Disruption of a temporal discrimination under response-independent shock

The responding of rats was reinforced on one key after a 1-sec auditory stimulus and on a second key after a 5-sec stimulus. With errors punished by a short timeout, all subjects achieved a high level of accuracy. A chain of responses during the stimuli mediated the performance so that when the auditory signals were omitted accuracy decreased only slightly. Response-independent aversive stimulation superimposed upon this procedure both suppressed the total amount of behavior and reduced the accuracy of the discriminative performance, the intensity of the stimulus determining the error rate. The increase in errors under these conditions may have depended in part upon differential suppression of members of the response chain, but such suppression was not necessary, since error rate increased even in its absence. Furthermore, the locus of response disruption within the chain was not consistent from day to day either for any individual animal or across animals.     

A new challenge to ethical codes: Heart transplants

Summary We have entered into a new era of medical achievement with the development of successful transplantation of human organs. The transplantation of the heart has aroused the greatest scientific interest and at the same time created serious new problems of an ethical and legal nature. It has been necessary to develop new criteria to determine the moment of death of the donor in order to ensure continued life for the recipient. The decision of the moment of death should be made by a small team of skilled physicians interested in furthering this important development, but not as emotionally involved as are the surgeons awaiting the chance to prolong their patient's life with a new heart. Available and suitable hearts will probably always be in very short supply, and the selection of recipients will therefore become critical if the procedure proves to be widely acceptable.New laws will be essential before this process can be adopted in many states and countries. The cost in terms of total resources is so large that careful evaluation of the long-term results must be undertaken after a reasonable number of patients have been operated on and observed, perhaps at the end of the second year following the first procedure. Since the cost of each operation of this type approximates that of the education of several young physicians who could care for thousands of patients during their life span, a good hard look at the potential benefits and ultimate values is in order. At this point in time it is extremely important that this type of surgery be encouraged but limited to those prepared to undertake it with maximum skill and minimal risk. At present it must be recognized as a great experiment rather than a therapeutic triumph for general application.     

COMMONALITY OF WORD LISTING,PREDICTABILITY, ORIGINALITY AND CHUNKING

Les AA. analysent les données de deux épreuves verbales (liste de mots, créativité) auxquelles ont été soumis des adolescents hindous (N = 144) et américains (N = 96). Ils constatent que : (1) les sujets hindous montrent plus de variabilité dans la tendance à donner des mots identiques (commonality) dans une liste et se caractérisent par un nombre plus élevé de “ groupes ” de mots, liés entre eux dans une même chaîne de pensée; (2) les filies donnent plus de mots identiques que les garçons, mais seulement dans le groupe américain; (3) il existe une relation faible, mais de sens contraire, entre la prédictibilité et le groupement des mots dans les deux groupes linguistiques. La discussion est centrée sur la pertinence des ressemblances plutôt que des différences en matière de comparaisons interculturelles; les similitudes verbales pourraient refléter chez les sujets américains L'orientation vers le groupe des pairs et il est possible de donner d'autres explications à L'absence de Jiaison entre les similitudes verbales, la prédictibilité, I'originalité et la tendance à répondre par groupes de mots.