Influences of hand posture and hand position on compatibility effects for up-down stimuli mapped to left-right responses: evidence for a hand referent hypothesis

Unimanual left-right responses to up-down stimuli show a stimulus-response compatibility (SRC) effect for which the preferred mapping varies as a function of response eccentricity. Responses made in the right hemispace and, to a lesser extent, at a midline position, are faster with the up-right/down-left mapping than with the up-left/down-right mapping, but responses made in the left hemispace are faster with the up-left/down-right mapping. Also, for responses at the midline position, the preferred mapping switches when the hand is placed in a supine posture instead of the more usual prone posture. The response eccentricity effect can be explained in terms of correspondence of asymmetrically coded stimulus and response features, but it is not obvious whether the hand posture effect can be explained in a similar manner. The present study tested the implications of a hypothesis that the body of the hand provides a frame of reference with respect to which the response switch is coded as left or right. As was predicted by this hand referent hypothesis, Experiment 1 showed that the influence of hand posture (prone and supine) on orthogonal SRC was additive with that of response location. In Experiment 2, the location of the switch relative to the hand was varied by having subjects use either a normal grip in which the switch was held between the thumb and the index finger or a grip in which it was held between the little and the ring fingers. The magnitudes of the mapping preferences varied as a function of the grip and hand posture in a manner consistent with the hand referent hypothesis.     

Perception of objects that are translating and rotating

The motion of objects that are both translating and rotating can be decomposed into an infinite number of translational and rotational combinations. How, then, do such stimuli routinely elicit specific percepts and behavioral responses that are usually appropriate? A possible answer is that motion percepts are fully determined by the probability distributions of all the possible correspondences and differences in the stimulus sequence. To test the merits of this conceptual framework, we investigated the perceived motion elicited by a line that is both translating and rotating behind an aperture. When stimuli are presented such that a particular sequence of appearance and disappearance occurs at the aperture boundary, subjects report that the line is rotating only; furthermore, the perceived centers of rotation appear to describe a cycloidal trajectory, even when one aperture shape is replaced by another. These and other perceptual effects elicited by translating and rotating stimuli are all accurately predicted by the probability distribution of the possible sources of the physical movements, supporting the conclusion that motion perception is indeed generated by a wholly probabilistic strategy.     

Framing interethnic ideology: effects of multicultural and color-blind perspectives on judgments of groups and individuals

In 3 experiments, White American college students received a message advocating either a color-blind or a multicultural ideological approach to improving interethnic relations and then made judgments about various ethnic groups and individuals. Relative to a color-blind perspective, the multicultural perspective led to stronger stereotypes, greater accuracy in these stereotypes, and greater use of category information in judgments of individuals. This increase in between-category differentiation occurred both for attributes that favored the in-group and for attributes that favored the out-group and was also paired in some cases with greater overall positivity toward the out-group. The findings lead us to question the implicit assumption driving the majority of social psychological efforts at prejudice reduction: that the categorization process leads to prejudice, and that the relevance of social categories must therefore be de-emphasized.     

Reliability and dimensionality of judgments of visually textured materials

We extended perceptual studies of the Brodatz set of textured materials. In the experiments, texture perception for different texture sets, viewing distances, or lighting intensities was examined. Subjects compared one pair of textures at a time. The main task was to rapidly rate all of the texture pairs on a number scale for their overall dissimilarities first and then for their dissimilarities according to six specified attributes (e.g., texture contrast). The implied dimensionality of perceptual texture space was usually at least four, rather than three. All six attributes proved to be useful predictors of overall dissimilarity, especially coarseness and regularity. The novel attribute texture lightness, an assessment of mean surface reflectance, was important when viewing conditions were wide-ranging. We were impressed by the general validity of texture judgments across subject, texture set, and comfortable viewing distances or lighting intensities. The attributes are nonorthogonal directions in four-dimensional perceptual space and are probably not narrow linear axes. In a supplementary experiment, we studied a completely different task: identifying textures from a distance. The dimensionality for this more refined task is similar to that for rating judgments, so our findings may have general application.     

Correction for range restriction: an expanded typology

A common research problem is the estimation of the population correlation between x and y from an observed correlation rxy obtained from a sample that has been restricted because of some sample selection process. Methods of correcting sample correlations for range restriction in a limited set of conditions are well-known. An expanded classification scheme for range-restriction scenarios is developed that conceptualizes range-restriction scenarios from various combinations of the following facets: (a) the variable(s) on which selection occurs (x, y and/or a 3rd variable z), (b) whether unrestricted variances for the relevant variables are known, and (c) whether a 3rd variable, if involved, is measured or unmeasured. On the basis of these facets, the authors describe potential solutions for 11 different range-restriction scenarios and summarize research to date on these techniques.     

Culture and the economy

In a sample of 18 industrialized nations, measures of national character did not improve the power of socioeconomic variables in predicting unemployment rates.     

Demographic, clinical, and neurocognitive correlates of everyday functional impairment in severe mental illness

Although cognitive deficits often accompany severe mental illness, their implications for everyday functioning remain poorly understood. In this study, an occupational therapist (OT) rated the everyday functioning of 105 adult psychiatric patients. Using demographic, clinical, and cognitive variables, the authors tested alternative models to account for the observed variability in OT ratings. Although age, education, and the presence of schizophrenia each contributed to a model that accounted for 27% of the variation in functional independence, adding terms for auditory divided attention and verbal learning increased the proportion of explained variance to 45% and decreased the beta weights for age and education--but not schizophrenia--to nonsignificant levels. These findings demonstrate the relevance of cognitive performance to everyday functioning in severe mental illness. They are discussed with respect to hypothesized determinants of psychiatric disability.     

Ministry to the chronic hemodialysis patient

The beginning point of ministry to those persons suffering from renal failure and turning to hemodialysis in order to sustain life is a sensitive understanding of the total dialysis experience. The minister or chaplain who visits a hemodialysis unit only occasionally will be more effective in bringing his skills to the task by understanding the unique dynamics of the physical, emotional and spiritual adjustment of those who depend on this relatively new therapy. The specific elements of this ministry in terms of those closely involved, professional care givers, families, and patients, are discussed with attention to the factors that tend to make ministry to the hemodialysis patient unique.This article is the result of a one-year chaplain residency at the Veterans Administration Hospital in Nashville, Tennessee, in partial fulfillment of clinical requirements for the D. Min. degree in Pastoral Theology and Counseling at the Divinity School, Vanderbilt University, Nashville, Tennessee.     

Effect of arousal and retention delay on memory: a meta-analysis

Two meta-analyses were conducted to examine the magnitude of the interaction between arousal and retention delay on various types of memory, e.g., verbal, visual, etc., as initially reported by Kleinsmith and Kaplan in 1963 and 1964. Results of the first meta-analysis (29 studies, N = 2,637) indicated that the interaction was robust (d = .779), with low arousal leading to better immediate memory than high arousal, whereas high arousal led to better delayed memory than low arousal. Incorporating additional studies, a subsequent meta-analysis (48 studies, N = 3,143) on the effect of arousal on memory, taking retention delay as a moderator, provided further support. At a 2-min. delay, low arousal led to better immediate memory than high arousal (d = -.459). This difference decreased at a 20-min. delay (d = .106), when directions of high and low arousal effects on memory appeared to reverse. At longer delays than 20 min., high arousal led to better delayed memory than low arousal (ds = .753, .219, and .472, for delays of 45-min., 1-day, and more than 1-day, respectively).     

自我面孔识别的独特性

与识别他人的面孔相比,自我面孔识别在行为反应、种系发生、个体发展以及脑机制等方面都具有很大的独特性。行为指标方面,自我面孔识别在速度上快于识别他人的面孔;种系发生方面,只有人类和大猩猩等高级灵长类动物才具有识别自己面孔的能力;个体发展方面,儿童出生后不久即能识别他人面孔,但要在18个月左右才能表现出自我面孔识别能力;脑机制方面,神经心理学和脑成像研究结果表明自我面孔识别可能主要是右脑的功能。该领域的研究进展将为深入了解自我的形成机理提供一个新的探视“窗口”。