Genetic and environmental influences on academic achievement trajectories during adolescence

Most studies have considered the effects of particular characteristics on academic achievement individually, which means that little is known about how they function together. Using the population-based Minnesota Twin Family Study, the authors investigated the effects of child academic engagement (interest, involvement, effort), IQ, depression, externalizing behavior, and family environmental risk on academic achievement (reported school grades) from ages 11 through 17. Hierarchical linear growth curve modeling showed main effects on initial reported Grades for all variables, and IQ mitigated the deleterious effects of family risk and externalizing. Only engagement affected change in Grades through adolescence. Influences on initial Grades were strongly genetically influenced, associated primarily with IQ, engagement, and externalizing behavior. Shared environmental influences on initial Grades linked engagement, IQ, and family risk. Genetic influences on change in Grades were substantial, but they were not associated with the academic, family risk, and mental health covarying factors. These results indicate that age 11 achievement and change in achievement through adolescence show systematic patterns and document the existence of individual differences in the commonly shared developmental experience of adapting to the school environment.     

Replacing relative reinforcing efficacy with behavioral economic demand curves

Relative reinforcing efficacy refers to the behavior-strengthening or maintaining property of a reinforcer when compared to that of another reinforcer. Traditional measures of relative reinforcing efficacy sometimes have led to discordant results across and within studies. By contrast, previous investigations have found traditional measures to be congruent with behavioral economic measures, which provide a framework for integrating the discordant results. This study tested whether the previously demonstrated congruence between traditional relative reinforcing efficacy measures and behavioral economic demand curve measures is sufficiently robust to persist when demand for one reinforcer is altered. Cigarette smokers pulled plungers for cigarettes or two magnitudes of money on progressive-ratio schedules that increased the response requirement across sessions. Demand for the two different reinforcers was assessed in single-schedule and concurrent-schedule sessions. Demand curve measures Pmax and Omax correlated significantly with traditional measures of breakpoint and peak response rate, respectively. Relative locations of demand curves for money and cigarettes under single schedules predicted preference in concurrent schedules in most cases. Although measures of relative reinforcing efficacy for money changed with money magnitude, the congruence between traditional and behavioral economic measures remained intact. This robust congruence supports the proposal that demand curves should replace measures of relative reinforcing efficacy. The demand curve analysis illustrates why concordance between traditional measures is expected under some experimental conditions but not others.     

Moving from cognition to behavior: What the research says

In 1994, R. G. Lord and P. E. Levy proposed a variant of control theory that incorporated human information processing principles. The current article evaluates the empirical evidence for their propositions and updates the theory by considering contemporary research on information processing. Considerable support drawing from diverse literatures was found for propositions concerning the activation of goal-relevant information, the inhibition of goal-irrelevant information, and the consequences of goal completion. These effects were verified by meta-analytic analyses, which also supported the meaningfulness of such effects on the basis of their unstandardized magnitudes. The authors conclude by proposing new directions for this version of control theory by invoking recent theorizing on goal emergence and the importance of velocity and acceleration information for goal striving and by reviewing research in cognitive neuroscience.     

Survey return rates as a function of priority versus first-class mailing

Prior research indicates survey procedures that signal significance and individualized mailings have higher response rates. Thus, it was hypothesized that surveys delivered via Priority mail would result in higher return rates than surveys delivered via First-Class. 260 surveys were sent to individuals randomly selected from lists of licensed physical and behavioral healthcare providers in Alaska and New Mexico. Half of the selected individuals were assigned randomly to receive mailings using Priority mail, the other half received First-Class mailings. Return rate was 39% for First-Class and 35% for Priority. Z tests of proportion indicated no statistically significant differences between methods. Given increased costs with no resultant increase in response rate, sending surveys to potential participants via Priority mail does not appear warranted.     

The National Institutes of Health (NIH) State-Of-the-Science Conference on Preventing Violence and Related Health-Risking Social Behaviors in Adolescents — A Commentary

Although youth in the United States remain substantially more violent than adolescents and young adults in most industrial countries, the National Institutes of Health's (NIH) State-of-the-Science Conference on Preventing Violence and Related Health-Risking Social Behaviors in Adolescents identified many reasons for optimism about our capacity to develop effective prevention and intervention responses. The research is getting better and contrary to popular opinion we do know a lot about what does work. Future advances will depend upon our insistence on the use of effectiveness evidence and the development of a taxonomy which will facilitate cross disciplinary communication.