Using Latent Class Analysis to Model Temperament Types

Mixture models are appropriate for data that arise from a set of qualitatively different subpopulations. In this study, latent class analysis was applied to observational data from a laboratory assessment of infant temperament at four months of age. The EM algorithm was used to fit the models, and the Bayesian method of posterior predictive checks was used for model selection. Results show at least three types of infant temperament, with patterns consistent with those identified by previous researchers who classified the infants using a theoretically based system. Multiple imputation of group memberships is proposed as an alternative to assigning subjects to the latent class with maximum posterior probability in order to reflect variance due to uncertainty in the parameter estimation. Latent class membership at four months of age predicted longitudinal outcomes at four years of age. The example illustrates issues relevant to all mixture models, including estimation, multi-modality, model selection, and comparisons based on the latent group indicators.     

Care vs Food as an Emotional Regulation Strategy in Elementary School Children: The Role of the Attachment Style

Abstract

According to attachment theory, potentially threatening stimuli tend to activate the attachment system for the search of the protective figure. In secure attachments, the experience of responsive relationships increases the probability of resorting to available figures as a strategy for regulating emotions in stressful situations. The aim of the research was to verify whether, in conditions of mild threat, children’s attachment styles affect the choice between caring relationships and food as a form of emotion regulation. We used a mixed experimental design to perform this research. Here, we presented children (N?=?65; M_age= 9.4) with threatening and neutral images and, afterwards, asked them to select from images of caring relationship or images of food. The results indicate that securely and ambivalently attached but not avoidantly attached children under both the neutral and threatening image conditions chose the care pictures over the food pictures. Second, only the securely attached increased their choice of care over food images in the threatening condition, and third, this difference was significant when compared with the avoidant children. In conclusion, the results show that although in general the choice of care is primary with respect to food, children with insecure attachments differ from secure children between the two options of emotional regulation.     

'I'm Thinking'

This paper aims to show that the 'I'm thinking', to really be the awareness of an act of thought, must refer to or indicate particular thought-contents that are not actually being focused on in the consciousness. A consequence of this is that the 'I'm thinking' lacks the absolute incorrigibility necessary to justify its role as a premise for the cogito.     

A Theory of Physical Activity Maintenance

Regular physical activity is related to numerous psychological and physical benefits. Physical activity interventions have had varying degrees of success with adoption; however, maintenance over the long term is even more difficult to achieve, as the majority of individuals who start a physical activity program drop out or relapse. Although the physical activity maintenance literature is scant, there is evidence that the predictors of adoption are different from those of maintenance. Thus, it follows that physical activity adoption and maintenance require unique approaches. The explanatory power of such predictors, however, is limited by the absence of a cogent theoretical framework. Therefore, this paper presents the Physical Activity Maintenance (PAM) theory, which incorporates individual psychosocial variables (goal-setting, motivation, and self-efficacy), and contextual variables of the environment and life stress (triggers of relapse). Goal-setting is framed as satisfaction, attainment, and commitment; motivation as self-motivation and expectations; and self-efficacy as both barrier and relapse. The contextual variables may facilitate or impede physical activity maintenance directly and indirectly via the individual psychosocial variables. The PAM is presented to stimulate research on physical activity maintenance and advance our understanding of how and why people do and do not maintain physical activity long term.