Participant recruitment methods and statistical reasoning performance

Optimal Bayesian reasoning performance has reportedly been elusive, and a variety of explanations have been suggested for this situation. In a series of experiments, it is demonstrated that these difficulties with replication can be accounted for by differences in participant-sampling methodologies. Specifically, the best performances are obtained with students from top-tier, national universities who were paid for their participation. Performance drops significantly as these conditions are altered regarding inducements (e.g., using unpaid participants) or participant source (e.g., using participants from a second-tier, regional university). Honours-programme undergraduates do better than regular undergraduates within the same university, paid participation creates superior performance, and top-tier university students do better than students from lower ranked universities. Pictorial representations (supplementing problem text) usually have a slight facilitative effect across these participant manipulations. These results indicate that studies should take account of these methodological details and focus more on relative levels of performance rather than absolute performance.     

Context and Prior Impression Effects on Attention, Judgment Standards, and Ratings: Contrast Effects Revisited

The present study extended research on contrast effects by (a) examining the effect of context performances on ratings of a target performance when a prior impression of the target performer already exists, and (b) clarifying the issue of whether contrast is caused by attention to context-discrepant behavior or shifts in judgment standards. The results demonstrated that the existence of a prior impression mitigates the influence of context performances on ratings. Judgment standards were found to be unstable and dependent on information provided to raters by the experimental manipulations. Regression analyses showed that both attention and standards of judgment mediate the relationship between context and ratings. Implications of these findings for contrast effects, performance ratings, and the importance of reliable judgment standards for real-world performance appraisals are discussed.     

Suicide reduction and prevention: strategies and interventions

This paper focuses on suicide reduction and prevention. It considers what the United Kingdom government and associated bodies such as Department of Health, the National Health Service and Prison Service could do and are considering doing to prevent suicide in Britain. UK suicide statistics for the period 1971 and 1997 are compared and the Highland Health Board suicide prevention strategy for the 1990s is considered. The articles in this symposium are introduced and the recent UK legal cases involving Ms B and Diane Pretty are included.

Counsellors and psychotherapists have always been concerned, to varying degrees, about clients committing or attempting suicide [1]. It is a topic which can trigger much concern and interest with both neophyte and experienced therapists [2]. In the past decade there has been a growth in individual membership of counselling and psychotherapeutic professional bodies with more therapists becoming accredited and/or registered as qualified practitioners. Thus there has been additional pressure on therapists to adhere to professional codes of practice and ethics.To take the correct action and to be seen to take the correct action within client-therapist relationships is now paramount. It could be argued that this has always been the case. However, therapists not working within a professional framework may have had less incentive to act in a professional manner. A proactive approach may be recommended when seeing clients with suicidal ideation and/or intention (Palmer, 1995). In these cases, inaction can sometimes prove fatal so it is incumbent upon the therapist to support and help the client through the difficult period (Curwen, 1997).     

The prevention of depressive symptoms in rural Australian women

Two interventions aimed at preventing depressive symptoms in women living in Western Australian rural communities were evaluated against a no‐intervention control condition. The standard intervention was based upon traditional cognitive‐behaviour treatments for depression; the experimental intervention was based upon prevention strategies derived from the learned helplessness model of depression (e.g. Peterson, Maier, & Seligman, 1993 ). Seventy‐six women were randomly assigned to either the standard or the experimental group, and a further 20 women formed a no‐intervention control group. The standard group showed a reduction in depressive symptoms at post‐test, but no effects at 6‐week or 6‐month follow‐ups. In contrast, a reduction in depressive symptoms did not appear for the experimental group until the 6‐week follow‐up at which time a less depressive attributional style was also evident; these effects were even more pronounced at the 6‐month follow‐up. The no‐intervention control group showed no changes across time. It is argued that these results support the applicability of prevention strategies based on the learned helplessness model to this population. Copyright © 2003 John Wiley & Sons, Ltd.     

Executive functions predict conceptual learning of science

We examined the relationship between executive functions and both factual and conceptual learning of science, specifically chemistry, in early adolescence. Sixty‐three pupils in their second year of secondary school (aged 12–13 years) participated. Pupils completed tasks of working memory (Spatial Working Memory), inhibition (Stop‐Signal), attention set‐shifting (ID/ED), and planning (Stockings of Cambridge), from the CANTAB. They also participated in a chemistry teaching session, practical, and assessment on the topic of acids and alkalis designed specifically for this study. Executive function data were related to (1) the chemistry assessment which included aspects of factual and conceptual learning and (2) a recent school science exam. Correlational analyses between executive functions and both the chemistry assessment and science grades revealed that science achievements were significantly correlated with working memory. Linear regression analysis revealed that visuospatial working memory ability was predictive of chemistry performance. Interestingly, this relationship was observed solely in relation to the conceptual learning condition of the assessment highlighting the role of executive functions in understanding and applying knowledge about what is learned within science teaching.     

Diagnostic Utility: Experimental Demonstrations and Replications of Powerful Question Effects in High‐Stakes Deception Detection

The concept of diagnostic utility was used to create questions that would differentially affect deception detection accuracy. Six deception detection studies show that subtle differences in questioning produced accuracy rates that were predictably, substantially, and reliably above and below chance. The first 3 detection studies demonstrate that diagnostically useful questioning can reliably achieve accuracy rates over 70% with student and experienced judges. The fourth and fifth experiments demonstrated negative diagnostic utility among federal investigators but not students. The final experiment crossed 3 sets of interview questions with experience. Strong question effects produced a swing in accuracy from 32 to 73%. A questioning by experience interaction was also obtained.     

Factorial design and covariance in the study of individual educational development

This is the report of the application of the principles of factorial design to an investigation of individual educational development. The specific type of factorial design formulated was a 2 × 3 × 3 × 3 arrangement, that is, the effect of sex, grade location, scholastic standing, and individual order, singly and in all possible combinations was studied in relation to educational development as measured by theIowa Tests of Educational Development. An application of the covariance method was introduced which resulted in increased precision of this type of experimental design by significantly reducing experimental error. The two concomitant measures used to increase the sensitiveness of the experiment were initial status of individual development and mental age. Without these statistical controls all main effects and two first-order interactions would have been accepted as significant. With their use only sex (doubtful), scholastic standing, and individual order demonstrated significant effects. The chief beauty of the analysis of variance and covariance as an integral part of a self-contained experiment is demonstrated in the complete single analysis of the data. The statistical utilization of the experimental results has also been developed for purposes of estimation and prediction. The mathematical statistician is being continuously required to develop and analyze experimental designs of increasing complexity since the introduction of the analysis of variance and covariance. The mathematical formulation and solution of the problem of this investigation is carried out. The methods illustrated and explained in this study, and modifications and extensions of them are capable of very wide application. The general principles can be used to various degrees and in a number of ways.For the research grant to finance this study, grateful acknowledgment is given to the Graduate School, the University of Minnesota.