The Werther effect and assisted suicide

In the course of a large epidemiological study in the region of Basle, Switzerland, from 1992 to 1996, a considerable rise in suicides assisted by the right-to-die society EXIT was uncovered after wide press coverage of an assisted double suicide of a prominent couple in that region in March 1995. Further investigation revealed that the rise of assisted suicides for a period of 2 years after the critical event was statistically significant compared to the 2 years previous to the double suicide. This was especially true for women older than 65 years. Hence, the almost enthusiastic kind of reporting about this event was apt to induce imitation suicides or a "Werther-effect."     

Semantic categorization in the human brain: spatiotemporal dynamics revealed by magnetoencephalography

We examined the cortical representation of semantic categorization using magnetic source imaging in a task that revealed both dissociations among superordinate categories and associations among different base-level concepts within these categories. Around 200 ms after stimulus onset, the spatiotemporal correlation of brain activity elicited by base-level concepts was greater within than across superordinate categories in the right temporal lobe. Unsupervised clustering of data showed similar categorization between 210 and 450 ms mainly in the left hemisphere. This pattern suggests that well-defined semantic categories are represented in spatially distinct, macroscopically separable neural networks, independent of physical stimulus properties. In contrast, a broader, task-required categorization (natural/man-made) was not evident in our data. The perceptual dynamics of the categorization process is initially evident in the extrastriate areas of the right hemisphere; this activation is followed by higher-level activity along the ventral processing stream, implicating primarily the left temporal lobe.     

Potenzen und Grenzen einer allgemeinen Psychotherapietheorie

Ohne Zusammenfassung     

A Uniform Approach for Characterizing the Provably Total Number-Theoretic Functions of KPM and (Some of) its Subsystems

In this article we show how to extract with the use of the Buchholz-Cichon-Weiermann approach to subrecursive hierarchies from Rathjen's 1991 ordinal analysis of KPM a characterization of the provably total number-theoretic functions of KPM and some of its (most prominent) subsystems in a uniform and direct way.     

Motivational reserve: motivation-related occupational abilities and risk of mild cognitive impairment and Alzheimer disease

Midlife motivational abilities, that is, skills to initiate and persevere in the implementation of goals, have been related to mental and physical health, but their association with risk of mild cognitive impairment (MCI) and Alzheimer's disease (AD) has not yet been directly investigated. This relation was examined with data from the German Study on Ageing, Cognition, and Dementia in Primary Care Patients (AgeCoDe). A total of 3,327 nondemented participants (50.3% of a randomly selected sample) aged 75-89 years were recruited in primary care and followed up twice (after 1.5 and 3 years). Motivation-related occupational abilities were estimated on the basis of the main occupation (assessed at follow-up II) using the Occupational Information Network (O* NET) database, which provides detailed information on worker characteristics and abilities. Cox proportional hazards models were used to evaluate the relative risk of developing MCI and AD in relation to motivation-related occupational abilities, adjusting for various covariates. Over the 3 years of follow-up, 15.2% participants developed MCI and 3.0% developed AD. In a fully adjusted model, motivation-related occupational abilities were found to be associated with a reduced risk of MCI (HR: 0.77; 95% CI: 0.64-0.92). Motivation-related occupational abilities were associated with reduced risk of AD in ApoE ε4 carriers (HR: 0.48; CI: 0.25-0.91), but not in noncarriers (HR: 0.99; CI: 0.65-1.53). These results suggest that midlife motivational abilities are associated with reduced risk of MCI in general and with reduced risk of AD in ApoE ε4 carriers. Revealing the mechanisms underlying this association may inform novel prevention strategies for decelerating cognitive decline in old age.     

Predicting elections from the most important issue: A test of the take‐the‐best heuristic

We used the take‐the‐best heuristic to develop a model to forecast the popular two‐party vote shares in U.S. presidential elections. The model draws upon information about how voters expect the candidates to deal with the most important issue facing the country. We used cross‐validation to calculate a total of 1000 out‐of‐sample forecasts, one for each of the last 100 days of the ten U.S. presidential elections from 1972 to 2008. Ninety‐seven per cent of forecasts correctly predicted the winner of the popular vote. The model forecasts were competitive compared to forecasts from methods that incorporate substantially more information (e.g., econometric models and the Iowa Electronic Markets). The purpose of the model is to provide fast advice on which issues candidates should stress in their campaign. Copyright © 2010 John Wiley & Sons, Ltd.     

Knowing when to move on: cognitive and perceptual decisions in time

We investigated people's ability to decide how much time to spend on the task at hand. To make such decisions well, one must take into account, among other things, the cost of failing and how one's task performance changes as a function of time. We first investigated timing decisions when the underlying task was perceptual. Decisions were highly efficient and suggested that people can make good use of perceptual knowledge and abstract reward information. Previous studies have found that perceptual decisions are generally optimal, but that cognitive decisions are generally suboptimal--a perception-cognition gap. Does a similar gap exist for timing decisions? We compared timing decisions for a perceptual task with timing decisions for more cognitive tasks. Performance was highly similar across the tasks, which suggests that knowledge can be acquired, and used to make timing decisions, in an equally efficient way regardless of whether that knowledge is derived through perceptual or cognitive experience.     

“Man's best friend:” How the presence of a dog reduces mental distress after social exclusion

A substantial amount of research shows that social exclusion is a threat to mental health. In the research reported here, we tested the hypothesis that the presence of a companion animal can serve as a buffer against these adverse effects. In a controlled laboratory experiment, we found that only socially excluded participants who did not work in the presence of a dog reported lower mental well-being compared with socially excluded participants who performed in the presence of a dog and participants who were not socially excluded. The theoretical and practical implications of these findings are discussed.