Using the Gamma Generalized Linear Model for Modeling Continuous,Skewed and Heteroscedastic Outcomes in Psychology

Some researchers in psychology have ordinarily relied on traditional linear models when assessing the relationship between predictor(s) and a continuous outcome, even when the assumptions of the traditional model (e.g., normality, homoscedasticity) are not satisfied. Of those who abandon the traditional linear model, some opt for robust versions of the ANOVA and regression statistics that usually focus on relationships for the typical or average case instead of trying to model relationships for the full range of relevant cases. Generalized linear models, on the other hand, model the relationships among variables using all available and relevant data and can be appropriate under certain conditions of non-normality and heteroscedasticity. In this paper, we summarize the advantages and limitations of using generalized linear models with continuous outcomes and provide two simplified examples that highlight the methodology involved in selecting, comparing, and interpreting models for positively skewed outcomes and certain heteroscedastic relationships.     

Negative beliefs about low back pain are associated with persistent high intensity low back pain

While previous cross-sectional studies have found that negative beliefs about low back pain are associated with pain intensity, the relationship between back beliefs and persistent low back pain is not well understood. This cohort study aimed to examine the role of back beliefs in persistent low back pain in community-based individuals. A hundred and ninety-two participants from a previous musculoskeletal health study were invited to take part in a two-year follow-up study. Beliefs about back pain were assessed by the Back Beliefs Questionnaire (BBQ) at baseline and low back pain intensity was measured by the Chronic Pain Grade Questionnaire at baseline and follow-up. Of the 150 respondents (78.1%), 16 (10.7%) reported persistent high intensity low back pain, 12 (8.0%) developed high intensity low back pain, in 16 (10.7%) their high intensity low back pain resolved and 106 (70.7%) experienced no high intensity low back pain. While participants were generally positive about low back pain (BBQ mean (SD) = 30.2 (6.4)), those with persistent high intensity pain reported greater negativity (BBQ mean (SD) = 22.6 (4.9)). Negative beliefs about back pain were associated with persistent high intensity low back pain after adjusting for confounders (M (SE) = 23.5 (1.6) vs. >30.1 (1.7), p < .001). This study found negative back beliefs were associated with persistent high intensity low back pain over 2 years in community-based individuals. While further longitudinal studies are required, these findings suggest that targeting beliefs in programs designed to treat and prevent persistent high intensity low back pain may be important.     

Extending Traditional Psychological Disciplines to Positive Psychology: A View from Subjective Well-being

This article reviews how research from traditional psychological disciplines has been extended and applied to the area of positive psychology (PP), specifically in the area of subjective well-being (SWB). Moving from a universal to cultural perspective, then to a group, and finally an individual perspective, this article draws theories from evolutionary, cultural, social, and personality psychology. The evolutionary perspective that negative emotions (i.e. evolved psychological mechanisms) are an impediment to positive psychology’s goal of building positive experiences has been extended and modified. Research in PP now recognizes the pitfalls of excessive positive emotions and happiness, and how negative emotions can contribute to optimal human functioning. The cultural approach investigates cultural variations in conceptualizations of SWB and highlights that the benefits and detrimental effects of positive and negative emotions are not universal. Theories on social dynamics further our understanding of how evaluative judgments influence well-being, and address a fundamental question in PP: Is the goal of increasing people’s well-being viable? Finally, personality theories explain individual differences in well-being and the practice of PP. In sum, the recognition that PP encapsulates the negative, and growing awareness of the importance of culture, social context, and the individual, heralds the evolving conceptualization of PP.     

The cognitive locus of distraction by acoustic novelty in the cross-modal oddball task

Unexpected stimuli are often able to distract us away from a task at hand. The present study seeks to explore some of the mechanisms underpinning this phenomenon. Studies of involuntary attention capture using the oddball task have repeatedly shown that infrequent auditory changes in a series of otherwise repeating sounds trigger an automatic response to the novel or deviant stimulus. This attention capture has been shown to disrupt participants' behavioral performance in a primary task, even when distractors and targets are asynchronous and presented in distinct sensory modalities. This distraction effect is generally considered as a by-product of the capture of attention by the novel or deviant stimulus, but the exact cognitive locus of this effect and the interplay between attention capture and target processing has remained relatively ignored. The present study reports three behavioral experiments using a cross-modal oddball task to examine whether the distraction triggered by auditory novelty affects the processing of the target stimuli. Our results showed that variations in the demands placed on the visual analysis (Experiment 1) or categorical processing of the target (Experiment 2) did not impact on distraction. Instead, the cancellation of distraction by the presentation of an irrelevant visual stimulus presented immediately before the visual target (Experiment 3) suggested that distraction originated in the shifts of attention occurring between attention capture and the onset of the target processing. Possible accounts of these shifts are discussed.     

Incorporating family therapy into asthma group intervention: a randomized waitlist-controlled trial

Asthma psychoeducational programs have been found to be effective in terms of symptom-related outcome. They are mostly illness-focused, and pay minimal attention to systemic/familial factors. This study evaluated a novel asthma psychoeducation program that adopted a parallel group design and incorporated family therapy. A randomized waitlist-controlled crossover clinical trial design was adopted. Children with stable asthma and their parents were recruited from a pediatric chest clinic. Outcome measures included, for the patients: exhaled nitric oxide (eNO), spirometry, and adjustment to asthma; and for the parents: perceived efficacy in asthma management, Hospital Anxiety and Depression Scale anxiety subscale, Body Mind Spirit Well-being Inventory emotion subscale, and Short Form 12 health-related quality of life scale. Forty-six patients participated in the study. Attrition rates were 13.0% and 26.0% for the active and control groups, respectively. Repeated-measures ANOVA revealed a significant decrease in airway inflammation, as indicated by eNO levels, and an increase in patient's adjustment to asthma and parents' perceived efficacy in asthma management. Serial trend analysis revealed that most psychosocial measures continued to progress steadily after intervention. Significant improvements in both symptom-related measures and mental health and relationship measures were observed. The findings supported the value of incorporating family therapy into asthma psychoeducation programs.     

When Thinking Rationally Increases Biases: The Role of Rational Thinking Style in Escalation of Commitment

This paper reports three studies examining the relationship between the rational thinking style (RTS, i.e. individual differences in relying on a conscious, analytical, and relatively affect‐free information processing system) and decision quality in an escalation situation. In contrast to conventional wisdom that rational thinking increases decision quality, but consistent with the predictions derived from the cognitive dissonance theory, results of Studies 1 and 2 revealed that high scorers in Pacini and Epstein's (1999 ) rationality inventory were more likely to have escalation bias than were low scorers. The results further showed that only the ability component of rationality, not the engagement component, was positively correlated with escalating commitment. Similar patterns of results were obtained for situations when participants were personally responsible for prior decisions (Study 1) and when they were not (Study 2). Results of Study 3 showed that the underlying process responsible for the effect of RTS on the escalating tendency is that RTS increases beliefs in prior decisions, which in turn increases escalation. Implications for our understanding of escalation of commitment, rationality theory, and managerial practices are discussed. Cet article rend compte de 3 études examinant la relation entre le style de pensée rationnelle (RTS i.e. les différences individuelles reposent sur un système de traitement de l’information consciente, analytique et relativement libre d’affects) et la qualité de la décision dans une situation d’escalade d’engagement. Contrairement à l’opinion communément admise pour laquelle la pensée rationnelle accroît la qualité de la décision, mais consistante avec les prédictions découlant de la théorie de la dissonance cognitive, les résultats des études 1 et 2 indiquent que des personnes obtenant un score élevéà l’Inventaire Rationnel‐Expérientiel de Pacini et Esptein (1999) sont plus enclines à tomber dans le piège de l’escalade d’engagement que celles dont le score est bas. D’autres résultats montrent que la capacitéà la rationalité, non celle à l’engagement, est positivement corrélée avec l’escalade d’engagement. Des résultats semblables sont obtenus lors de situations où les participants sont personnellement responsables de leurs décisions antérieures (Etude 1) ou non (Etude 2). Les résultats de l’étude 3 montrent que le processus responsable de l’effet du RTS sur la tendance à s’engager est le suivant: il accroît les croyances dans les décisions antérieures qui augmentent à leur tour l’engagement. Ces résultats nous permettent de mieux comprendre l’escalade d’engagement, la théorie rationnelle et les pratiques managériales.     

Social Identity Theory: a critical synthesis of its bases, evidence and controversies

The social identity theory (SIT) and the self-categorization theory have had considerable influence on contemporary Social Psychology, making notable contributions to our understanding of the social dimension of behaviour. In the present work, we summarise the bases of these theories and critically review the most controversial elements of SIT, exploring its limits and potential. As shown here, the literature offers a heterogeneous body of research that includes outstanding efforts of synthesis and integration, but also numerous fragmentary studies and decontextualized interpretations that have generated distorted views of group behaviour. Taking into account the multidimensional, contextually mediated, dynamic and functional nature of identitary processes, which clearly emerge in the most serious works in the field, there is obviously a need to review the epistemological and methodological tools currently employed, with a view to developing practices that allow the study of group phenomena in a manner more suited to their complexity.     

Perceptions of social changes and social identity: Study focusing on Hong Kong society after reunification

Based on the social identity theory and the need for closure theory, the present study investigates how Hong Kong people's perceptions of social changes after the reunification with China are related to their social identities. A randomly selected sample of 315 Hong Kong residents participated in a telephone survey to report their perceptions of major changes in five social areas, as well as their social identities. A series of logistic regression analyses confirmed, as predicted, that the perceived pace of social change was related to the participants' preference for a single identity ('Hongkonger' or 'Chinese') over dual identities ('Hongkonger and Chinese', or 'Chinese and secondarily Hongkonger') through the mediation of social uncertainty. The results indicate that for individuals with dual social identities, perceptions and evaluations of social change are important factors contributing to social identity preference.     

Psychosocial Factors Predicting SARS-Preventive Behaviors in Four Major SARS-Affected Regions

This multinational study examined intended and actual adoption of SARS-preventive behaviors in major SARS-affected regions: Guangdong (China), Hong Kong, Singapore, and Toronto (Canada). The theory of reasoned action (TRA) and the theory of planned behavior (TPB) were adopted as theoretical frameworks. A measure was constructed to assess attitude, subjective norm, perceived behavioral control (PBC), knowledge of SARS, and SARS-preventive behaviors. Seventy-five working adults were recruited from each region. They completed the new measure in an initial study, and reported their actual behaviors 2 weeks later. Results provided cross-cultural generalizability of the TRA by showing that attitude and subject norm predicted SARS-preventive behaviors for all the groups. PBC was a statistically significant predictor for all participants except those from Guangdong, indicating that the TPB is applicable only to people from Hong Kong, Singapore, and Toronto. Knowledge of SARS also was found to be an independent predictor.