Object recognition contributions to figure-ground organization: Operations on outlines and subjective contours

In previous research, replicated here, we found that some object recognition processes influence figure-ground organization. We have proposed that these object recognition processes operate on edges (or contours)detected early in visual processing, rather than on regions. Consistent with this proposal, influences from object recognition on figure-ground organization were previously observed in both pictures and stereograms depicting regions of different luminance, but not in randomdot stereograms, where edges arise late in processing (Peterson & Gibson, 1993). In the present experiments, we examined whether or not two other types of contours—outlines and subjective contours—enable object recognition influences on figure-ground organization. For both types of contours we observed a pattern of effects similar to that originally obtained with luminance edges. The results of these experiments are valuable for distinguishing between alternative views of the mechanisms mediating object recognition influences on figure-ground organization. In addition, in both Experiments 1 and 2, fixated regions were seen as figure longer than nonfixated regions, suggesting that fixation location must be included among the variables relevant to figure-ground organization.     

Measuring and predicting the effects of alcohol consumption on contrast sensitivity for stationary and moving gratings

Contrast sensitivity was measured for 12 healthy young males while sober, after ingestion of an alcohol placebo, and after ingestion of alcohol (95% grain alcohol; mean estimated blood alcohol level = .088%). Observations were made for both stationary gratings and gratings that traveled through a circular path and required pursuit eye movements. The significant alcohol-related reduction in contrast sensitivity was 2.6 times greater for moving (.29-log-unit reduction) than for stationary gratings (.11-log-unit reduction). The loss in contrast sensitivity for the moving gratings of high spatial frequency (12 cpd) was particularly severe (.37 log unit). Estimated blood alcohol level was correlated with the loss in contrast sensitivity for moving gratings (r = .61), but not with the loss for stationary gratings. Estimated blood alcohol level was strongly correlated with the difference between the loss in contrast sensitivity to moving and stationary gratings (r = .75). These results are consistent with reports that alcohol consumption degrades the ability to make pursuit eye movements. Subjects’ perceived intoxication level was not a reliable predictor of any index of visual performance.     

The effect of gap depth on the perception of whether a gap is crossable

Four experiments were performed in order to examine the effect of gap depth on human observers’ perception of whether or not a gap is crossable. Experiments 1 and 2 showed that as the gap’s depth increased, observers tended to increasingly underestimate the maximum width of a gap they could step across. Experiments 3 and 4 clarified this finding: The observed covariation of perceived gap crossability and gap depth depended on the observer’s direction of gaze, rather than on the physical depth of the gap. The optical relations to which observers might be attending are discussed, as well as the possibility that cognitive-affective processes might have contributed to observers’ underestimation of their actual capabilities.     

Children's Decisions About Substance Use: An Application and Extension of the Theory of Reasoned Action1

This research examines the applicability of Fishbein and Ajzen's (1975) theory of reasoned action (TRA) to intentions to use cigarettes and alcohol among 5th- and 6th-grade students. It also addresses the question of unidimensionality of outcome beliefs and referent norms. Results suggest that the TRA model describes children's decision making well, although the ability of income and race to add to prediction, net of the effects of attitude and perceived norm, are contrary to the theory's prediction. In addition, we find support for multidimensional components of both attitude and norm for both behaviors.     

Helping Unrelated Strangers: Physical and Psychological Reactions to the Bone Marrow Donation Process Among Anonymous Donors1

The development of models that predict outcomes of voluntary action is important for practitioners who manage large groups of volunteers. In accordance with this goal, a path model was generated linking predonation characteristics of volunteer marrow donors to postdonation physical and psychological reactions. Questionnaire data were collected from 343 individuals registered to donate marrow to unrelated strangers at 3 time points: shortly predonation, shortly postdonation, and 1-year post- donation. Although donors had generally positive reactions to donation, a substantial minority reported ambivalence about donating, physical difficulty with donation, and negative psychological reactions postdonation. In addition, our data suggest that predonation ambivalence is a central predictor of postdonation reactions, even after other donor characteristics are taken into account. These results have practical implications for the recruitment of volunteers, and suggest important variables to be considered in evaluating potential bone marrow donors.     

Sensitizing Medical Residents to Fantasies and Alignments in the Family: Mastering Psychosocial Skills in the Medical Encounter

In this paper, it is proposed that a) psychosocial medicine is best taught in a setting that provides technical and emotional support, while seizing for teaching only those moments when the learner is most receptive; and b) that the setting should avoid the development of a separate psychosocial skills curriculum, but should take the student where he or she is and integrate the psychosocial skills into his or her everyday biomedical practice. The paper gives specific case examples in which family based psychosocial issues were preeminent in the clinical problem-solving medical residents faced.     

Values and Valences: Variables Relating to the Attractiveness and Choice of Food in Different Contexts1

This study investigated relations between values and the attractiveness and choice of food in different contexts for a sample of 464 participants who completed a mail survey distributed in 12 supermarkets in metropolitan Adelaide, South Australia. Participants responded to 5 hypothetical scenarios describing situations, each of which presented 2 alternatives relating to the presentation or consumption of different foods. Participants also completed the Schwartz Value Survey (Schwartz, 1992). Results showed that measures of the attractiveness (or valence) of each alternative and choice of alternative were related to specified value types for some scenarios, depending on context and structural relations among the value types engaged by each alternative. Results also implied that choice of alternative was mediated by the valences.