Robust tests of equivalence for k independent groups

A common question of interest to researchers in psychology is the equivalence of two or more groups. Failure to reject the null hypothesis of traditional hypothesis tests such as the ANOVA F‐test (i.e., H₀: μ₁ = … = μ_k) does not imply the equivalence of the population means. Researchers interested in determining the equivalence of k independent groups should apply a one‐way test of equivalence (e.g., Wellek, 2003). The goals of this study were to investigate the robustness of the one‐way Wellek test of equivalence to violations of homogeneity of variance assumption, and compare the Type I error rates and power of the Wellek test with a heteroscedastic version which was based on the logic of the one‐way Welch (1951) F‐test. The results indicate that the proposed Wellek–Welch test was insensitive to violations of the homogeneity of variance assumption, whereas the original Wellek test was not appropriate when the population variances were not equal.     

Therapeutic outcomes in the Welsh Government's school‐based counselling strategy: An evaluation

Aims: The purpose of this study was to evaluate the outcomes of school‐based counselling, as delivered in the Welsh Government's School‐based Counselling Strategy, for reducing psychological distress in young people aged 11–18. Method: The study used a quantitative cohort design, comparing levels of distress on either the Young Person's CORE (YP‐CORE) or the Strengths and Difficulties Questionnaire (SDQ) from baseline to endpoint. Data were available on 3613 episodes of counselling, across 42 datasets. Meta‐analytical procedures were used to identify the mean effect size and predictors of outcomes. Results: Within each dataset, counselling was associated with significant reductions in psychological distress, with a mean effect size (d) of 0.93(95% CI = 0.89–0.97) using a fixed effects model and 1.09 (95% CI = 0.97–1.22) using a random effects model. Datasets using the YP‐CORE had larger effect sizes than those using the SDQ, and datasets with more complete response rates had lower outcomes than those with poorer response rates. Conclusion: The results confirm that school‐based counselling, as delivered in the UK, is associated with significant reductions in psychological distress, comparable to adult counselling and psychotherapy services.     

Invited Address at the Occasion of the Bertelson Award 2005 Impairments in visual discrimination in amnesia: Implications for theories of the role of medial temporal lobe regions in human memory

A prominent and long-standing view of human long-term memory is that structures within the medial temporal lobe (MTL) work together to support the acquisition of memory for facts and events. In contrast to this view, recent studies in rats and non-human primates suggest dissociations in function between regions comprising the MTL. Evidence in support of such specialisation in humans, however, has been inconclusive, leading some researchers to propose that human MTL functions as a unitary system uniquely specialised for the acquisition and storage of long-term memory. This paper reviews some of the key studies from the animal and human literature that support an account of functional differentiation and discusses the different theoretical positions that have emerged from their findings. A series of recent experiments in humans designed to determine whether there is functional homogeneity in MTL regions across species are also reviewed and an alternative account of human memory—in which long-term memory is dependent upon representations distributed throughout the human brain rather than one specialised system—is proposed.     

The Effects of a Racist Act and Public Counter-Demonstrations on Race-Related Behavioral Intentions: A Natural Experiment

This study reports on a natural experiment that yielded information about the effects of a racist act and public counter-demonstrations on behavioral intentions. The conditions for this natural experiment arose when an act of racial hostility occurred at a small liberal-arts college in the northeastern United States. This event occurred approximately midway through data collection for a study comparing public and private behavioral intentions to donate money to African American interest groups. This coincidence afforded the opportunity to examine the effects of such events on members of the affected community. The results of this natural experiment show that both public and private expression of support for African American interest groups increased after the incident and ensuing demonstrations.     

The face of fear: Effects of eye gaze and emotion on visual attention

We investigated whether a fearful expression enhances the effect of another's gaze in directing the attention of an observer. Participants viewed photographs of faces whose gaze was directed ahead, to the left or to the right. Target letters then appeared unpredictably to the left or right. As expected, targets in the location indicated by gaze were detected more rapidly. In nonanxious volunteers the effects of fearful gaze did not differ from neutral gaze, but fearful expression had a more powerful influence in a selected high anxious group. Attention is thus more likely to be guided by the direction of fearful than neutral gaze, but only in anxiety-prone individuals.     

Economics Weak and Strong: Ecological Economics and Human Survival

Mounting evidence suggests that the human impact on the planet is reaching the point where the Earth's ecosystems will not be able to support the level of human occupation. The global economy also seems to be generating income disparities that threaten the social stability of even the most developed economies. Although both these trends are rooted in the operation of the global market economy, standard economics has surprisingly little to offer in the way of policies that might allow us to survive the twenty-first century with our current social and environmental systems intact. This article examines our current predicament from the point of view of neoclassical welfare economics and the alternative framework of ecological economics. We argue that ecological economics, by placing the study of economics squarely within human society and ecosystems, can lead the way to make economics both scientifically credible and policy relevant.     

Evaluative Conditioning: Arti-fact or -fiction?-A Reply to Baeyens, De Houwer, Vansteenwegen, and Eelen (1998)

Baeyenset al.(1998) claim that Field and Davey's (1997) controversial study of conceptual conditioning offers little threat to current conceptions of evaluative conditioning. This article addresses some of the questions posed by Baeyenset al.First, some criticisms of the conceptual conditioning study appear to be based on a misunderstanding of the procedure. Second, we address the issues surrounding the so-called Type-X procedure. Specifically, we begin by reviewing the status of studies that have used a procedure different from the Type-X procedure. It is then argued that, although the Type-X procedure has been used in only a portion of EC research, it has been used primarily in those studies whose outcome has been used to argue that evaluative conditioning (EC) is functionally distinct from autonomic conditioning. We then review the evidence from non-Type-X procedures that EC is a distinct form of learning. Finally, an attempt is made to explain why between-subject controls should be used as a matter of course in this field of research.