儿童数字估计中的心理长度

从儿童对数字属性的认识角度探讨一年级儿童在不同数字范围中采用不同表征形式的根本原因。两个实验均采用数字线估计任务,实验一测量一年级儿童在15cm数字线长度下0～100与0～1000两种范围上的数字估计;实验二测量一年级儿童对0～1000范围10cm和20cm数字线长度的估计。结果显示,无论在不同的数字范围还是在不同的数字线长度下,儿童对低端数字的估计均存在心理长度,即儿童倾向于将低端数字与固定的线段长度对应起来,且这种对应关系不随数字范围与数字线长度的变化而变化。心理长度的存在是儿童在不同数字范围和不同数字线长度中采用不同数字表征形式的根本原因,也是儿童对数概念的认识发展到等距水平时出现的一种独特特点。     

心理长度对二年级儿童数字线估计表征的影响

从心理长度的角度探讨二年级儿童在0~100和0~1000数字范围存在不同表征方式的原因。实验一要求二年级儿童完成长度均为10cm,范围分别为0~100和0~1000的数字线估计任务。实验二要求儿童对长度分别为10cm和18cm,范围均为0~1000的数字线进行估计。结果发现在两个实验中二年级儿童的估计均存在心理长度,但与以往研究的一年级儿童相比,心理长度的范围有所缩小。随着数字范围的增大或长度的减小,儿童的表征方式出现了从线性表征向对数表征的转变趋势。这些结果表明不精确的表征方式可能与心理长度策略的使用有关,心理长度在一定程度上影响了二年级儿童的估计表征方式。     

Infanticide and maternal aggression: Synchrony of male and female reproductive strategies in mice

Thirty-six percent of male mice from three strains attacked newborn pups sired by another male. No male attacked its own offspring. Females did not show differential aggression toward males likely (strangers) or unlikely (sires) to attack their pups. Both forms of aggression were unaffected by housing in rooms which did or did not contain the aggression targets. The three strains differed in strength of maternal aggression but not in the incidence of infanticide. Females showed more aggression when mated with males of the same, rather than a different, strain but no differences with intruders of the same or a different strain. Infanticide by males is best viewed as a postcopulatory, intermale-competition strategy, and maternal aggression as a counter strategy.     

A matter of style? Testing the moderating effect of driving styles on the relationship between job strain and work-related crashes of professional drivers

Different empirical studies suggest that both job strain and driving styles are significant contributors to the work-related traffic crashes suffered by professional drivers. Nevertheless, the current evidence falls considerably short when explaining why driving styles may modify (or not) the relationship between occupational stressors and professional drivers’ safety outcomes. The aim of this study was to examine whether driving styles moderate the effect of job strain on professional drivers’ Work Traffic Crashes (WTCs). This research was performed using the data collected from a sample of 753 professional drivers, responding to a self-report questionnaire on job strain (work stress indicator of the Job Demand-Control model), driving styles and work-traffic safety outcomes suffered in the past two years. Regression-based moderation analyses suggest that the job strain of professional drivers is positively associated with the occupational traffic crashes they suffer, and that such association is stronger in drivers with “reckless & careless”, “anxious”, and “angry & hostile” driving styles. Meanwhile, the “patient & careful” (positive) driving style was not associated with a lower risk of suffering a WTC, nor with a lower vulnerability to stress-related WTCs. The results of this study support the hypothesis that driving styles exert a statistical moderation between the job strain and the occupational traffic crashes suffered by professional drivers. These findings may support the design of evidence-based interventions in both the organizational and individual levels, focused stress-related factors and driving styles as predictors of work traffic crashes.     

教育价值观和逆境信念在家庭经济压力与初中生学业成就之间的作用

大量研究表明,家庭经济压力对青少年学业成就具有显著的不利影响。但是,目前学界对家庭经济压力“怎样”（中介机制）以及“何时”（调节机制）影响青少年学业成就仍知之甚少。本研究在整合贫困文化模型及心理韧性理论的基础上构建一个有调节的中介模型,考察青少年教育价值观（读书是否有用）在家庭经济压力与学业成就之间的中介作用,同时检验中国文化逆境信念对该中介路径的调节作用。采用随机整群抽样,选取四川省9所普通中学1613名初中生（平均年龄13.42岁,SD = 1.22）作为研究对象。被试匿名填写家庭经济压力问卷、教育价值观问卷、中国文化逆境信念量表以及学业成就问卷。结果表明：（1）在控制了性别、年龄等人口学变量后,家庭经济压力显著负向预测学业成就。（2）教育价值观在家庭经济压力与学业成就之间具有部分中介作用。（3）积极逆境信念能缓冲家庭经济压力对教育价值观的消极作用,进而减少对学业成就的不利影响。本研究证实了“读书无用论”是经济困难与学业成就的重要联系机制,并肯定了中国文化逆境信念对经济困难青少年的保护作用。这一内在保护机制的揭示对教育实践有一定的启示。     

Relations between stress and work outcomes: The role of felt challenge, job control, and psychological strain

Recent research on reported work stress indicates stress may not always be deleterious for an individual or organization. Research in this area, however, has not yet examined a variety of work outcomes, the mechanism by which stress leads to such outcomes, and the moderators of this effect. The present study hypothesized that two types of reported stress (challenge- and hindrance-related) have a divergent relationship with work outcomes (relating to desirable and undesirable outcomes, respectively) and a similar (positive) relationship with psychological strain. We also hypothesize felt challenge as a mechanism through which challenge stress relates to desirable outcomes and job control as a moderator of the effect. Results from a heterogeneous sample of university staff employees (N=461) supported many of the hypotheses. The two types of stress differentially related to work outcomes yet both positively related to psychological strain. In addition, felt challenge mediated the relationship between challenge-related stress and work outcomes, yet the effect of challenge-related stress did not depend on job control.     

Exploring links between polychronicity and well-being from the perspective of person–job fit: Does it matter if you prefer to do only one thing at a time?

This research examined polychronicity, which refers to an individual’s preference for working on many things simultaneously as opposed to one at a time. It was hypothesized that supplies–values fit on this temporal variable is related to well-being. Specifically, it was predicted that deficient and excess polychronicity supplies are associated with poorer well-being, and that well-being is uniformly high along the continuum of polychronicity fit. It was also hypothesized that fit effects are stronger for individuals who place high importance on how their time is allocated than for individuals who place low importance on that dimension. Participants in Study 1, a laboratory experiment, were students (N = 266); participants in Study 2, conducted in a field setting, were employees of Canadian organizations (N = 746). No fit effects were observed in Study 1. Consistent with the hypotheses, however, fit on the dimension of polychronicity was related to job satisfaction, self-efficacy, and psychological strain in Study 2. The role of value importance as a moderator of the relation between supplies–values fit and well-being was not supported.     

The relationship between dynamic strain aging and serrated flow behaviour in magnesium alloy

The relationship between dynamic strain ageing (DSA) and serrated flow has been investigated via alternately switching strain rates at various temperatures in a Mg–3Nd–1Zn alloy. The results reveal that serrated flow is enhanced with decreasing strain rate and increasing temperature and tends to vanish, while the DSA continually intensifies as revealed by a higher flow stress even after the serration flow disappears. A mechanism is proposed, which could explain some abnormal deformation behaviour, such as a negative strain rate sensitivity and thermal hardening.     

The influence of family environment and child temperament on work/family role strain for mothers and fathers

This study examined the additive effect of structural variables, child characteristics, and the family environment on mothers' and fathers' work/family role strain. Differences between mothers and fathers on these variables were also examined. The sample consisted of 36 dualearner families whose children had been in daycare from infancy through 4 years of age. Structural variables included work schedules and time spent with child for mothers only, fathers only, and both parents together with child. Child characteristics included temperament and health. Family environment variables included different components of the family environment (conflict, cohesion, expressiveness, organization, and control) and parenting daily hassles. Results showed that mothers' time with child and caregiving for child were greater than fathers'. Mothers reported more expressiveness in the family and more daily hassles with children than fathers. Mothers' level of role strain was also significantly higher than fathers'. For mothers, role strain was associated with hours away from home, child sociability, family conflict, and daily hassles resulting in an R² of 0.57. Fathers' role strain was associated with family expressiveness, organization, and their wives' daily hassles resulting in an R² of 0.37. Data suggest that mothers' and fathers' role strain may be driven by somewhat different factors. For women, aspects of the family and the child and work hours accounted for a considerable portion of the variance while for men, only aspects of the family environment were associated with their level of role strain. Copyright © 2003 John Wiley & Sons, Ltd.