Mouse killing in rats induced by lesions of the medial hypothalamus or medial accumbens: short-term preoperative exposure to a mouse does not suppress the killing

Rats were either exposed or not exposed to a mouse in their living cage for a 48-hr period. At the end of this time a bilateral lesion was made in the medial accumbens region or in the medial hypothalamus. When tested 2 days postoperatively, the killing frequency among rats that had been exposed to mice preoperatively was not significantly lower than that of rats that were not preoperatively exposed. The ineffectiveness of preoperative experience in suppressing the mouse killing induced by medial accumbens and medial hypothalamic lesions is similar to that found previously with dorsal-median raphe lesions and olfactory bulb lesions and is in contrast to the ease with which preoperative experience prevents mouse killing induced by septal lesions and serotonergic lesions induced by 5,7-dihydroxytryptamine.     

Regret and disappointment in taxpayer reporting decisions: An experimental study

This paper reports on experiments which test whether factors such as regret or disappointment influence taxpayer compliance decisions. Previous tests of regret and disappointment theory have been based upon the common-ratio effect in which probabilities vary while outcomes are held fixed. In contrast, our experiments involved trials in which the outcomes were allowed to vary. Previous tests had mainly found evidence of regret effects and to a lesser extent were supportive of disappointment. In contrast, we were able to reject simple theories of both regret and disappointment. A second experiment produced evidence which indicates that whether or not rejected risky alternatives are resolved has no significant influence on subjects' choices. One would expect that regret could only occur when a subject learns the outcome of a non-chosen option. Hence this result can be seen as evidence against regret theory. We shall argue that there is a possible interpretation of regret theory which is compatible with this result.     

Influence of a televised model's vocalization pattern on infants

To assess the influence of a televised model's vocalizations on the vocal patterns of infant viewers, 32 infants at 6 months of age were presented either a televised adult model repeating a novel phoneme pattern (/ba/ba/ba/ba) or a control televised presentation of adult conversation selected from typical daytime programming. Sequential analyses of infant vocalizations revealed that infants exposed to the televised model altered their vocalization pattern, as indicated by a significant increase over base line levels in their production of a patterned series of discrete vocalizations. Infants exposed to the televised conversation showned no increase in this pattern of vocalization, and none of the infants in the study produced the novel phoneme (/ba/). The results indicate that televised presentation of discrete, repeated vocalizations can have an influence on the vocalization pattern of infants. The potential role of television in infant development is discussed.     

Suppression of VMH-lesion-induced reactivity and aggressiveness in the rat by stimulation of lateral septum, but not medial septum or cingulate cortex

Animals made vicious with bilateral ventromedial hypothalamic lesions had bipolar electrodes implanted unilaterally in the lateral septum, medial septum, or cingulate cortex. Four days later, the animals' reactivity and aggressiveness were evaluated 5 min before, during, and 5 min after stimulation at 20 micronA (60 Hz, sine wave). Lateral septal stimulation suppressed reactivity and aggressiveness by almost 80% compared with pre- and poststimulation levels. Stimulation of neither the cingulate cortex nor the medial septum produced a change reliably different from that seen in unstimulated control animals. Further tests with stimulation of the lateral septum at the 20-micronA level showed that neither rewarding self-stimulation nor disruption of ongoing water drinking was produced. These results are congruent with evidence from lesion studies that the lateral septum normally acts to suppress reactivity and aggressiveness in the rat; they do not support previous suggestions that the medial septum is involved in the modulation of these behaviors.     

Affiliation of opposite-sexed strangers

This study examined the effects of a subject's sex and affiliative tendency and the other's physical attractiveness on the cross-sexual interaction of strangers. Although previous studies showed that one's interest in an opposite-sexed other is a function of the other's physical attractiveness, the actual behavior of individuals in the presence of attractive and unattractive others had not been systematically examined. Subjects were individually placed in a 5-min waiting situation with a physically attractive or unattractive target of the opposite sex who behaved in a standard way. Conversations were recorded and subsequently analyzed; subjects also provided their impressions of the targets following the waiting period. Physical attractiveness of the opposite-sexed other did not significantly influence the subject's verbal affiliative behavior, but the combined influence of a subject's sex and affiliative tendency was predictive of cross-sexual affiliation. Although physical attractiveness did not account for differences in affiliative behavior, subjects preferred attractive over unattractive targets as potential dates or marriage partners.