Evidence for rule-based processes in the inverse base-rate effect.

Three studies provide convergent evidence that the inverse base-rate effect (Medin & Edelson, 1988) is mediated by rule-based cognitive processes. Experiment 1 shows that, in contrast to adults, prior to the formal operational stage most children do not exhibit the inverse base-rate effect. Experiments 2 and 3 demonstrate that an adult sample is a mix of participants relying on associative processes who categorize according to the base-rate and participants relying on rule-based processes who exhibit a strong inverse base-rate effect. The distribution of the effect is bimodal, and removing participants independently classified as prone to rule-based processing effectively eliminates the inverse base-rate effect. The implications for current explanations of the inverse base-rate effect are discussed.     

Risk- and protective factors for memory plasticity in aging

ABSTRACT

Risk and protective factors for cognitive function in aging may affect how much individuals benefit from their environment or life experiences by preserving or improving cognitive abilities. We investigated the relations between such factors and outcome from episodic-memory training in 136 healthy young and older adults. Tested risk factors included carrying the ?4 variant of the apolipoprotein E allele (APOE), age, body mass index, blood pressure, and cholesterol. Protective factors included higher levels of education, intelligence quotient (IQ), physical activity, fatty acids, and vitamin D. Average increases in memory performance were seen after training, with ample variation between individuals. Being young, female, and having higher IQ were positive predictors of memory improvement. No other relationships were observed. Similar benefit was observed across APOE allelic variation. This indicates that beyond IQ, age, and sex, known risk -and protective factors of cognitive function in aging were not significantly related to memory plasticity.     

Mental health – a normal state?

ABSTRACT

How can we conceptualize mental health; what is the relation between mental health and normality; and what has psychoanalysis to say about these questions? After a short resume of the views concerning normality and melancholia in the last centuries, the author turns to Freud and Bion. For Freud, mental health at best seems to be a relatively mild neurotic state, and perfect mental health is an unattainable ideal. Bion underlines the dynamic nature of the concept; mental health comprehended as a process. Problems connected to the individual’s subjective view of his or her mental health are considered, and some consequences that the questions under discussion have for psychoanalytic treatment are discussed. The author concludes with a reflection on the complex relation between mental health and normality.     

A gentle reminder that mean does not imply modal behavior: Few are in-group biased in minimal groups

Previous research reports that people organized into newly formed, arbitrary groups (i.e., minimal groups) are on average in-group biased. However, that people on average behave in a certain way does not imply that most people behave that way. Here, I report four studies (n = 224) demonstrating in-group biased average behaviors driven by a minority of about 30% participants. Further, only 14% reported allocating resources in a group-biased manner because they “favored the in-group.” I investigate and discuss how methodological issues related to non-normally distributed data, not taking participants’ intentions into account, and using fixed response matrices can lead to overestimations of how widespread in-group bias is in minimal groups.