Dopaminergic polymorphisms and educational achievement: results from a longitudinal sample of Americans

Although educational attainment has been found to be moderately heritable, research has yet to explore candidate genes for it. Drawing on data from the National Longitudinal Study of Adolescent Health, in the current study, we examined the association between polymorphisms in three dopaminergic genes (DAT1, DRD2, and DRD4), a dopamine index, and educational attainment. Statistically significant effects were found for DAT1, DRD2, DRD4, and the dopamine index for highest level of education. This study is the first to our knowledge that links measured genes to educational attainment.     

Influencing organizational commitment through office redesign

Prior research on the effects of office redesign on work-related outcomes has been largely atheoretical and yielded mixed and conflicting findings. Expanding on individual reactions to office design changes as specified by social interference theory, we propose that office redesign affects organizational commitment and this relationship is mediated by employee perceptions of the broader work environment. This conceptual model is tested using 121 financial services employees who experience office redesign and 136 who do not. Results indicate that perceptions of innovation and collaboration mediate the effects of office redesign over and above negative personal reactions such that affective organizational commitment is enhanced among those experiencing reconfigured offices. Findings provide support for an expanded rendition of social interference theory that provides for favorable (as well as unfavorable) employee reactions to office redesign. Such a theoretical explanation is asserted to increase understanding of how the physical environment influences employee attitudes.     

Patterns of strengths and weaknesses in children's knowledge about fractions

The purpose of this study was to explore individual patterns of strengths and weaknesses in children's mathematical knowledge about common fractions. Tasks that primarily measure either conceptual or procedural aspects of mathematical knowledge were assessed with the same children in their fourth- and fifth-grade years (N=181, 56% female and 44% male). Procedural knowledge was regressed on levels of conceptual knowledge, and vice versa, to obtain residual scores. Residual scores capture variability in each kind of math knowledge that is not shared with the other type of knowledge. Cluster analysis using residuals indicated four distinct knowledge profiles in fourth graders: (a) higher than expected conceptual knowledge and relatively lower procedural knowledge, (b) relatively lower conceptual knowledge and higher procedural knowledge, (c) lower concepts but expected levels of procedural knowledge, and (d) relatively higher than expected levels of both procedural and conceptual knowledge. In fifth grade, another cluster emerged that showed lower procedures but expected levels of conceptual knowledge. In general, students with relatively lower than expected conceptual knowledge showed poorer accuracy on measures used to form the clusters and also word problem setups and estimation of sums. Implications for explaining seemingly conflicting results from prior work across studies are discussed.     

The emergence of tool use during the second year of life

Despite a growing interest in the question of tool-use development in infants, no study so far has systematically investigated how learning to use a tool to retrieve an out-of-reach object progresses with age. This was the first aim of this study, in which 60 infants, aged 14, 16, 18, 20, and 22months, were presented with an attractive toy and a rake-like tool. There were five conditions of spatial relationships between the toy and the tool, going from the toy and tool being connected to there being a large spatial gap between them. A second aim of the study was to evaluate at what age infants who spontaneously fail the task can learn this complex skill by being given a demonstration from an adult. Results show that even some of the youngest infants could spontaneously retrieve the toy when it was presented inside and touching the top part of the tool. In contrast, in conditions with a spatial gap, the first spontaneous successes were observed at 18months, suggesting that a true understanding of the use of the tool has not been fully acquired before that age. Interestingly, it is also at 18months that infants began to benefit from the demonstration in the conditions with a spatial gap. The developmental steps for tool use observed here are discussed in terms of changes in infants' ability to attend to more than one item in the environment. The work provides insight into the progressive understanding of tool use during infancy and into how observational learning improves with age.     

Experimenter Effects on Cardiovascular Reactivity and Task Performance During Mental Stress Testing

The Psychological Record - Experimenter effects have long been hypothesized to influence participants’ responses to mental stress testing. To explore the influence of experimenter warmth on...