Properties of spatial representations: Data from sighted and blind subjects

Five questions concerning the properties of spatial representations are explored. (1) How accurately does a spatial representation correspond to the true scene? (2) If inaccurate, how does it differ? (3) Are representations of a familiar scene more accurate than those of an unfamiliar one? (4) Do representations of a scene currently in view differ from those retained in memory? (5) Do the representations of the blind have properties comparable to those-of the sighted? Seven sighted and 7 highly mobile blind subjects, all familiar with a room, and 6 sighted subjects unfamiliar with it, were asked to estimate the absolute distances between 10 salient objects in the room. The 14 familiar subjects made their estimates twice: while they were in the room, and while they were remote from it. Regression analyses showed that the estimates of all subjects had strong metric properties, being linearly related to true distance, with a true zero point; and multidimensional scaling showed that all subjects produced distance estimates that could be scaled in two dimensions to closely match the actual locations of the objects. Familiarity had no effect. The effect of location of testing was the same for both the sighted and the blind: all subjects displayed better spatial knowledge when tested in the room; and all subjects underestimated true distance substantially when tested out of the room. The results showed no qualitative differences as a function of blindness, at least for these highly skilled blind travelers.     

The rationing of health care: A doctor's dilemma

Physicians are currently presented with very difficult ethical issues regarding who receives what level of medical care and for how long. A meaningful response to these perplexing issues necessitates a collaboration of doctors with others steeped in religious and ethical traditions. This paper addresses the complicated issue of the rationing of health care, and this issue is then addressed by responses from representatives of the religious community. This symposium took place at the New York Hospital—Cornell Medical Center in March 1991.The Rev. Curtis W. Hart, M.Div. is Director of Pastoral Care and Education at the New York Hospital—Cornell Medical Center.The Rev. Paul Conner, O.P., is Associate Professor and Director of the Master's Program in Public Health Care Ethics at New York Medical College. Larry Rasmussen, Th.D., is Reinhold Niebuhr Professor of Social Ethics at Union Theological Seminary in New York. Dr. Harlan J. Wechsler is Rabbi of Congregation Or Zarua and Visiting Professor of Philosophy at Jewish Theological Seminary in New York.     

Concurrent Use of Cigarettes,Alcohol, and Coffee1

The interrelationships between cigarette, alcohol, and coffee use were examined in 307 U.S. army trainees and 304 U.S. enlisted army personnel. Usage patterns indicated distinct gender differences in this occupational setting. Among women, cigarette use and alcohol consumption were positively correlated; whereas for men, cigarette and coffee use were positively related. For both males and females, alcohol and coffee use were only weakly correlated. As demonstrated in other studies, nonsmokers showed a consistent pattern of abstention from coffee and alcohol or moderate alcohol use.     

The myth of science education

It is argued that the manner in which we teach science in the high schools represents an outdated positivistic conception of science. The standard presentation of a year of each of chemistry, biology and physics should be replaced by an integrated science plus history, philosophy, and sociology of science which would take a total of three years to complete. A proper appreciation for the true nature of science is essential to the continued health of the scientific enterprise.     

Affective influences on individual and group judgments

Do emotional states influence the social judgments made by groups and individuals? Based on affect-cognition theories and research on group judgmental shifts, we predicted that group discussion will enhance positive mood effects on judgments, but inhibit affectively-based distortions in dysphoric moods. Positive, neutral and negative moods were induced using audiovisual presentations. Individual and group consensus judgments of nine person categories on three judgmental dimensions (evaluation, competence and self-confidence) were obtained in two experimental sessions separated by a two-week interval. Results showed that individuals made more positive judgments when happy, and more negative judgments when sad than did controls. Group discussion resulted in a further polarization of positive judgments, and the attenuation of negative judgments. The findings are interpreted as evidence for the important role affect plays in mediating both individual cognitive processes and interactive social behaviours. The implications of the results for contemporary affect-cognition theories and models of group behaviour are considered.     

Cholinergic-dopaminergic interactions in cognitive performance

Both acetylcholinergic (ACh) and dopaminergic (DA) systems have been found to be crucial for the maintenance of accurate cognitive performance. In a series of studies examining those aspects of cognitive function revealed by the radial-arm maze, we have found that these two neurotransmitter systems interact in a complex fashion. Choice accuracy deficits in the radial-arm maze can be induced by blockade of either muscarinic- or nicotinic-ACh receptors. The choice accuracy deficit induced by blockade of muscarinic receptors with scopolamine can be reversed by the DA receptor blocker, haloperidol. The specific DA D1 blocker SCH 23390 also has this effect, whereas the specific D2 blocker raclopride does not, implying that it is D1 blockade that is critical for reversing the scopolamine effect. On the other hand, the choice accuracy deficit induced by nicotinic blockade with mecamylamine is potentiated by haloperidol. This effect is also seen with the D2 antagonist raclopride, but not with the D1 antagonist SCH 23390, implying that it is the D2 receptor which is important for the potentiation of the mecamylamine effect. The relevance of the D2 receptor for nicotinic actions on cognitive function is emphasized by the finding that the selective D2 agonist LY 171555 reverses the choice accuracy deficit caused by mecamylamine. Nicotinic and muscarinic blockade are synergistic in the deficit they produce. Antagonist doses subthreshold when given alone produce a pronounced impairment when given together. This latter deficit can be reversed by the D2 agonist LY 171555. These studies have outlined the complex nature of ACh-DA interactions with regard to cognitive function. Possible neural circuits for these interactions are discussed. The effectiveness of these selective DA treatments in reversing cognitive deficits due to ACh underactivation suggests a novel approach to treating cognitive dysfunction in syndromes such as Alzheimer's disease.     

Failure to detect changes to attended objects in motion pictures

Our intuition that we richly represent the visual details of our environment is illusory. When viewing a scene, we seem to use detailed representations of object properties and interobject relations to achieve a sense of continuity across views. Yet, several recent studies show that human observers fail to detect changes to objects and object properties when localized retinal information signaling a change is masked or eliminated (e.g., by eye movements). However, these studies changed arbitrarily chosen objects which may have been outside the focus of attention. We draw on previous research showing the importance of spatiotemporal information for tracking objects by creating short motion pictures in which objects in both arbitrary locations and the very center of attention were changed. Adult observers failed to notice changes in both cases, even when the sole actor in a scene transformed into another person across an instantaneous change in camera angle (or “cut”).     

Internalizing and externalizing characteristics of sexually and/or physically abused children

This study evaluates the behavioral consequences of childhood abuse (sexual, physical, or both), with particular focus on prevalence of posttraumatic stress disorder (PTSD). Three abuse type groups and nonabused controls were contrasted on behavioral rating scales and on structured psychiatric interview data. The participants (109 abused children and 16 normal control children) were recruited from Arkansas Children’s Hospital and local agencies for abused children. As expected, proportionately more females than males were sexually abused. Overall, males were rated as more disturbed than females. Type of abuse did not consistently influence behavioral ratings. Externalizing scores were significantly higher than internalizing scores in all abused groups. PTSD was diagnosed in 50% of the abused children, with a higher rate for boys who had been sexually abused as opposed to physically abused only (58% versus 13%). The most frequent comorbid condition with PTSD was Separation Anxiety. Sexually abused boys were hospitalized for psychiatric treatment at a higher rate than were other abused children.     

On the dynamics of dying

This study is concerned with dynamic processes that underly the rapid, degenerative changes associated with the “dying” stage of the multicellular organism's life cycle. The interaction between negative and positive feedback cycles is discussed: negative feedback cycles underly the superstability characteristic of health and illness. When negative feedback cycles fade in the dying phase of life, positive feedback cycles, previously held in check by the negative feedback cycles to which they had been coupled, rise explosively, driving physiologic variables from their normal values towards extremes. This results in the rapid downturn that we associate with dying—an accelerating disintegration terminating in death. A medical case history is analyzed.