Laypeople do use sample variance: The effect of embedding data in a variance-implying story

When using sample data to decide whether two populations differ, laypeople attend to the difference between group means, but largely overlook within-group variability (Obrecht, Chapman, & Gelman, 2007 Obrecht, N. A., Chapman, G. B. and Gelman, R. 2007. Intuitive t-tests: Lay use of statistical information. Psychonomic Bulletin & Review, 14: 1147–1152.  [Google Scholar]). We show, first, that laypeople know about and use story-implied variability when making pairwise comparisons. Then we demonstrate that participants’ sensitivity to variance in a dataset is boosted when presented in a context that implies consistent variance information. Statistical data were couched in stories about electrical conductivity measurements obtained from element samples (low-variability category) or body weight measurements from samples of peoples (high-variability category). We manipulated, between participants, whether the data variance matched or mismatched the story-implied variability. Participants who received data in a matching context showed high sensitivity to variance, while those in the mismatching condition did not. Laypeople use statistical data to make reasonable inferences when those data are provided in a context that makes sense.     

Enhanced memory for emotional pictures: A product of increased attention to affective stimuli?

The current experiment addressed the question, is enhanced memory for emotional pictures due to increased attention to affective stimuli? Participants viewed pairs of pictures (emotional-neutral or neutral-neutral) whilst their eye movements were recorded; participants had to decide which picture out of each pair they preferred. There was increased attention to positive pictures and decreased attention to negative images during picture viewing. Despite this, when a recognition test was given 1 week later, memory enhancements were found for negative pictures only. Moreover, although there was a general correlation between total inspection time and memory performance, this reliability was clear only for neutral pictures, and not for emotional images. The results suggest that memory advantages for emotional pictures can occur without increased attention to such images.     

Understanding smoking after acute illness: An application of the sentinel event method

The sentinel event theory provides a stepwise approach for building models to understand how negative events can spark health behaviour change. This study tested a preliminary model using the sentinel events method in a sample (N = 300) of smokers who sought care for acute cardiac symptoms. Patients completed measures on: smoking-related causal attribution, perceived severity of the acute illness event, illness-related fear and intentions to quit smoking. Patients were followed up one week after the health event and a seven-day timeline follow back was completed to determine abstinence from tobacco. Structural equation models were performed using average predictor scale scores at baseline, as well as three different time anchors for ratings of illness severity and illness-related fear. Quit intentions, actual illness severity and age were the consistent, positive and independent predictors of seven-day point prevalence abstinence. Additional research on the influences of perceptions and emotional reactions is warranted.     

The impact of school connectedness on violent behavior, transport risk-taking behavior, and associated injuries in adolescence

Adolescents engage in many risk-taking behaviors that have the potential to lead to injury. The school environment has a significant role in shaping adolescent behavior, and this study aimed to provide additional information about the benefits associated with connectedness to school. Early adolescents aged 13 to 15 years (N = 509, 49% boys) were surveyed about school connectedness, engagement in transport and violence risk-taking, and injury experiences. Significant relations were found between school connectedness and reduced engagement in both transport and violence risk-taking, as well as fewer associated injuries. This study has implications for the area of risk-taking and injury prevention, as it suggests the potential for reducing adolescents' injury through school based interventions targeting school connectedness.     

Using session-by-session measurement to compare mechanisms of action for acceptance and commitment therapy and cognitive therapy

Debate continues about the extent to which postulated mechanisms of action of cognitive behavior therapies (CBT), including standard CBT (i.e., Beckian cognitive therapy [CT]) and acceptance and commitment therapy (ACT) are supported by mediational analyses. Moreover, the distinctiveness of CT and ACT has been called into question. One contributor to ongoing uncertainty in this arena is the lack of time-varying process data. In this study, 174 patients presenting to a university clinic with anxiety or depression who had been randomly assigned to receive either ACT or CT completed an assessment of theorized mediators and outcomes before each session. Hierarchical linear modeling of session-by-session data revealed that increased utilization of cognitive and affective change strategies relative to utilization of psychological acceptance strategies mediated outcome for CT, whereas for ACT the mediation effect was in the opposite direction. Decreases in self-reported dysfunctional thinking, cognitive "defusion" (the ability to see one's thoughts as mental events rather than necessarily as representations of reality), and willingness to engage in behavioral activity despite unpleasant thoughts or emotions were equivalent mediators across treatments. These results have potential implications for the theoretical arguments behind, and distinctiveness of, CT and ACT.