Dynamic object perception by pigeons.

Three experiments examined pigeon discrimination of computer-generated three-dimensional (3-D) projections of cube and pyramid objects. Four pigeons were tested using a go/no-go procedure involving static and dynamically rotating presentations of these stimuli. Transfer tests with different types of rotational and featural transformations suggested the pigeons may have used a 3-D representation of the objects as their primary means of performing the discrimination. The comparative implications for object and motion perception in animals are considered.     

The scaling of postural adjustments during bimanual load-lifting in traumatic brain-injured adults

Previous postural studies of traumatic brain injury (TBI) patients have been limited to identifying deficits in static and quasi-dynamic postural control tasks such as weight shifting. In this study, we examined whether or not patients with TBI are able to scale adequately their postural adjustments during the performance of the dynamic task of bimanual load-lifting. An age matched group of healthy adults served as controls. We used the Tetrax posturography system that calculates a stability score (ST) based on fluctuations in vertical ground reaction forces, normalized for body weight. During quiet standing, the ST scores of the TBI group were significantly higher than the control group. Forward weight shift and percentage change in the vertical ground reaction forces (lift postural adjustment (LPA) and post-lift postural adjustment (PLPA) scores) linearly increased with increasing load weight in both healthy and TBI subjects. Group differences were found in the magnitude of forward weight shift but not in the relative increase of the LPA and PLPA scores during the lifting and post-lifting phases respectively. The forward weight shift of the TBI group was lower-than-normal and asymmetrical--there was significantly less forward weight shift on the more affected than on the less affected limb. In addition, a significant amplitude coupling was found between the scaling of the weight shift of the heel and forefoot of each limb. However, no coupling was found between the weight shift amplitudes of homologous parts of both limbs in the TBI group. The results showed that scaling based on prior experience was preserved in the TBI group, though some TBI subjects demonstrated absent scaling in either the more affected or less affected heel or forefoot. The differences between the normal and TBI groups in postural adjustments are not necessarily a sign of pathology; rather they may represent a deliberate choice of the central nervous system to counteract predictable disturbances.     

Ambivalence Over Emotional Expression and Psychological Weil-Being Among Rheumatoid Arthritis Patients and Their Spouses1

Associations between ambivalence over emotional expression and psychological well-being among rheumatoid arthritis patients and their spouses were investigated. Sixty-nine couples completed questionnaires assessing ambivalence over emotional expression, emotional expressiveness, psychological well-being, and strategies used in coping with arthritis. Associations between the patient's ambivalence and psychological well-being were stronger for those married to a highly ambivalent spouse, although this pattern of results was not found for spouses. Lower psychological well-being among more ambivalent spouses, and to a lesser extent patients, could be partially explained by their greater use of passive and distancing coping strategies. Results emphasize the importance of taking a dyadic approach to the study of psychological functioning among chronically ill patients and their spouses.     

Reflections on unethical experiments and the beginnings of bioethics in the United States

The author offers personal reflections on the development of research ethics in the United States, primarily during the 1960s. He explores the efforts of the pioneers in the field of human experimentation ethics to raise and discuss issues such as the value conflict between the acquisition of knowledge and respect for the autonomy of research subjects and the crucial importance of disclosure in the informed consent process.     

Gender attitudes in children

This study investigated children's gender attitudes as a function of the sex, age, and race of the child as well as a geographical SES factor. Two attitudes were measured: gender pride (attributing positive characteristics to a child of the same sex) and gender prejudice (attributing negative characteristics to a child of the other sex). Results indicated that all children tended to select children of the same sex for the positive attributes, but that both boys and girls selected boys for the negative attributes. Although all sex pride scores decreased with age, this effect was most pronounced for girls from an upper-lower-class urban environment.The write-up of this article was supported by our current National Institute of Mental Health Grant No. 1R01MH29417-01, Principal Investigator, Dr. Phyllis A. Katz.