On using multiple imputation for exploratory factor analysis of incomplete data

A simple multiple imputation-based method is proposed to deal with missing data in exploratory factor analysis. Confidence intervals are obtained for the proportion of explained variance. Simulations and real data analysis are used to investigate and illustrate the use and performance of our proposal.     

Treatment Effect on Recidivism for Juveniles Who Have Sexually Offended: a Multilevel Meta-Analysis

The current study investigated the effect on recidivism of treatment aimed at juveniles who have sexually offended. It also assessed the potential moderating effect of type of recidivism, and several treatment, participant and study characteristics. In total, 14 published and unpublished primary studies, making use of a comparison group and reporting on official recidivism rates, were included in a multilevel meta-analysis. This resulted in the use of 77 effect sizes, and 1726 participants. A three-level meta-analytic model was used to calculate the combined effect sizes (Cohens d) and to perform moderator analyses. Study quality was assessed with the EPHPP Quality Assessment Tool for Quantitative Studies. A moderate effect size was found (d = 0.37), indicating that the treatment groups achieved an estimated relative reduction in recidivism of 20.5% as compared to comparison groups. However, after controlling for publication bias, a significant treatment effect was no longer found. Type of recidivism did not moderate the effect of treatment, indicating that treatment groups were equally effective for all types of recidivism. Also, no moderating effects of participant or treatment characteristics were found. Regarding study characteristics, a shorter follow up time showed a trend for larger effect sizes, and the effect size calculation based on proportions yielded larger effect sizes than calculation via mean frequency of offending. Implications for future research and clinical practice are discussed.     

Studies on wild house mice VI: Differential effects of the Y chromosome on intermale aggression

The aim of this study is to determine the effects of different parts of the Y chromosome of wild house mice on aggression. To reach this goal, intercrosses were made between two selection lines for attack latency (SAL and LAL) and their congenic strains (SAL. LY and LAL. SY). This procedure resulted in F₁ hybrids that carried the same autosomes, but differed in their X chromosome and the two different parts of their Y chromosomes, the different parts of the Y chromosome being a recombining part called the pseudoautosomal region (PAR) and a non-recombining part (non-PAR). We conclude that both parts of the Y chromosome contribute slightly but significantly to variation in aggression. The major effect is accomplished by the PAR of the aggressive parent; a mirror effect is achieved by the non-PAR of the aggressive parent in interaction with the PAR. © 1994 Wiley-Liss, Inc.     

Studies on wild house mice iv: On the heredity of testosterone and readiness to attack

An attempt was made to determine the role of the Y chromosome in the development of aggression in wild house mice. The aggression-eliciting property of testosterone depends not only on circulating adult testosterone, but also on perinatal sensitization of the central nervous system to this steroid. Results of crosses between aggressive (SAL) and non-aggressive (LAL) mice indicate that adult plasma testosterone in these mice is determined by the autosomes, high testosterone levels being dominant over low levels. Conversely, the Y-chromosomal effect seems related to perinatal processes that sensitize the brain for testosterone.     

Computational and statistical methods for analyzing event-related potential data

Some computational and statistical techniques that can be used in the analysis of event-related potential (ERP) data are demonstrated. The techniques are fairly elementary but go one step further than do simple area measurement or peak picking, which are most often used in ERP analysis. Both amplitude and latency measurement techniques are considered. Principal components analysis (PCA) and methods for electromyographic onset determination are presented in detail, and Woody filtering is discussed briefly. The techniques are introduced in a nontechnical, tutorial review style. One and the same existing data set is presented, to which the techniques are applied, and practical guidelines for their use are given. The methods are demonstrated against a background of theoretical notions that are related to the definition of ERP components.     

Development and learning: a TASC-based perspective of the acquisition of perceptual-motor behaviors

The concepts of development and learning are discussed in terms of different theoretical orientations to the study of motor behavior. It is argued that although these concepts are commonly used to discuss various aspects of change across the life span, there is little agreement regarding the definition of these terms and even whether these are useful concepts for researchers studying change over time. A theoretical approach, the TASC-based approach is presented as an alternative account for examining change over time. The TASC label stands for a focus on particular tasks, adaptation and selection of behaviors as a function of constraints. This account is grounded in evolutionary theory and assumes that variability, selection, and adaptation are central to change over time within individuals. Emphasis is placed on the tasks individuals attempt to solve in achieving particular goals given the constraints of the local environment and the organism. An alternative manner to conceptualize the concepts of development and learning are presented within the TASC-based approach.     

The relation between infants' perception of catchableness and the control of catching

The authors studied how infants come to perceive and act adaptively by presenting 35 three- to nine-month-olds with balls that approached at various speeds according to a staircase procedure. They determined whether infants attempted to reach for the ball and whether they were successful (i.e., contacted the ball). In addition, the time and distance of the ball at the onset of the catching movements were measured for the successful interceptions. The authors found that not only catching skill but also the perceptual judgments of the catchableness improved with age; infants started to take their catching ability into account when judging whether a ball was catchable. Moreover, the authors observed that infants who made imprecise perceptual judgments were more likely to use a distance control strategy, whereas infants who made accurate perceptual judgments were more likely to use the more adaptive time strategy to control the catching movements. They conclude that the present study supports the proposal that, even in prelocomotor infants, the development of perception is intricately linked to or constrained by development in the visual control of action.