Social Environmental Variation, Plasticity Genes, and Aggression: Evidence for the Differential Susceptibility Hypothesis

Although G×E studies are typically based on the assumption that some individuals possess genetic variants that enhance their vulnerability to environmental adversity, the differential susceptibility perspective posits that these individuals are simply more susceptible to environmental influence than others. An important implication of this model is that those persons most vulnerable to adverse social environments are the same ones who reap the most benefit from environmental support. The present study tested several implications of this proposition. Using longitudinal data from a sample of several hundred African Americans, we found that relatively common variants of the dopamine receptor gene and the serotonin transporter gene interact with social environmental conditions to predict aggression in a manner consonant with differential susceptibility. When the social environment was adverse, individuals with these genetic variants manifested more aggression than other genotypes, whereas when the environment was supportive they demonstrated less aggression than other genotypes. Further, we found that these genetic variants interact with environmental conditions to foster various cognitive schemas and emotions in a manner consistent with differential susceptibility and that a latent construct formed by these schemas and emotions mediated the effect of gene by environment interaction on aggression.     

How robust is the rationality assumption in economics? A statistical test based on student grade distributions

This note re-addresses the question of the rationality of economic actors in a new setting. We examine the distribution of final course grades for a “Principles of Economics Class” in an effort to draw conclusions about rational student work effort. Based on the concepts of the opportunity cost of time, the relative reward for earning various grades (based on university codes for determining grade points) and the concept of rationality, we expect to find a greater percentage of grades at the lower end of the distribution for each grade level. We find statistical evidence that there are more students at the lower end of each grade interval than at the upper end. This result is consistent with what economists have long conjectured: students are rational in the allocation of study time.     

Requisite Variety of Strategic Management Modes: A Cultural Study of Strategic Actions in a Deterministic Environment

This article presents the results of a qualitative study that examines the modes by which strategy emanates in a nonprofit human services organization, externally controlled by its funding sources. The strategy-making process is broached by proposing a taxonomy of strategic modes arranged into the Hrebiniak and Joyce (1985) framework. In light of Ashby's law of requisite variety (1968), this study contends that the subject organization's context of environmental determinism should lead to a culturally based configuration of traditional, spontaneous, and dialectical modes. The results support the proposition for requisite variety. This research presents valuable implications for the study and practice of strategic management-especially regarding strategic learning and change within externally controlled nonprofit organizations.     

An Improved Range Estimator of Sigma for Determining Sample Sizes

The use of a range estimator of the population standard deviation, sigma (σ), for determining sample sizes is discussed in this study. Standardized mean ranges (d_n's), when divided into the ranges of sampling frames, provide estimates of the standard deviation of the population. These estimates can be used for determining sample sizes. The d_n's are provided for seven different distributions for sampling frame sizes that range from 2 to 2000, For each of the seven distributions, functional relationships are developed such that d_n = f(n_SF) where n_SF is the size of the sample frame. From these functions, d_n's can be estimated for sampling frame sizes which are not presented in the study.     

Drivers and Outcomes of Long‐term Orientation in Cooperative Relationships

We argue in this paper that a buyer may deliberately develop long‐term orientation as a governance mechanism to deal with risks arising from exchange hazards, and to reduce the opportunistic behaviour of a supplier. While the exchange hazards of asset specificity pose a safeguarding problem, those of market uncertainty pose an adaptation problem. We test our model on a sample of 221 procurement partnerships. Our results show that satisfactory prior history of a supplier, asset specificity of the buyer and market uncertainty are all positively related to a buyer's long‐term orientation towards a supplier. Consistent with the idea that asset specificity and market uncertainty pose different governance problems, we find that satisfactory prior history reduces the positive relationship between asset specificity and a buyer's long‐term orientation, but enhances the positive relationship between market uncertainty and a buyer's long‐term orientation. We also find that a buyer's long‐term orientation fully mediates the relationship between satisfactory prior history and a supplier's opportunistic behaviour. Finally, implications on the theory and the practices of relationship governance are discussed.     

Living life for others and/or oneself: The social development of life orientations

A range of social science research suggests Americans are becoming more self-oriented over time, and that this focus comes at a cost to general concern with community. Examining data from a large-scale national study of college students, we explore this influential hypothesis on two fronts. First, we empirically investigate whether people who are especially concerned with personal achievement are necessarily less concerned about contributing to their community. Contrary to most iterations of the individualism thesis, we find that significant numbers of individuals are concerned with both personal success and political/social involvement. To explore further, we expand this supposed single dimension into a fourfold typology, showing that many people are ‘idealists’ (concerned with both self and others) and ‘apathists’ (relatively unconcerned with either). After broadening the taken-for-granted egoist/altruist continuum, we explore antecedent social structural, aspirational, and social psychological factors that predict membership in these value preference groups. The findings from our preliminary model suggest that these broad orientations are shaped by a complex array of factors across multiple domains.     

An Assessment of America's Tobacco-Free Colleges and Universities

Abstract

Objective: This study examined the extent to which US campuses identified as “100% tobacco-free” by the American Lung Association of Oregon adhered to the American College Health Association's the most recent guidelines and recommendations promoting tobacco-free environments in colleges and universities. Participants: A key informant from 162 of 175 institutions (92.6% response rate) completed an online survey between January 2010 and February 2010. Methods: The variables under study were assessed via a cross-sectional research design. Participants completed a 35-item survey regarding their school's tobacco policies, procedures, and enforcement practices. Results: Although the vast majority of schools had written policies and procedures in place, schools with current policies were the most compliant. Numerous opportunities for improved adherence were identified in the results. Conclusions: Findings from this study may help institutions in the development and implementation of a new tobacco policy, as well as strengthen policies among existing tobacco-free schools.