The effects of social motives on behavior in social dilemmas in two cultures

Subjects in Santa Barbara, California, and Groningen, The Netherlands, participated in a seven-person social dilemma game, presented in terms of a conservation of resources problem. Prior to their decision making in the social dilemma game, subject's social motive (altruistic, cooperative, individualistic, competitive) was assessed by means of two different classification procedures. On the basis of previous research findings American subjects were expected to display relatively more competitive social motives, and Dutch subjects relatively more cooperative ones. However, no indications of crosscultural differences were found neither with regard to the distribution of social motives nor with regard to the amount of resources taken for self in the social dilemma game. In both locations, competitive subjects took most resources for self, individualistic subjects took next most, cooperative subjects took less than individualists, and altruistic subjects took the least. In addition to predictive validity, indices of the convergent validity of two social motive assessment procedures were described.     

The effects of sound duration on newborns' head orientation

Two experiments assessed the importance of sound duration for eliciting head orientation responses from newborn infants. In Experiment 1, thirty infants turned with equal frequency toward 20-s continuous rattle sounds and 20-s trains of rattle segments. The duration of the rattle segments--14 and 100 ms (2/s), or 500 ms (1/s)--did not influence the likelihood of turning. Response latencies and durations proved quite similar for all stimuli. In Experiment 2, twenty-four infants heard continuous rattle sounds of four different durations: 1, 5, 10, and 20 s. They turned reliably to all stimulus durations; furthermore, the magnitude and temporal characteristics of head orientation responses did not differ for the four stimulus durations. These results suggest that the newborn's head orientation response may reflect a motor program that is initiated by auditory input and then executed in a similar fashion regardless of further stimulation.     

Imagery, encoding specificity, and prose recall in 6-year-old children

Partial pictures depict only selected portions of prose passages. Partial pictures hypothetically aid retention by inducing young children to generate imagery for nonpictured prose. Results from two hundred eighty-eight 6-year-old children indicated that (a) partial pictures at study facilitate recall, (b) identical study and retrieval prompts facilitate recall, and (c) imagery instructions and training do not affect retention. Partial pictures apparently help children to encode information more efficiently at study, but there is no evidence that young children generate images with the aid of the partial picture cues, nor that they have a retrieval deficit for these images as suggested by M. Ruch and J. Levin.     

Patients' perceptions of treatment for kidney failure: The impact of personal experience on population predictions

Estimates of the probability of various outcomes associated with treatment for kidney failure were made by chronic dialysis patients, dialysis patients awaiting transplant, successful transplant patients, and unsuccessful transplant patients back on dialysis. The latter two groups can be considered a natural experiment testing the impact of personal experience on population predictions. Consistent with the law of small numbers and the availability heuristic, successful transplant patients gave higher estimates of the population success rate for transplantation than unsuccessful transplant patients gave.