Is stimulus structure in the Mind's eye? An examination of dimensional structure in iconic memory

Three experiments examined integral and separable dimensions as attentional selective cues from iconic memory. Sperling's partial-report task was employed with physically separable and physically integral stimuli. Stimulus displays were varied in terms of the redundancy of the irrelevant non-cued dimensions—i.e. control, correlated, and orthogonal conditions within Garner's (1974a) framework—and selective readout performance was measured. The results demonstrate that, in initial processing, physically separable dimensions (e.g., circle size vs. angle of radial line) can be selectively attended to as independent dimensions, but physically integral dimensions (e.g., size vs. brightness and height vs. width) can only be represented as wholistic integral objects. Implications of these findings for current models of feature integration and perceptual development are discussed.     

Old-age deficits in the sense of smell as gauged by thresholds, magnitude matching, and odor identification

Twenty elderly subjects (70-90 years old) and 20 young control subjects (18-24 years old) underwent three kinds of olfactory testing: absolute thresholds to three odorants (d-limonene, iso-amyl butyrate, benzaldehyde), magnitude matching of these odorants to salt tastes, and odor identification of 30 common substances. For all three odorants elderly subjects' mean threshold significantly exceeded that of the young by about ninefold for d-limonene, about threefold for benzaldehyde, and about twofold for iso-amyl butyrate. These threshold differences predict approximate concentration differences necessary to arouse the same estimated odor strength above the threshold for the elderly and the young. Young subjects also scored better than the elderly in odor identification, even when subjects were given four alternatives from which to select the correct label. Unimpaired olfactory functioning is uncommon in the elderly; correlational tests show that as a group the young have better olfactory ability and show more interindividual uniformity.     

Equality and differentiation of time spent in paid work in two-income families

The cumulative data from the National Opinion Research Center General Social Survey for 1972–1978 are used to test a model of allocation of time to work in families in which both spouses are employed. Using number of hours worked during the previous week as a dependent variable, we find that for white respondents, women work fewer hours than men; fathers of preteenaged children work more hours than other men, while mothers of preteens work fewer hours than other women; both men and women work more hours when they have higher prestige occupations; and both work more hours if their status (measured by education and prestige) is equal to or higher than their spouses'. Number of hours reported for spouse in the previous week is positively related to number of hours reported by respondent. The model suggests that within two-income families equality of occupational status is associated with equality of occupational involvement, while inequality of occupational status is associated with lower occupational involvement of the spouse with lower status.     

Surface tilt (the direction of slant): A neglected psychophysical variable

Surface slant (the angle between the line of sight and the surface normal) is an important psychophysical variable. However, slant angle captures only one of the two degrees of freedom of surface orientation, the other being thedirection of slant. Slant direction, measured in the image plane, coincides with the direction of the gradient of distance from viewer to surface and, equivalently, with the direction the surface normal would point if projected onto the image plane. Since slant direction may be quantified by the tilt of the projected normal (which ranges over 360 deg in the frontal plane), it is referred to here assurface tilt. (Note that slant angle is measured perpendicular to the image plane, whereas tilt angle is measured in the image plane.) Compared with slant angle’s popularity as a psychophysical variable, the attention paid to surface tilt seems undeservedly scant. Experiments that demonstrate a technique for measuring apparent surface tilt are reported. The experimental stimuli were oblique crosses and parallelograms, which suggest oriented planes in 3-D. The apparent tilt of the plane might be probed by orienting a needle in 3-D so as to appear normal, projecting the normal onto the image plane, and measuring its direction (e.g., relative to the horizontal). It is shown to be preferable, however, to merely rotate a line segment in 2-D, superimposed on the display, until it appears normal to the perceived surface. The apparent surface tilt recorded in these experiments corresponded closely to that predicted by assuming the 3-D configurations consist of equal-length lines and perpendicular intersections.     

Developing Standard Recommendations (Guidelines) for Genetic Counseling Practice: A Process of the National Society of Genetic Counselors

The National Society of Genetic Counselors (NSGC) supports the development of practice recommendations (guidelines) in the field of genetic counseling. This paper reviews the basic components of NSGC genetic counseling practice recommendations as well as the process for formal adoption of such documents, as approved by the Board of Directors of the NSGC.     

Switching points of view in spatial mental models

In six experiments, subjects read narratives describing varying spatial scenes with more than one point of view. They were probed with questions about objects located in six directions from each character's point of view. Subjects' response times were consistent with a one place-one perspective rule. They seemed to form separate mental models for separate places and to take a character's perspective when there was only one relevant character in a scene, but they seemed to take a neutral perspective when there was more than one probed point of view, rather than switch perspectives.     

Sequential dependencies in the Eriksen flanker task: A direct comparison of two competing accounts

In the conflict/control loop theory proposed by Botvinick, Braver, Barch, Carter, and Cohen (2001), conflict monitored in a trial leads to an increase in cognitive control on the subsequent trial. The critical data pattern supporting this assertion is the so-called Gratton effect—the decrease in flanker interference following incongruent trials—which was initially observed in the Eriksen flanker task. Recently, however, the validity of the idea that this pattern supports a general conflict/control mechanism has been questioned on the grounds that the Gratton effect is only observed with stimulus repetition. We present an experiment testing whether the Gratton effect reflects a stimulus-independent increase in cognitive control or stimulus-specific repetition priming. Although our results support the latter hypothesis, the priming effect is modulated by the congruency of the previous trial. We discuss a new mechanism through which monitored conflict is used to exert executive control by modulating stimulus-response associations.