Circular interpretation of regression coefficients

The interpretation of the effect of predictors in projected normal regression models is not straight-forward. The main aim of this paper is to make this interpretation easier such that these models can be employed more readily by social scientific researchers. We introduce three new measures: the slope at the inflection point (b_c), average slope (AS) and slope at mean (SAM) that help us assess the marginal effect of a predictor in a Bayesian projected normal regression model. The SAM or AS are preferably used in situations where the data for a specific predictor do not lie close to the inflection point of a circular regression curve. In this case b_c is an unstable and extrapolated effect. In addition, we outline how the projected normal regression model allows us to distinguish between an effect on the mean and spread of a circular outcome variable. We call these types of effects location and accuracy effects, respectively. The performance of the three new measures and of the methods to distinguish between location and accuracy effects is investigated in a simulation study. We conclude that the new measures and methods to distinguish between accuracy and location effects work well in situations with a clear location effect. In situations where the location effect is not clearly distinguishable from an accuracy effect not all measures work equally well and we recommend the use of the SAM.     

Early Parenting Intervention: Family Risk and First-time Parenting Related to Intervention Effectiveness

The effects of cumulative risk and parity on the effectiveness of a home based parenting intervention were tested in a randomized controlled trial with 237 families with 1- to 3-year-old children screened for high levels of externalizing behavior. The intervention was aimed at enhancing positive parenting and decreasing externalizing behaviors. The results showed that cumulative risk was not associated with either change in child externalizing behaviors or change in positive parenting. When intervention effectiveness was compared for primiparas (i.e., first-time mothers) versus multiparas (i.e., mothers with more than one child), we found that intervention mothers of first-born children displayed an increase in their use of positive discipline strategies as compared to first-time mothers in the control group, whereas a similar effect for multiparas was absent. Among multiparas we found an intervention effect on sensitivity, with control group mothers showing an increase in sensitivity, whereas the intervention group showed a constant level of sensitivity over time. These results suggest that parity may be a moderator of intervention effectiveness. Implications for investigating moderators of intervention effectiveness are discussed.     

Experimental evidence for differential susceptibility: dopamine D4 receptor polymorphism (DRD4 VNTR) moderates intervention effects on toddlers' externalizing behavior in a randomized controlled trial

In a randomized controlled trial we tested the role of genetic differences in explaining variability in intervention effects on child externalizing behavior. One hundred fifty-seven families with 1- to 3-year-old children screened for their relatively high levels of externalizing behavior participated in a study implementing Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline (VIPP-SD), with six 1.5-hr intervention sessions focusing on maternal sensitivity and discipline. A moderating role of the dopamine D4 receptor (DRD4) variable-number tandem repeat (VNTR) exon III polymorphism was found: VIPP-SD proved to be effective in decreasing externalizing behavior in children with the DRD4 7-repeat allele, a polymorphism that is associated with motivational and reward mechanisms and Attention Deficit Hyperactivity Disorder (ADHD) in children. VIPP-SD effects were largest in children with the DRD4 7-repeat allele whose parents showed the largest increase in the use of positive discipline. The findings of this first experimental test of (measured) gene by (observed) environment interaction in human development indicate that children may be differentially susceptible to intervention effects depending on genetic differences.     

Justice and the human alarm system: The impact of exclamation points and flashing lights on the justice judgment process

Extending theory within the justice domain and work on the human alarm system, the current paper argues that the process by which justice judgments are formed may be influenced reliably by the activation of psychological systems that people use to detect and handle alarming situations. Building on this analysis, it is further proposed that if this line of reasoning is true then presenting alarm-related stimuli, such as exclamation points and flashing lights, to people should lead to more extreme judgments about subsequent justice-related events than not presenting these alarming stimuli. Findings collected using different experimental paradigms provide evidence supporting these predictions both inside and outside the psychology lab. Implications for the social psychology of justice and the human alarm system literature are discussed.     

Observation of early childhood physical aggression: a psychometric study of the system for coding early physical aggression

We investigated the reliability and (convergent and discriminant) validity of an observational measure of physical aggression in toddlers and preschoolers, originally developed by Keenan and Shaw [1994]. The observation instrument is based on a developmental definition of aggression. Physical aggression was observed twice in a laboratory setting, the first time when children were 1-3 years old, and again 1 year later. Observed physical aggression was significantly related to concurrent mother-rated physical aggression for 2- to 4-year-olds, but not to maternal ratings of nonaggressive externalizing problems, indicating the measure's discriminant validity. However, we did not find significant 1-year stability of observed physical aggression in any of the age groups, whereas mother-rated physical aggression was significantly stable for all ages. The observational measure shows promise, but may have assessed state rather than trait aggression in our study.     

Simultaneous media usage: a critical consumer orientation to media planning

This research study is the third in a series of surveys exploring the incidence of simultaneous media usage among a national sample of US consumers. The research is based on 12,322 respondents who were sampled via an online network. The findings show that simultaneous media usage, ie multiple exposures to various media forms at a single point in time for the same media consumer, occurs in and among a substantial portion of the US media population. The existence of simultaneous media exposures, created by multi‐tasking consumers, is a fact in today's media marketplace. The existence of simultaneous media exposures undermines most current media measurement systems as they are defined as isolated environments. Thus, the challenge of this paper is for media management to rethink how media evaluations should be rethought for the 21st century. Copyright © 2004 Henry Stewart Publications Ltd.     

An enquiry concerning the principles of cultural norms and values: The impact of uncertainty and mortality salience on reactions to violations and bolstering of cultural worldviews

This enquiry concerning the principles of cultural norms and values focuses on the impact of mortality and uncertainty salience on people’s reactions to events that violate or bolster their cultural norms and values. Five experiments show that both mortality and uncertainty salience influence people’s reactions to violations and bolstering of their cultural worldviews, yielding evidence for both terror and uncertainty management theories. Interestingly, the five experiments consistently reveal that uncertainty salience has a bigger impact on people’s reactions than mortality salience, suggesting that the former may be a more important antecedent of reactions to norms and values than the latter. Findings further suggest that uncertainty salience did not instigate death-thoughts whereas reactions to norms and values were stronger among mortality salient participants who thought of uncertainty as a result of the mortality salience manipulation than mortality salient participants who did not think of uncertainty following this manipulation. Implications are discussed.     

The impact of brief teacher training on classroom management and child behavior in at-risk preschool settings: Mediators and treatment utility

Teachers from fourteen classrooms were randomly assigned to an adaptation of Incredible Years (IY) teacher training or to teacher training-as-usual. Observations were made of the behavior of 136 target preschool boys and girls nominated by teachers as having many or few conduct problems. Peer and teacher behavior were observed at baseline and post training. IY training resulted in increases in teachers' positive and reductions in teachers' negative behavior relative to training as usual, in decreased peer negative behavior toward target children, and in decreased negative behavior of target children high on conduct problems. The impact of IY training on the behavior of target children was mediated by changes in peers' behavior with no direct effects of teacher behavior and differential effects for high and low conduct problem children. Teacher training focused on altering the whole classroom environment may be an effective strategy, even for children with significant conduct problems.