Controlling the Ground Reaction Force During Lifting

The control of the ground reaction force vector relative to the center of gravity (CoG) was examined while subjects performed a back-lifting task. Six male subjects (aged 24.0 +/- 2.5 years) repeatedly lifted a barbell. A biomechanical analysis that used a linked segment model revealed that the summed rotations of body segments during lifting yielded a specific rate of change of the angular momentum of the entire body. This equaled the external moment provided by Fsubg; relative to CoG. This implies that multisegment movements involve control of the angular momentum of the entire body through an appropriately directed Fsubg;. Thus, in dynamic tasks Fsubg; is pointed away from rather than lined up with the CoG, as is the case in static tasks.     

Evaluating the Impact of a National AIDS Prevention Radio Campaign in St. Vincent and the Grenadines1

Based on extensive formative research in the three Eastern Caribbean countries of St. Lucia, St. Vincent and the Grenadines, and Grenada (Fishbein, Middlestadt, & Trafimow, 1993; Fishbein, Trafimow, et al., 1993), a three-nation, mass media, condom use campaign was developed. In order to assess the impact of the campaign, a follow-up survey was conducted in St. Vincent and the Grenadines. This paper examines the effectiveness of the campaign by comparing responses on this survey by respondents who were or were not exposed to the campaign. A statistically significant impact of exposure to the campaign was obtained, indicating that a well-designed, empirically based, mass media campaign can be an effective tool in the battle to prevent the spread of AIDS.     

Creative Problem-Solving in Art: A Model for Idea Inception and Image Development

A model for creative problem-solving specific to the creation of art is proposed. The development of the Osborn-Parnes and Isaksen-Treffinger models are reviewed. An adaptation of the Osborn-Parnes/Isaksen-Treffinger models is presented. The Model for Idea Inception and Image Development in Art is presented with five primary stages: Associative Exploration, Problem Parameter Exploration, Multiple Focus Exploration, Primary Focus Exploration and Refinement. Transitional stages are delineated. The significance and implications of the model for artists, students and instructors in art education are discussed.     

The psychology of christian prayer: a review ofempirical research

This paper presents, discusses and evaluates empirical studies concerned with Christian prayer. These studies are classified within four main areas. The first area concerns what is known about the practice of prayer from empirical surveys and demonstrates that a much higher proportion of people pray privately than attend public places of worship. The second area concerns what is known about changing patterns of prayer during childhood and adolescence and argues that these changes need to be interpreted within the context of both developmental and social psychology. The third area concerns the subjective effects of prayer, beginning with Galton's early observations concerning the comparative longevity of the clergy (who are regarded as praying people) and including more recent studies of the psychological correlates of self-reported prayer, like personal well-being and purpose in life. It is concluded that, while such studies may demonstrate the beneficial nature of prayer, they cannot demonstrate the causal efficacy of prayer. The fourth area concerns the objective effects of prayer, beginning with Galton's early observations concerning the absence of comparative longevity among royalty (who are regarded as prayed for people) and including more recent studies of the growth correlates of prayer for pot plants. It is concluded that such studies currently provide contradictory evidence. It is recommended that further research in the field needs both to observe the strict criteria of objective empirical research and to be alert to theological nuances regarding the actual claims made for the efficacy of prayer within the community of believers.     

Division of labor in conversations: Are Fishman's results replicable and generalizable?

Fishman's (1978a) conclusion that women do the bulk of the support work in their conversations with male partners has had widespread appeal. In this article, we present the results of two studies designed to assess the generalizability and replicability of her findings. In Study 1. the get-acquainted conversations of 20 mixed-sex, 10 male same-sex, and 10 female same-sex dyads were analyzed for the support strategies identified by Fishman. No support for a sexual division of labor was found. In Study 2, we analyzed the casual, at-home conversations of 17 intimate male-female couples. Again, we found no evidence that the women used more of the support strategies than their male partners. Rather, our findings suggest that the women may have helped to sustain the conversations with their male partners simply by talking more. The appeal of Fishman's conclusions in the absence of empirical evidence suggests that she has touched on a mythic truth.This article is based on a Master's thesis by the second author (Study 1) and an Honour's thesis by the third author (Study 2) under the supervision of the first author.     

Uncertainty in estimating distances from memory

Magnitude estimations involving spatial characteristics, such as distance, typically show a compressive function when estimates are made from memory. In particular, as the magnitude of a property grows larger and larger, estimates become more and more inaccurate, with increasing underestimates of the actual magnitude. Previous theories have attempted to explain this difference by supposing that magnitude estimation was accomplished through a reperceptual process, in which the errors of perception are magnified, or a transformation process, in which the memory trace undergoes a consistent alteration toward a more schematic form. The present experiments present evidence in support of an uncertainty hypothesis. When subjects are uncertain of the actual value of a distance, they are forced to guess on the basis of the mean distance they encountered, because they are unable to retrieve the information accurately. When they can retrieve the information, they are more certain and their estimates are more accurate. This hypothesis was also extended to integrative conditions in which the subjects were presented with the stimulus display in a piecemeal fashion. In these cases, distance estimates were derived by combining spatial representations. This method of presentation caused distance estimates to become less accurate.     

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.