Bilingual exposure influences infant VOT perception

Linking the discrimination of voice onset time (VOT) in infancy with infant language background, we examine the perceptual changes of two VOT contrasts (/b/-/p/ and /p^h/-/p/) by Dutch monolingual and bilingual infants from 8 to 15 months of age. Results showed that language exposure and language dominance had a strong impact on monolingual and bilingual infant VOT perceptual patterns. In addition, perceptual turbulence was found at 8–9 months for bilingual infants, and stabilized perception was presented for all infants from 11 months onwards. We thus report a general input-driven developmental VOT perception in both monolingual and bilingual infants, with perceptual turbulence for bilinguals in the second half of the first year of life.     

The effects of food deprivation,aggression, and isolation on infanticide in the male Mongolian gerbil

Male Mongolian gerbils show an increase in infanticide and pup-cannibalism after 24-hr food deprivation, suggesting that food acquisition is a function of this activity. Dominant animals show high levels of infanticide, but subordinate animals are inhibited from this activity. An increase in infanticide is seen when males from a single sex group are isolated; this increase resembles that observed when a male is separated from his pregnant mate [Elwood, 1980]. These results suggest a mechanism whereby males are normally brought into a noninfanticidal state during cohabitation with their pregnant mates owing to subordination by the latter. In this manner males are able to utilize strange pups as food but avoid harming their own offspring.     

变量相对重要性评估的方法选择及应用

高维数据爆发的背景下,心理学研究目前急需变量相对重要性评估的有效方法。相对重要性评估的关键是选择合适的评估指标和统计推断方法。相对重要性的评估指标种类繁多,优势分析和相对权重是重点推荐的相对重要性评估指标。相对重要性的统计推断方法适用情境不同,Bootstrap抽样是推断单变量重要性和两变量重要性差异的常用方法,而贝叶斯检验是评估多变量重要性次序的新方法。线性回归模型之外,相对重要性研究已拓展到Logistic回归模型、结构方程模型、多水平模型等,但适用数据类型仍较为有限。相对重要性评估已广泛应用于心理学实证研究,但存在不恰当的指标解释和方法选择问题。为此,结合具体例子说明变量相对重要性的评估过程。     

A violation of dominance and the consumption value of gambling

We document an apparently widespread violation of dominance in the horse‐racing betting market in the UK, and use the systematic variation in the incidence of this violation to estimate the consumption value of gambling. Betting‐shop gamblers in the UK face a tax on gambling of 10%, but have the choice of paying the tax either at the time of wager or on any return on a successful bet. It can be shown, however, that the latter act is strictly dominated by another action in which tax is paid on the wager. Despite this, more than 18% of bets appear to be placed by gamblers who choose to pay tax on the return. We explore the hypothesis that this apparent violation of rationality may be explained by a component of utility which represents the consumption value of gambling, which in turn varies with the amount wagered. We then estimate this component from a dataset consisting of a record of 25,000 individual bets using probit analysis of the tax decision. Copyright © 1999 John Wiley & Sons, Ltd.     

Assessment of fighting ability or simple habituation: What causes young pigs (Sus scrofa) to stop fighting?

To determine how pigs assess their relative fighting ability, I observed paired contests between young pigs that were either of similar weight or of different weight. On the first day the incidence of fighting was high, but this was not affected by the size of the weight difference. Fights between pigs of different weight were shorter than those between pigs of similar weight. When the pigs were of different weight, the eventual winner bit more frequently and spent more time attacking than did the eventual loser. This difference was not apparent when the pigs were of similar weight. On the first day, winners and losers were equally likely to initiate fights. The incidence of fighting was lower on the second day, although this was unaffected by the weight difference. Losers were less likely to initiate fights on the second day, and fights were shorter than on the first day. However, for the time that they did fight, the losers fought as vigorously (based on the rate of biting) on the second day as on the first. Seventy-two hours of visual and olfactory contact before the fight had no effect on the incidence of fighting and minimal effect on its duration. I suggest a young pig cannot assess its chance of success prior to the first encounter but only during the course of the fight. This assessment is reduced by attacks from the opponent until it drops below a critical threshold, whereupon the pig stops fighting. As a result of a previous defeat, a pig will lower its assessment and will be less likely to fight or to initiate fights on subsequent encounters. It is this change in assessment rather than habituation alone that makes pigs less likely to fight as they become acquainted.     

Formation of leap orders in pairs of male domestic chickens

There is disagreement concerning the role or importance of social leaping, compared with pecks and threats, in the dominance relations of fowl. As an approach to this issue, the current paper reports two experiments that used aggression-inducing isolation-rearing conditions of either 8 days or 8 weeks. In 5-min tests in pairs after isolation it was found that leaping was the key aggressive response in conflicts between 14- to 15-week-old roosters. Leaps were more frequent overall and occurred earlier than did pecks. Although both dominant and subordinate birds leaped at one another to some degree, only the dominant birds had both “leap rights” and “peck rights.” The data indicated that leaping is a behavior that has an important, central role in the social organization of male domestic chickens. These laboratory results were comparable to certain archival data from classic field research.     

On the (in)stability of dominance hierarchies in the cichlid fish Oreochromis mossambicus

Dominance hierarchies were studied during 8 weeks in eight heterosexual captive groups of Oreochromis mossambicus at the onset of sexual maturity. Linearity was assessed for each group on a weekly basis based on the Landau's index (h) and on the procedure described by Appleby [Appleby MC (1983): Animal Behaviour 31:600–608]. Week-to-week stability of the hierarchical structures was measured using the Burk's stability index (b) and Spearman rank correlation coefficients for the ranks of fishes in consecutive weeks. The two measures of stability showed a high level of concordance but the Spearman rank correlations were more conservative in detecting cases of stability. Although most dominance structures were linear they were unstable from week to week. Dominant individuals were less likely to experience rank reversals than subordinates. Rank reversals were especially likely among hierarchical neighbors. Dominance hierarchies did not stabilize in the time span of this study. © 1996 Wiley-Liss, Inc.     

Investigating sexual harassment in online video games: How personality and context factors are related to toxic sexual behaviors against fellow players

Online video games are social spaces for players from around the world. They use this space to form communities, relationships, and identities. However, gaming communities are not always welcoming, and some are even perceived as being “toxic.” A prevalent issue is online sexual harassment, which is keeping many women from participating in the gaming community. Research on the factors contributing to the problem is limited, though. The present study replicates and expands previous research, using a sample of 856 online gamers. The study supports earlier findings that found hostile sexism and social dominance orientation as predictors of sexual harassment perpetration in online video games. In addition, we expanded the previous research with additional predictors: machiavellianism, psychopathy, and gamer identification predicted higher sexual harassment perpetration. Our results have implications for the gaming community's role in curtailing sexual harassment and making itself a more inclusive community.     

Aggressiveness and dominance in captive cock red grouse

A method for measuring the aggressiveness of captive cock red grouse is described. A cock's aggressiveness varied according to season, type of cage and social environment. A method for ranking the dominance order of cocks in a group is also described. Dominance ranks remained stable for up to two years. Correlations between the aggressiveness of isolated cocks and their dominance ranks when in a group were positive but weak. Aggressiveness and dominance should be clearly distinguished. Both aggressiveness and dominance were related to the size of cock's combs, and implants of testosterone increased all three. In situations where a cock's aggressiveness changed, comb size changed in the same direction. The aggressive behaviour of captive cocks shows several major parallels with that of wild cocks.     

Lexicographic order preservation and stochastic dominance

Stochastic dominance concerns conditions on outcome probabilities that are necessary and sufficient for one act to be (strictly) preferred to another according to all preference relations that share certain properties, one of which customarily is an Archimedean property sufficient to entail existence of real-valued representations. We relax this assumption to permit linear lexicographic utility of finite and known dimensionality. In some situations, levels of the lexicographic hierarchy could correspond to explicit criteria or attributes. In our model, subjective probabilities emerge as matrix premultipliers of the outcome utility vectors. We thus obtain matrix probability generalizations of the familiar cumulative probability conditions for stochastic dominance.