Book Reviews

Using a latent variable modelling strategy we study individual differences in patterns of answers to the selection task and to the truth table task. Specifically we investigate the prediction of mental model theory according to which the individual tendency to select the false consequent card (in the selection task) is negatively correlated with the tendency to judge the false antecedent cases as irrelevant (in the truth table task). We fit a psychometric model to two large samples (N = 486, twice), and find no evidence for this negative correlation. We examine which of the assumptions of the model theory must be amended to accommodate our findings.     

Expertise in biological conceptions: The case of the vineyard

To study how expertise impacts the understanding of a complex system like the vineyard, three measures were used with 259 participants (190 non-experts, 34 winemakers and/or winegrowers, and 35 biologists): a questionnaire to check for expertise (the Plant Biology Questionnaire), a task about the Structure, Behaviour and Function model, and a measure of the content of the participants’ discourse with the ALCESTE software. Results showed that biologists mentioned functions significantly more often than behaviours, whereas it was the opposite for winegrowers. Non-experts mentioned functions and behaviours significantly less frequently than experts did. The content analysis confirmed the differential expression of each kind of expertise: scientific wording for biologists, technical wording for winegrowers, and words focused on perceptible structures for the non-experts. Results from all tasks were highly correlated and allowed for an interpretation of expertise in terms of mental models of the vineyard.     

Truth table tasks: The relevance of irrelevant

Two types of truth table tasks are used investigating mental representations of conditionals: a possibilities-based and a truth-based one. In possibilities tasks, participants indicate whether a situation is possible or impossible according to the conditional rule. In truth tasks participants evaluate whether a situation makes the rule true or false, or is irrelevant with respect to the truth of the rule. Comparing the two-option version of the possibilities task with the truth task in Experiment 1, the possibilities task yields logical answer patterns whereas the truth task yields defective patterns. Adding the irrelevant option to the possibilities task in Experiment 2 leads to a considerable amount of defective patterns in the possibilities task, but still to more logical patterns in the possibilities task than in the truth task. Experiment 3 shows that directionality matters since rule-to-situation tasks yield more logical answer patterns than do situation-to-rule tasks. We conclude that both task types are not comparable as such since wording, number of options and directionality influence the results.     

Handling Missing Covariates in Conditional Mixture Models Under Missing at Random Assumptions

Mixture modeling is a popular method that accounts for unobserved population heterogeneity using multiple latent classes that differ in response patterns. Psychologists use conditional mixture models to incorporate covariates into between-class and/or within-class regressions. Although psychologists often have missing covariate data, conditional mixtures are currently fit with a conditional likelihood, treating covariates as fixed and fully observed. Under this exogenous-x approach, missing covariates are handled primarily via listwise deletion. This sacrifices efficiency and does not allow missingness to depend on observed outcomes. Here we describe a modified joint likelihood approach that (a) allows inference about parameters of the exogenous-x conditional mixture even with nonnormal covariates, unlike a conventional multivariate mixture; (b) retains all cases under missing at random assumptions; (c) yields lower bias and higher efficiency than the exogenous-x approach under a variety of conditions with missing covariates; and (d) is straightforward to implement in available commercial software. The proposed approach is illustrated with an empirical analysis predicting membership in latent classes of conduct problems. Recommendations for practice are discussed.     

A Comparison of Multilevel Imputation Schemes for Random Coefficient Models: Fully Conditional Specification and Joint Model Imputation with Random Covariance Matrices

Abstract

Literature addressing missing data handling for random coefficient models is particularly scant, and the few studies to date have focused on the fully conditional specification framework and “reverse random coefficient” imputation. Although it has not received much attention in the literature, a joint modeling strategy that uses random within-cluster covariance matrices to preserve cluster-specific associations is a promising alternative for random coefficient analyses. This study is apparently the first to directly compare these procedures. Analytic results suggest that both imputation procedures can introduce bias-inducing incompatibilities with a random coefficient analysis model. Problems with fully conditional specification result from an incorrect distributional assumption, whereas joint imputation uses an underparameterized model that assumes uncorrelated intercepts and slopes. Monte Carlo simulations suggest that biases from these issues are tolerable if the missing data rate is 10% or lower and the sample is composed of at least 30 clusters with 15 observations per group. Furthermore, fully conditional specification tends to be superior with intraclass correlations that are typical of crosssectional data (e.g., ICC?=?.10), whereas the joint model is preferable with high values typical of longitudinal designs (e.g., ICC?=?.50).     

Assessment of Multiple Membership Multilevel Models: An Application to Interviewer Effects on Nonresponse

Multilevel multiple membership models account for situations where lower level units are nested within multiple higher level units from the same classification. Not accounting correctly for such multiple membership structures leads to biased results. The use of a multiple membership model requires selection of weights reflecting the hypothesized contribution of each level two unit and their relationship to the level one outcome. The Deviance Information Criterion (DIC) has been proposed to identify such weights. For the case of logistic regression, this study assesses, through simulation, the model identification rates of the DIC to detect the correct multiple membership weights, and the properties of model variance estimators for different weight specifications across a range of scenarios. The study is motivated by analyzing interviewer effects across waves in a longitudinal study. Interviewers can substantially influence the behavior of sample survey respondents, including their decision to participate in the survey. In the case of a longitudinal survey several interviewers may contact sample members to participate across different waves. Multilevel multiple membership models are suitable to account for the inclusion of higher-level random effects for interviewers at various waves, and to assess, for example, the relative importance of previous and current wave interviewers on current wave nonresponse. To illustrate the application, multiple membership models are applied to the UK Family and Children Survey to identify interviewer effects in a longitudinal study. The paper takes a critical view on the substantive interpretation of the model weights and provides practical guidance to statistical modelers. The main recommendation is that it is best to specify the weights in a multiple membership model by exploring different weight specifications based on the DIC, rather than prespecifying the weights.     

Twins' Responses to Pleasant,Unpleasant, and Life Events

Pairs of monozygotic (n = 41) and same-sex dizygotic (n = 29) twins were administered the Pleasant Events Schedule, the Unpleasant Events Schedule (Lewinsohn & Amenson, 1978), and the Life Experiences Survey (Sarason, Johnson, & Siegel, 1978). These provided indices of both the frequency of and the emotional response to mood-related events. Monozygotic twins resembled one another more than dizygotic twins on all subscales of these measures, and the greater similarity was statistically significant for most of the subscales. This suggests that there may be a genetic influence on affect, which is expressed through both the frequency of engagement in and the emotional response to mood-related events. The results are discussed in the context of studies of genetic influences on subclinical levels of depression and other emotions.     

Development of Force Adaptation During Childhood

Humans learn to make reaching movements in novel dynamic environments by acquiring an internal motor model of their limb dynamics. Here, the authors investigated how 4- to 11-year-old children (N = 39) and adults (N = 7) adapted to changes in arm dynamics, and they examined whether those data support the view that the human brain acquires inverse dynamics models (IDM) during development. While external damping forces were applied, the children learned to perform goal-directed forearm flexion movements. After changes in damping, all children showed kinematic aftereffects indicative of a neural controller that still attempted to compensate the no longer existing damping force. With increasing age, the number of trials toward complete adaptation decreased. When damping was present, forearm paths were most perturbed and most variable in the youngest children but were improved in the older children. The findings indicate that the neural representations of limb dynamics are less precise in children and less stable in time than those of adults. Such controller instability might be a primary cause of the high kinematic variability observed in many motor tasks during childhood. Finally, the young children were not able to update those models at the same rate as the older children, who, in turn, adapted more slowly than adults. In conclusion, the ability to adapt to unknown forces is a developmental achievement. The present results are consistent with the view that the acquisition and modification of internal models of the limb dynamics form the basis of that adaptive process.     

New and Expanded Concepts in Neurophysiology,Psychology, and Sociology Complementary to Llorens' Developmental Theory: Achieving Growth and Development through Occupation for Neonatal Infants and their Families

ABSTRACT

Introduction: This issue expands the Llorens’ Developmental Theory of Occupational Therapy. Llorens drew from multiple theorists from the disciplines of sociology, neurophysiology, biology, ecology, psychology, occupational science, and psychodynamics to provide the profession of occupational therapy with a unified theory to facilitate growth and development for people of all ages—from infancy to old age.

Purpose: The purpose of this issue is to analyze, synthesize, and evaluate the continued relevance of Llorens' theory. In addition, the author evaluates, recommends, and applies updated theoretical premises in the realms of psychodynamics, neurophysiology, contextual ecology, and cognitive science that reflect the relevance of occupational therapy practice for infants and their families in the neonatal intensive care unit.

New Psychological Elements: Through the appropriate use of purposeful occupational activity and affective object relationships, the expanded Developmental Theory of Occupational Therapy provides a unified theory of occupation enablement as intrinsic spatiotemporal adaptation and as extrinsic socio ? cultural and physically contextual occupational adaptation to achieve growth and development across the lifespan.     

Examining the pathways between gratitude and self-rated physical health across adulthood

The current study examined whether dispositional gratitude predicts physical health among adults, and if so, whether this relationship occurs because grateful individuals lead healthier lives, either psychologically or physically. Specifically, we examined whether psychological health, healthy activities, and willingness to seek help for health concerns mediated the link between gratitude and self-reported physical health, as well as if these mediational pathways are moderated by age, in a broad sample of Swiss adults (N = 962, M_age = 52 years, age range: 19–84). Dispositional gratitude correlated positively with self-reported physical health, and this link was mediated by psychological health, healthy activities, and willingness to seek help for health concerns. However, the indirect effects for psychological health and healthy activities were stronger for older than younger adults. In other words, the mechanisms explaining why gratitude predicts health appear to differ across adulthood.