Avoidance of Heights on the Visual Cliff in Newly Walking Infants

Work with infants on the “visual cliff” links avoidance of drop‐offs to experience with self‐produced locomotion. Adolph's (2002) research on infants' perception of slope and gap traversability suggests that learning to avoid falling down is highly specific to the postural context in which it occurs. Infants, for example, who have learned to avoid crossing risky slopes while crawling must learn anew such avoidance when they start walking. Do newly walking infants avoid crossing the drop‐off of the visual cliff? Twenty prewalking but experienced crawling infants were compared with 20 similarly aged newly walking infants on their reactions to the visual cliff. Newly walking infants avoided moving onto the cliff's deep side even more consistently than did the prewalking crawlers. Thus, in the context of drop‐offs in visual texture, our results show that once avoidance of drop‐offs is established under conditions of crawling, it is developmentally maintained once infants begin walking.     

The attitudes of American sociologists toward causal theories of male homosexuality

The origin of homosexuality has been the subject of systematic study in many disciplines during the previous century. In the social science literature, two general models concerning the etiology of homosexuality have emerged, the essentialist model and the constructionist model. This article reviews these two models and provides empirical data on their relative support. Support for each model has been gauged by assessing the opinions of sociologists. Data was obtained from a random sample of sociologists teaching in colleges and universities throughout the United States. The major finding is that the majority of sociologists now endorse the essentialist position.     

Housing Well-Being: Developing and Validating a Measure

Housing well-being refers to the home resident’s cumulative positive and negative affect associated with the purchase, preparation, ownership, use, and maintenance of the current home, and the selling of the previous home. Housing well-being is assumed to occur when the home is bought with the least amount of effort (purchase), the home is prepared for use to meet the needs of the new occupants (preparation), ownership signals status and enhances the home owner’s financial portfolio (ownership), the home serves the housing needs of the residents (use), the maintenance, renovation, and repair in the home are minimal, least costly, and effortless (maintenance), and the sale of the home is transacted with the least amount of effort and most financial gain (selling). Based on this conceptualization of housing well-being, we conducted an exploratory study to identify the sources of satisfaction related to the purchase, preparation, ownership, use, and maintenance of the current home, and the selling of the previous home. The exploratory study also helped us articulate a theoretical model describing the interrelationships among the housing well-being constructs and their consequence: the perceived quality-of-life (QOL) impact of the home. The exploratory study helped us also to develop survey measures, which in turn were validated through two additional studies involving surveys of home owners in the US and Korea.     

垄断竞争和最优的产品多样化

比较分析在垄断力量存在时市场均衡及最优资源分配的各种情形就会发现,垄断力量和市场扭曲的方向并没有显著的关系,在弹性不变的效用函数情形下,市场解能达到有约束的帕累托最优,而与弹性数值无关。对于可变弹性,市场解对最优的偏离是不确定的。具有非对称的需求和非对称的成本的条件下,市场偏离无弹性和高成本的商品。     

Work,Family, and Mental Health: Testing Different Models of Work‐Family Fit

Using family resilience theory, this study examined the effects of work‐family conflict and work‐family facilitation on mental health among working adults to gain a better understanding of work‐family fit. Data from the National Survey of Midlife Development in the United States (MIDUS) were used to compare different combinations of work‐family conflict and work‐family facilitation. Results suggest that family to work facilitation is a family protective factor that offsets and buffers the deleterious effects of work‐family conflict on mental health. The results across these outcomes suggest that work‐family conflict and facilitation must be considered separately, and that adult mental health is optimized when family to work facilitation is high and family to work and work to family conflict is low.     

Do workers want OSHA’s ergonomics regulations?

conclusion OSHA’s proposed Ergonomics Rule will clearly impose serious costs on firms across many industries, but industries where MSD risk is highest will face much greater costs. OSHA recognizes this by excluding some high-risk industries. For the higher risk indus-tries that are covered by the proposal, OSHA suggests that benefits to firms and employ-ees will outweigh these costs. We argue that OSHA has ignored the importance of differences in individual preferences for accepting risk and that compensating wage differentials allow different individuals to maximize their utility by making trade-offs between safety and wages.     

The effect of sexual abstinence on females' educational attainment

A number of studies have shown that teenagers who abstain from sex are more likely to graduate from high school and attend college than their sexually active peers. However, it is unclear whether this association represents a causal relationship or can be explained by unmeasured heterogeneity. We employ a variety of statistical techniques to distinguish between these hypotheses, using data on females from the National Longitudinal Study of Adolescent Health. Our results provide evidence that delaying first intercourse leads to an increased likelihood of graduating from high school. This relationship appears to be strongest among respondents in the bottom third of the ability distribution. Controlling for fertility reduces, but does not eliminate, the estimated effect of delaying intercourse.