The purpose of this study was to test the directionality of influence between reading comprehension (RC) and print exposure (PE), thereby estimating genetic and environmental effects of this relation. The sample consisted of 910 twins in fourth through ninth grades (M[subscript age] = 12.33 years, SD = 1.41) from the Florida Twin Project on…

This paper examines the effects of three large, coal-fired power plant closures on student absences and achievement in the Chicago area. We find that schools near the plants experienced a 7 percent reduction in absences relative to those further away following the closures. Math achievement in these schools increased following the closures,…

Background: A better understanding of the nature and etiology of conduct disorder (CD) can inform nosology and vice versa. We posit that any prevalent form of psychopathology, including CD, can be best understood if it is studied in the context of other correlated forms of child and adolescent psychopathology using formal models to guide inquiry.…

Epidemiology uses strong sampling methods and study designs to test refutable hypotheses regarding the causes of important health, mental health, and social outcomes. Epidemiologic methods are increasingly being used to move developmental psychopathology from studies that catalogue correlates of child and adolescent mental health to designs that…

Background: Recent studies suggest that the association between maternal age at childbearing (MAC) and children's disruptive behaviors is the result of family factors that are confounded with both variables, rather than a casual effect of environmental factors specifically related to MAC. These studies, however, relied on restricted samples and…

The frequency of judgment effect is a special case of Response Mode effect in human covariation and causal learning. Judgment adjustment -to [Delta]P-, depends on the trial type preceding that judgment, but that effect is restricted to situations in which participants are asked to make their judgments with a high frequency. Two experiments further…