Biomedical subjects

J M Beer

Publications and source records attributed to J M Beer.

4 recordsLinked to original sources

PubMed2000

The influence of rearing order on personality development within two adoption cohorts.

There is an extensive literature on the relationship between birth order and psychological traits, but no previous study has investigated the influence of ordinal position on personality development within adoptive siblings. Such a design is important because it effectively separates the effects of biological birth order and rearing order. Here we report data from two adoption cohorts in which subjects were biological first-borns reared in various ordinal positions. Data were analyzed with reference to Sulloway's (1996) evolutionarily based sibling rivalry theory of birth order effects. Between- and within-family analyses indicated that rearing order's influence on personality was very weak. The only clear difference was for conscientiousness, on which first-reared siblings scored higher. We draw possible implications for Sulloway's theory and speculate upon an alternative, prenatal biological process that may produce birth order differences.

Adolescent↗

PubMed1998

Genetic and environmental influences on MMPI factor scales: joint model fitting to twin and adoption data.

In general, the shared family environment appears to play a negligible role in determining individual differences in personality and interests. Nevertheless, scattered reports of significant shared environmental influence on such variables appear in the literature. Using data from the Texas Adoption Project (TAP), the current study attempted to replicate twin study findings of significant shared environmental variance on four of nine Minnesota Multiphasic Personality Inventory (MMPI) factor scales (Rose, 1988). Conventional behavioral genetic analyses of the adoption data agreed in affirming a significant shared environmental influence on individual differences in Religious Orthodoxy only. Subsequent simultaneous modeling of Rose's twin data and TAP adoption data resulted in three scales (Extraversion, Inadequacy, and Religious Orthodoxy) showing significant shared environmental influence. Again, effects were most substantial for Religious Orthodoxy, where the shared environment accounted for nearly 50% of the variance. It is argued that assortative mating cannot explain this finding.

Adolescent↗

PubMed1998

Effects of gaze angle and extraretinal eye movement information on visual locomotion control.

This study tested effects of gaze--movement angle and extraretinal eye movement information on performance in a locomotion control task. Subjects hovered in a virtual scene to maintain position against optically simulated gusts. Gaze angle was manipulated by varying the simulated camera pitch orientation. Availability of extraretinal information was manipulated via simulated-pursuit fixation. In Experiment 1, subjects performed better when the camera faced a location on the ground than when it pointed toward the horizon. Experiment 2 tested whether this gain was influenced by availability of appropriate eye movements. Subjects performed slightly better when the camera pointed at nearby than at distant terrain, both in displays that did and in displays that did not simulate pursuit fixation. This suggested that subjects could perform the task using geometric image transformations, with or without appropriate eye movements. Experiment 3 tested more rigorously the relative importance of gaze angle and extraretinal information over a greater range of camera orientations; although subjects could use image transformations alone to control position adequately with a distant point of regard, they required eye movements for optimal performance when viewing nearby terrain.

Computer Simulation↗

PubMed1993

Perceiving scene layout through an aperture during visually simulated self-motion.

This study tested scene perception during depicted self-movement. In Experiment 1, viewers reproduced angular scene configurations, revealed over time by camera motions in depth. Viewers used visible flow to update off-screen locations of landmarks that had been drawn from view and thereby perceived scenes in depth beyond the display's boundaries. Experiments 2 and 3 tested whether offscreen space is perceived as a function of depicted velocity and time and whether information from prior views is used. Viewers predicted when lateral movement would reveal a peripheral landmark whose location was shown in a prior panoramic view. Accurate responses, observed under certain conditions, would result if viewers perceived space according to S = integral of V dt (D. Algom & L. Cohen-Raz, 1984, 1987; R. Jagacinski, W. Johnson, & R. Miller, 1983). When required to picture wide spans in space yet to emerge, however, viewers responded as if these spans were compressed. The theoretical implications of the ability to retrieve, transform, and apply information after a discontinuous transition from a prior view are discussed.

Adult↗