Cry Babies and Pollyannas: Infants Can Detect Unjustified Emotional Reactions

Infants are attuned to emotional facial and vocal expressions, reacting most prominently when they are exposed to negative expressions. However, it remains unknown if infants can detect whether a person's emotions are justifiable given a particular context. The focus of the current paper was to examine whether infants react the same way to unjustified (e.g., distress following a positive experience) and justified (e.g., distress following a negative experience) emotional reactions. Infants aged 15 and 18 months were shown an actor experiencing negative and positive experiences, with one group exposed to an actor whose emotional reactions were consistently unjustified (i.e., did not match the event), while the other saw an actor whose emotional reactions were justified (i.e., always matched the event). Infants' looking times and empathic reactions were examined. Only 18‐month‐olds detected the mismatching facial expressions: Those in the unjustified group showed more hypothesis testing (i.e., checking) across events than the justified group. Older infants in the justified group also showed more concerned reactions to negative expressions than those in the unjustified group. The present findings indicate that infants implicitly understand how the emotional valence of experiences is linked to subsequent emotional expressions.     

Hidden champions: Exploring supportive family relationships of youth experiencing homelessness

The relationships that youth experiencing homelessness (YEH) have with supportive family members (i.e. those who provide them with social support) may be protective against risk behaviours and buffer adverse health outcomes. However, little is known about the nature of YEH's supportive family relationships and the type of social support that these family relationships offer them. Thus, we conducted in-depth interviews with 30 YEH to examine the type of social support received from family relationships and to explore the social dynamics of these relationships. We found that many YEH not only continued to maintain relationships with family members after becoming homeless but also received emotional and/or instrumental support from these family members. Beyond providing this type of social support, family members served as a source of motivation for these youth. Additionally, YEH contributed to their family relationships and gained a sense of connectedness in return. Lastly, we found that YEH's family support was influenced by their family circumstances and their need for autonomy. Collectively, our findings suggest there may be a need for interventions designed to strengthen relationships with supportive family members among YEH, who may derive multiple positive benefits from relating with the ‘hidden champions’ in their lives.     

The Role of Relative Cohort Size and Relative Income in the Demographic Transition

This paper summarizes the results of other analyses by the author with regard to the importance of relative cohort size (RCS) in determining male relative income (the income of young adults relative to prime-age workers) and general patterns of economic growth, and in turn influencing fertility in the currently more-developed nations. It then goes on to demonstrate that these same effects appear to have been operating in all of the one hundred-odd nations which have experienced the fertility transition since 1950. Parameter estimates based on the experience of all 189 countries identified by the United Nations between 1950 and 1995 are used to simulate the effects on fertility of migration from Third to First World countries. This exercise suggests that we get the best of all possible outcomes with migration: population is reduced in “overcrowded” Third World nations, total world population growth is substantially reduced, and scores of children are given the opportunity of growing up with all the educational and health advantages of U.S. residents.     

Analysis and Management of Periodic Review,Order‐Up‐To Level Inventory Systems with Order Crossover

In this article, we investigate the (R, S) periodic review, order‐up‐to level inventory control system with stochastic demand and variable leadtimes. Variable leadtimes can lead to order crossover, in which some orders arrive out of sequence. Most theoretical studies of order‐up‐to inventory systems under variable leadtimes assume that crossovers do not occur and, in so doing, overestimate the standard deviation of the realized leadtime distribution and prescribe policies that can inflate inventory costs. We develop a new analytic model of the expected costs associated with this system, making use of a novel approximation of the realized (reduced) leadtime standard deviation resulting from order crossovers. Extensive experimentation through simulation shows that our model closely approximates the true expected cost and can be used to find values of R and S that provide an expected cost close to the minimum cost. Taking account of, as opposed to ignoring, crossovers leads, on average, to substantial improvements in accuracy and significant cost reductions. Our results are particularly useful for managers seeking to reduce inventory costs in supply chains with variable leadtimes.