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.     

Sex roles, gender, and fear

Male and female college students classified as masculine, feminine, androgynous, or undifferentiated on the Bem (1974) Sex Role Inventory (N = 199) were given the Wolpe (1969) Fear Inventory. Significant differences in average fear scores were seen between men and women and between the four sex-role categories, with sex role and gender contributing equally to the variability. The argument is raised here that excessive fearfulness or fearlessness might be as much a product of sex-role conditioning as a product of gender.     

Discriminated interresponse times: role of autoshaped responses.

When discriminated interresponse-time (IRT) procedures have been used to assess preference relations among temporally extended operants, deviations from matching have been obtained. Using a yoked-control procedure, the present study found that key pecking in a discriminated IRT procedure has two sources of strength--that arising from the response-reinforcer contingency that is explicitly arranged, and that arising from a stimulus-reinforcer contingency that is a by-product of the explicitly arranged contingency. The key pecking of all lead birds, and that of 3 of the 4 birds exposed to a yoked autoshaping procedure, was controlled by the keylight that signaled the lead birds' criterion IRTs. Because stimulus control of key pecking by the keylight, whether autoshaped or discriminative, fosters deviations from matching, the discriminated IRT procedure does not provide an appropriate basis for conclusions about preference relations among IRTs.     

Resolving discrepant results of the Wheatstone Experiment

Summary Soon after Wheatstone published his results obtained with the twelve earliest stereograms. Brewster disputed the result obtained with one of them. This stereogram consisted of a thick vertical line presented to one eye and a thin vertical and thick inclined line to the other. Wheatstone reported seeing depth with this figure but Brewster did not. We conducted three experiments to explore the possible reason for the disagreement. Experiment 1 indicated that the stereogram produces a variety of perceptions including the depth as reported by Wheatstone and the rivalry as reported by Brewster. Experiment 2 showed that Brewster's procedure of keeping the eyes fixed while viewing the stereogram reduces the proportion of subjects reporting depth. In Experiment 3, the top half and the bottom half of the stereogram were presented in different trials. The top of the stereogram that contains no conflicting cues produced reliable depth, but the bottom that does, did not. It is concluded that the difference in the procedures they used and the nature of the stimulus were responsible for the conflicting results.     

Do alcoholic Korsakoff's syndrome patients acquire affective reactions?

In this study we report two experiments that investigate the acquisition of affective reactions. In Experiment 1, unfamiliar melodies were played to Korsakoff's syndrome patients and alcoholic and nonalcoholic control subjects who were matched with them according to age and education. Following a retention interval of 5 min, subjects received a preference test on old and new melodies. Korsakoff's syndrome patients showed the same increase in preference for old melodies as a consequence of prior exposures as control subjects did, but their recognition of melodies was significantly impaired in comparison with controls. In Experiment 2, the same subjects saw photographs of two men. Fictional biographical information depicted one as a "good guy" and the other as a "bad guy." After a retention interval of approximately 20 days, Korsakoffs recalled virtually none of the biographical information; however, 78% preferred the good guy, and impression ratings were less favorable for the bad guy. Korsakoff patients developed preferences and impressions even though they did not have voluntary access to the information on which the preferences were based. However, their impression ratings were less extreme than those of controls. The pattern of results of the two studies is discussed in terms of Johnson's (1983) MEM model of memory.     

Application of the method of fixed set to the size-weight illusion

Summary The method of fixed set (Uznadze, 1966) was applied to the size-weight illusion. After the repeated lifting of a small, heavy stimulus and a large, light one with both hands simultaneously, the size-weight illusion diminished. It increased after lifting a small, light stimulus and a large, heavy one. These changes in perception were explained as contrast effects caused by the sets which were fixed during the preceding lifts. The same method was applied to the weight-size illusion and the contrast effect was observed in some cases. The results of the application of the fixed-set method to the size-weight illusion and to the visual size perception were compared. All the results showed analogous patterns of conflicting states between the temporarily fixed set and the set that the subject prepares naturally for perception, such as the size-weight illusion. By way of conclusion, the size-weight illusion was assumed to be a kind of contrast effect in the light of Uznadze's theory of set.     

Alternation behavior, spatial discrimination, and reversal disturbances following 6-hydroxydopamine lesions in the nucleus accumbens of the rat

The effects of dopaminergic depletion of the nucleus accumbens was tested in various behavioral tasks such as alternation, spatial discrimination, and reversal learning, and in an extinction paradigm in a T maze. Animals with lesions showed impairment of spontaneous alternation behavior, disturbances in the acquisition of spatial discrimination, and great difficulty in reversing previously learned habits. In the extinction phase, experimental animals are unable to adjust their behavior, and continue to choose the previously reinforced arm of the T maze. It is suggested that the nucleus accumbens plays an important role in the transition of motivation into action, and that dopamine has a facilitatory influence on the mediation of these processes.     

Little oscillation of daily food intake in mousekiller rats as opposed to nonkiller rats before any confrontation with mice

During 46 consecutive days the daily food intake and weight were recorded in 16 male Wistar rats. On Days 31-45 one mouse was presented each rat daily. Before any experience with mice (Days 0-27) the mousekiller rats, compared with the nonkiller rats, regulated their individual food intake more closely to their homeostatic equilibria, corrected for the linear trend. This result indicates a functional difference in food intake regulation between mousekiller rats and nonkiller rats prior to any experience with mice. However, no difference in the mean food intake was found between the mousekiller and the nonkiller rats.