory network. The two types of complex problems included similar processes for carrying and for encoding of single digits, and both were self-terminated when an error in the units column was encountered. Addition and multiplication facts appear to be retrieved from a single interrelated memory network. A conceptual model for this interrelated network is discussed.     

Scheduled running wheel activity indexes the specificity of pharmacological anorexia.

Nondeprived male Sprague-Dawley rats that were given scheduled access to running wheels for 60 min daily ran immediately and energetically. Intraperitoneal injections of 400 micrograms/kg pancreatic glucagon and 0.15 microgram/kg cholecystokinin octapeptide had no effect on scheduled running, but significantly inhibited feeding when the rats were offered condensed milk instead of access to the running wheels. This is consistent with the hypothesized function of these peptides as postprandial satiety signals. In contrast, 0.5 mg/kg amphetamine and 75 microM/kg LiCl, which produced similar degrees of anorexia, inhibited running by about 50%. Amphetamine, but neither peptide, also inhibited water drinking and disrupted the behavioral sequence of postprandial satiety. The distance run during scheduled running tests was inversely related to body weight, but the patterns of the drugs' effects were not altered by baseline running differences. Scheduled wheel running is a robust consummatory behavior that appears to provide a relatively valid, simple, and sensitive test of the behavioral specificity of pharmacological anorexia.     

Metamemory and academic achievement: testing the validity of a group-administered metamemory battery

This study was designed to assess the validity of a recently introduced group-administered battery of metamemory tasks for children and to concurrently assess the relationship between performance on these tasks and academic achievement for second- and fourth-grade normal and learning-disabled (LD) children. Consistent with theoretical predictions and with results from individually administered metamemory tasks, significant age-related performance differences were found for four of the battery's five subtests. However, three of these four performance differences appeared to be due to a floor effect--that is, the second graders performed at chance levels for all but one of the subtests. Nevertheless, modest zero-order correlations between academic achievement measures and scores on metamemory subtests, which did show interpretable age-related performance differences, were found, as were significant group (normal versus LD) differences for fourth graders. In all, these results provided some support for the validity and the utility of the group-administered metamemory battery, although the performance of young children must be interpreted with caution.     

The Mezzich MMPI regression formula revisited

In a sample of depressed psychiatric inpatients, the Mezzich regression formula, based on five MMPI scales, correlated moderately with clinicians' judgments and yielded few false negative diagnoses in identifying patients with unipolar Major Depressive Disorder, but was less effective in eliminating false positives.     

The irrelevant sound effect: does speech play a special role?

Memory for order is markedly impaired by the presence of irrelevant sound, even though participants are instructed to ignore the sound. Although a great deal of research has disclosed some features of the task and of the sound that augment or reduce the degree of interference, one important issue of the irrelevant sound effect not yet resolved is whether speech has a special status. This study revealed, within a design of adequate power, that the same physical stimulus (sine wave speech), whether perceived as speech or as nonspeech sound, produces similar degrees of disruption and is less disruptive of serial recall than natural speech. This outcome suggests that the acoustic constituents of sound rather than its source are most influential in determining the impact of irrelevant material.     

A life history assessment of early childhood sexual abuse in women

Life history theory provided a framework for examining the relations among child sexual abuse (CSA), childhood adversity, and patterns of reproductive development and behavior. A community survey that assessed CSA, life history variables (e.g., age of menarche), and social and family background was administered to 623 women (mean age=26.9 years). Independent of social and family background, CSA was associated with earlier age of (a) menarche, (b) first sexual relationship, (c) desire to have children, (d) first childbirth, and (e) lower self-evaluated physical attractiveness. Cluster analyses revealed different patterns of experiential correlates of reproductive development within the group of abused women, suggesting CSA may operate in combination with other childhood circumstances to modify the timing and pattern of individual maturation.     

Precise positioning of tachistoscopic stimuli with Scientific Prototype slide changers

An easily made device for eliminating horizontal movement of stimuli in Scientific Prototype slide changers is described. This device does not permanently alter the tachistoscope and does not interfere with normal operation of the slide changer.