Stimulus-independent thought depends on central executive resources

Stimulus-independent thoughts (SITs) are streams of thoughts and images unrelated to immediate sensory input. Four experiments examined the contribution of aspects of working memory to production of SITs. In Experiments 1 and 2, interventions that were targeted on, respectively, phonological and visuospatial components of working memory both interfered with production of SITs, but there was evidence that these tasks also made demands on central executive resources. Experiments 3 and 4 specifically examined the hypothesis that production of SITs and control of nonproceduralized tasks both depend on central executive resources, and so should show mutual interference. In Experiment 3, prior practice on pursuit rotor and memory tasks reduced the interference with SITs from concurrent task performance. In Experiment 4, randomness within a task involving random-number generation was less when SITs were being produced concurrently than it was when they were not. The results suggest that production of SITs depends on central executive resources.     

The Diagnostic Interview Schedule for Children (PC-DISC v.3.0): Parents and Adolescents Suggest Reasons for Expecting Discrepant Answers

To identify reasons for discrepancies between parent and child reports of child/adolescents's psychiatric symptoms, parents and adolescents (51 pairs) were asked to guess what the other would answer to questions from the PC-DISC about the adolescent's psychiatric symptoms, and to explain why they expected disagreement when the answer they provided for the other was different from their own. Adolescents' explanations for expecting (1) parental denial of symptoms the adolescent reported were: the parent was unaware of, forgot about, assumed the adolescent could not have, or trivialized the symptom; and (2) parental report of symptoms the adolescent denied were: the parent misread or exaggerated the adolescent's symptom, had too high expectations for the adolescent's behavior, put a negative label on or did not trust the adolescent. Parents' reasons for expecting their children to (1) deny symptoms the parents reported were: the adolescent did not remember how s/he felt, lied, did not recognize or minimized the importance or frequency of the symptom; and (2) report symptoms the parents denied were: the adolescent lied, exaggerated the importance of or interpreted the symptom differently.Support for this work was provided by National Institute of Drug Abuse grant number DA-05585 (Dr. Cottler, P.I.), and National Institute of Mental Health grants numbers MH-31302 (Dr. R. C. Cloninger, P.I.) and MH-17104 (Dr. Cottler, P.I.).Address all correspondence, including reprint requests, to Michelle Bidaut-Russell, Ph.D, MPH, MPE, Department of Psychiatry, Box 8134, Washington University School of Medicine, 4940 Children's Place, St. Louis, Missouri 63110.     

Dissipating the quantum measurement problem

The integration of recent work on decoherence into a so-called modal interpretation offers a promising new approach to the measurement problem in quantum mechanics. In this paper I explain and develop this approach in the context of the interactive interpretation presented in Healey (1989). I begin by questioning a number of assumptions which are standardly made in setting up the measurement problem, and I conclude that no satisfactory solution can afford to ignore the influence of the environment. Further, I argue that there are good reasons to believe that on a modal interpretation environmental interactions rapidly ensure that a quantummechanically describable apparatus indeed records a definite result following a measurement interaction.     

Can skilled performers readily change technique? An example, conventional to wave action breaststroke

There has been a paucity of research that has investigated whether skilled performers of a complex sports skill can readily change their technique. This study was designed to investigate whether swimmers skilled in the conventional breaststroke technique could adjust readily to the wave action technique. Nine masters swimmers with well established and stable movement patterns for the conventional technique were coached in the wave action breaststroke technique. The swimmers were videotaped from the side during maximum speed trials of the conventional breaststroke technique before coaching and the wave action technique after ten 45-minute coaching sessions. The amplitude and phase of the waveforms comprising the vertical displacements of the body parts were determined by Fourier analysis. In response to the coaching, the amplitude of the fundamental frequency of the vertex of the head, shoulders, hips, and knees increased significantly (p < 0.01). The percentage of power contained in the fundamental frequency of the shoulder and hip vertical displacements also increased significantly (p < 0.01). All subjects changed the relative phase of the fundamental frequencies of the vertex, shoulder, and hip vertical displacements. It was concluded that in this complex skill, major changes to the low frequency waveforms comprising the motion were achieved readily.     

Util-izing animals

ABSTRACT Biomedical experimentation on animals is justified, researchers say, because of its enormous benefits to human beings. Sure, animals suffer and die, but that is morally insignificant since the benefits of research incalculably outweigh the evils. Although this utilitarian claim appears straightforward and relatively uncontroversial, it is neither straightforward nor uncontroversial. This defence of animal experimentation is likely to succeed only by rejecting three widely held moral presumptions. We identify these assumptions and explain their relevance to the justification of animal experimentation. We argue that, even if non-human animals have considerably less moral worth than humans, experimentation is justified only if the benefits are overwhelming. By building on and expanding on arguments offered in earlier papers, we show that researchers cannot substantiate their claims on behalf of animal research. We conclude that there is currently no acceptable utilitarian defence of animal experimentation. Moreover, it is unlikely that there could be one. Since most apologists of animal experimentation rely on utilitarian justifications of their practice, it appears that biomedical experimentation on animals is not morally justified .     

Evaluation of a “mental effort” hypothesis for correlations between cortical metabolism and intelligence

Previous research indicates that low scores on the Raven's Advanced Progressive Matrices (RAPM) test are associated with increased cortical glucose utilization during problem solving. We hypothesized that previous results may reflect the neurophysiological consequences of patterns of effort requirements; that is, high-effort expenditure from lower aptitude participants (for whom the problems are hard) and low-effort expenditure from higher aptitude participants (for whom the problems are easy). In this experiment, positron emission tomography (PET) data were gathered on participants (N = 28) who solved easy and hard problems that were tailored to the participants' own ability levels, thereby eliminating aptitude group differences in effort requirements. Contrary to previous results, high aptitude was associated with high cortical glucose use. Average aptitude participants showed diminished glucose use in the hard condition. A significant Group X Condition X Hemisphere Effect was also noted, with greater right hemisphere activation in the hard condition for the high-aptitude group. These results demonstrate that the relation of cerebral glucose use and cognitive ability is sensitive to participant and task selection.     

The content of mother stereotypes

Although there is considerable empirical support for the existence of social stereotypes about different types of mothers, the content of those stereotypes is less clear. The purpose of this study was to identify the content of stereotypes related to different types of mothers. Stereotyped attributes of married mothers, stepmothers, divorced mothers, and never married mothers were generated by several samples and combined into one list. A subsequent sample was asked to indicate the percentage of each type of mother possessing each characteristic. The content of mother stereotypes was examined, and the results discussed in light of effects on social interactions, the self-image of women, and future attempts to assess family-related stereotypes.     

Perception of sexual intent: The role of gender,alcohol consumption,and rape supportive attitudes

This study examined the effects of participant's gender, participant's rape supportive attitudes, and target's alcohol consumption on participant's perceptions of target's sexual intent. Female and male college students read vignettes in which a young woman and man who were socializing consumed either alcoholic or nonalcoholic beverages. At the studied university, approximately 86% of undergraduates were Caucasian, 8% were African American, 3% were Asian, and 3% had other ethnic backgrounds. As hypothesized, men perceived female targets as behaving more sexually than did women, especially men high in rape myth acceptance. Male and female targets' alcohol consumption interacted, such that when both individuals were drinking alcohol they were perceived as being most sexual and their drinking was viewed as most appropriate. The rape myth acceptance and alcohol findings are discussed in terms of their implications for sexual assault and substance abuse prevention programming.Many thanks to Mary Jo Smith for assistance with data management and analyses. ARBOR staff provided assistance with data coding.     

Size and orientation of objects in explicit and implicit memory: A reversal of the dissociation between perceptual similarity and type of test

Memory of size and orientation of objects was tested in explicit and implicit memory tests. Explicit memory was tested by object recognition and by recognition of the congruency of the changed sensory features. Implicit memory was tested by size assessment (Exps. 1 and 2), orientation judgement (Exps. 4 and 5), picture-fragment naming (Exp. 6), and classification (Exps. 3 and 7). Memory of sensory features was investigated by the comparison of performances of test-congruent with test-incongruent stimuli (i.e., same size or orientation vs. different size or orientation). The main result was a dissociation between these two tasks pertaining to the influence of sensory congruency on performance. However, it was in opposition to the usual relationship between the type of test and the perceptual similarity from study to test. In this study explicit, but not implicit, memory depended on sensory congruency. In the explicit tests performances were better when the stimuli were congruent than when they were incongruent. In the implicit test this variation had no influence. To get a repetition effect, it was important only that the object was repeated, and the size of this effect did not depend on sensory congruency. However, a change in another sensory feature — distortions of shape — strongly influenced the size of the repetition effect in the implicit test. Neither transfer-appropriate processing nor a system approach can easily explain this pattern of results. A multi-level, multi-token model is proposed to account for the different effects of sensory features in explicit and implicit memory.