Eye tracking provides no evidence that young infants understand path obstruction

In two experiments with 47 4-month-olds, we investigated attention to key aspects of events in which an object moved along a partly occluded path that contained an obstruction. Infants were familiarized with a ball rolling behind an occluder to be revealed resting on an end wall, and on test trials an obstruction wall was placed in the ball's path. In Experiment 1, we did not find longer looking when the object appeared in an impossible location beyond the obstruction, and infants did not selectively fixate the object in this location. In Experiment 2, after rolling one or two balls, we measured infants' fixations of a two-object outcome with one ball in a novel but possible resting position and the other in a familiar but impossible location beyond the obstruction. Infants looked longer at the ball in the possible but novel location, likely reflecting a looking preference for location novelty. Thus we obtained no evidence that infants reasoned about obstruction and identified a violation on that basis.     

Tapping into the interplay of lexical and number knowledge using fast mapping: A longitudinal eye-tracking study with two-year-olds

Language skills and mathematical competencies are argued to influence each other during development. While a relation between the development of vocabulary size and mathematical skills is already documented in the literature, this study further examines how children’s ability to map a novel word to an unknown object as well as their ability to retain this word from memory may be related to their knowledge of number words. Twenty-five children were tested longitudinally (at 30 and at 36 months of age) using an eye-tracking-based fast mapping task, the Give-a-Number task, and standardized measures of vocabulary. The results reveal that children’s ability to create and retain a mental representation of a novel word was related to number knowledge at 30 months, but not at 36 months while vocabulary size correlated with number knowledge only at 36 months. These results show that even specific mapping processes are initially related to the acquisition of number words and they speak for a parallelism between the development of lexical and number-concept knowledge despite their semantic and syntactic differences.     

Sex differences in the perceived causal structure of date rape: A preliminary report

The present study examines the perceived causes of date rape by the use of network analysis. The 142 subjects in the study were presented with grids containing 9 causes listed by row and column. They were asked to indicate if they belived there was a causal link between each of the 72 causal pairings. The resulting network placed emphasis on male and female drunkenness, norms of dating, and society's attitude to date rape as distal causes of date rape. Misunderstanding of behavior by men, male attitude that date rape is unimportant, and need by males for dominance were seen as proximal causes. Further networks for each sex were constructed: these showed clear division of opinion on the causes of date rape. © 1995 Wiley-Liss, Inc.     

Effects of neonatal treatment with 1-(2,5-dimethoxy-4-lodophenyl)-2 aminopropane HCI (DOI) and ritanserin on agonistic behavior in adult male and female rats

The role played by the neonatal 5-hydroxytryptamine (5HT) system in the organization and sexual differentiation of adult agonistic behavior was investigated in rats. Focus was on the 5HT2 receptor subtype, which has been demonstrated to be involved in agonism control in the adult. 5HT2 activity was experimentally manipulated by administration of a specific agonist [1-(2, 5-dimethoxy-4-iodophenyl)-2-aminopropane HCl (DOI)] or antagonist (ritanserin) during the second week of life, when serotonin is known to concur to anatomical and behavioral sexual differentiation. Interactions between early 5HT2 activity, genetic sex, and neonatal circulating testosterone (T) were studied by administering the ligands to males, females, and androgenized females. At adulthood, the animals were tested for both aspects of agonism, i. e., aggression and defense, in a 20-min confrontation with an unfamiliar conspecific of the same sex, age, body weight, and social experience. Neonatal administration of the 5HT2 antagonist ritanserin increased aggression independently of sex; it also increased defense, but this effect was confined to males. The agonist DOI had no effect on aggression, but enhanced defense in males and androgenized females, with an effect which depended therefore more on neonatal T than genetic sex. Females appeared in general less sensitive to neonatal 5HT2 manipulation than both androgenized females and males; this suggests that neonatal T is crucial for experimental modifications of neonatal 5HT2 activity to have any consistent effect on adult agonistic behavior. On the other hand, effects observed in males and androgenized females were dependent on the behavior considered and the drug administered. This was especially evident for defense, enhanced by ritanserin in males only, and in both males and androgenized females by DOI. Neonatal 5HT2 activity seems therefore to play a role in the modulation of adult agonistic behaviors, which depends on the behavior considered and is under multiple control of genetic sex and hormonal neonatal substrate. © 1994 Wiley-Liss, Inc.     

Sex differences in maternal behaviors of immature rats: The role of emotionality

Immature rats are able to give maternal care to pups and may increase their inclusive fitness by helping newborn siblings. Immature males are generally reported to be more maternal than females. In this research we studied sex differences and the extent to which they may be due to a different emotional response to novelty. We studied maternal response in two groups of immature rats of both sexes: in the naive group, juveniles aged from 18 to 30 days were given one test and showed clear-cut sex differences. The experience group was submitted to repeated tests from 18 to 30 days of age, thus eliminating the effects of novelty: as a result, all differences between sexes disappeared. A second experiment was designed in 24-day-old females to differentiate the effects of repeated handling and exposure to the test situation from that of repeated exposure to pups; moreover, the effects of an anxiety-reducing drug (diazepam) were studied. Exposure to pups is particularly efficient in facilitating maternal response. Diazepam injection was also effective, but its control showed that the injection per se was responsible for the effect. In conclusion, our results stress the importance of response to novelty and suggest that sex differences in maternal behavior of immature rats may be modulated by different emotional responses by males and females. In fact, emotionality competes with, and may exert an inhibitory effect on, the expression of a vast array of behaviors. © 1994 Wiley-Liss, Inc.     

Variation in aggressive behavior and anatomo-physiological correlates generated by crowding without physical contact in the house mouse

Behavioral, physiological (i.e., endocrine), and anatomical consequences of crowding in mice were studied in a situation where animals were in auditory, visual, olfactory, and tactile contact but restrained from full physical interactions, to prevent overt aggression. Males that cohabited with females undisturbed by neighboring conspecifics showed greater propensity to attack same-sex intruders and had higher plasma testosterone levels than did their “crowded” counterparts, that is, males cohabiting with females and housed adjacent to other male/female pairs. In this respect, the latter animals resembled submissive males. However, a significant increase in weight of androgen-dependent target organs (i.e., seminal vesicles and preputial glands) was found in crowded males. These data indicate that despite the observed inhibition of social aggression these males are not physiologically comparable (homologous) to male mice that experienced defeat and the stress of submission during fighting. The intriguing possibility that different conversion pathway of testosterone are accelerated, as a result of social communication, in males living in these two environments and the behavioral implications of these possibilities are discussed. Finally, the parental behavior of crowded animals, although not freely interacting with each other, was disrupted, causing a marked decrease in reproductive success. In this situation a high incidence of infanticide of their offspring by both parents was observed, whereas this behavior was virtually absent in non-crowded male/female pairs.     

Triggering Creative Self-Efficacy to Increase Employee Innovation Behavior in the Hospitality Workplace

This study investigated how creative personality, psychological empowerment, and job stress affect creative self-efficacy and innovative behavior in hospitality employees. A hypothesized moderating role of knowledge-sharing role in the relationship between creative self-efficacy and innovative behavior was also tested. Three hundred and thirty-nine employees and 89 supervisors employed by International Tourist Hotels in Taiwan participated in the study. A structural equation modeling analysis indicated that creative self-efficacy significantly mediates the effects of creative personality and psychological empowerment on innovative behavior in the hospitality industry. The positive effect of creative self-efficacy on innovative behavior was larger in high knowledge-sharing work environments than in low knowledge-sharing work environments. Theoretical and practical implications are further discussed.     

Aggressive behavior in the free-ranging rhesus monkeys of kathmandu,nepal

We present a composite sample of the aggressive behavior of free-ranging rhesus monkeys (Macaca mulatta), recorded at two temples in Kathmandu, Nepal. We analyze the total number and the rate per monkey of threats, chases, attacks, fights, and aggressive acts directed at other species (principally humans), in order to elucidate social dynamics of the troop as a whole. Our 1,506 hours of observation were divided among the four seasons; between a.m. and p.m.; and among a temple yard, two parklands, and a forested garden. We found seasonal patterns to be the most important correlates of aggressive behavior. Habitat was a modulating influence, and time of day was the least important factor. Rates of aggression were generally higher per male monkey than per female. In terms of total aggression recorded, however, females instigated significantly more than males, both in encounters between monkeys and in aggression against other species. This finding is consistent with the females' greater numbers in the troop and with their lifelong membership in the troop. Analysis of behavior by social groups, rather than by individual rates, points up the iomportance of adult females and their social stability in troop behavior.     

Effects of medial preoptic hypothalamus anterior lesions on three kinds of behavior in the rat: Intermale aggressive,male-sexual,and mouse-killing behavior

Large lesions in the medial preoptic area-anterior hypothalamus (MPOA-AH) of adult male S3 rats reduce both intermale aggressive behavior and male sexual behavior considerably, but mouse-killing behavior is not impaired. Daily treatment with high doses of testosterone propionate for 21 days does not restore these behavioral effects. Smaller lesions in the same area affect male sexual and intermale aggressive behavior differently; in the frontal part of the MPOA-AH they affect aggressive behavior, while in a more caudal part they affect sexual behavior. Indications were found that lesions in specific parts of the stria terminalis and the medial forebrain bundle inhibit aggressive and sexual behavior.     

Intersexual aggression and male sexual activity in captive rhesus macaques

Rape has been posited to be an outgrowth of male reproductive strategies. Forced copulations may have evolved as a consequence of the low parental investment made by males in producing and raising offspring. We designed a laboratory experiment which paired rhesus macaque males with females in order to assess the influence of intersexual aggression on male sexual activity. Younger and older adult males had comparable levels of sexual behavior, but younger males were more aggressive towards females than were older males. In addition, females threatened younger males more than older males. Male attacks on females did not result in sexual intercourse. On the contrary, a negative correlation existed between male aggression towards females and male success at achieving intromissions. Female aggression towards males appeared to be an effective tactic which reduced the chances of sexual intercourse. We conclude that intersexual aggression acts either as a mechanism of dominance assertion or as a means to increase spatial distance between individuals. These data do not support the idea that rape in humans has an evolutionary foundation derived from male reproductive strategies.