Differential access to information and anticipated group interaction: impact on individual reasoning

Two studies examined the impact of relative differences in access to information and anticipated group interaction on individual reasoning. On 2 different reasoning tasks (P. C. Wason's [1966] selection task and D. Kahneman & A. Tversky's [1973] lawyer-engineer problem), participants sensing that they knew more in anticipation of group interaction or knew less when not anticipating interaction were less susceptible to typical cognitive biases demonstrated by these tasks. Study 2 also showed that the effect of these social contexts was contingent on the task presentation format. Thus, knowing more in anticipation of group interaction and knowing less when not anticipating group interaction seemingly compensated for task features that enhance suboptimal reasoning strategies. These results illustrate the importance of the social context in which reasoning is situated and are discussed in terms of cognitive tuning, social comparison, and social motivations.     

Historical change of suicide seasonality in the canton of zurich, Switzerland

Current research is yielding an increasingly heterogeneous picture of suicide seasonalities: They seem to depend on methods and, moreover, they seem to have smoothed in recent decades. This work examines the latter issue by comparing suicide seasonalities in the canton of Zurich, Switzerland, in the 16 th -18 th centuries, 1901-1920 and 1969-94. The results indicate shifts of peaks and lows on suicide seasonalities over the centuries, with a smoothing of seasonalities toward the 21 th century. The recent period does not show any suicide seasonality at all. The canton of Zurich seems to be ahead of the general trend found in other regions of Switzerland.     

Erroneous Perceptions in Generating Sequences of Random Events1

This paper reports the results of 2 studies that examine the perceptions of individuals attempting to generate random sequences. It was hypothesized that erroneous perceptions dominate probability judgment. The first study demonstrated that subjects verbalized significantly more erroneous than accurate perceptions when generating sequences of random binary events. The second study was designed both to replicate these data and to assess the role of motivation on the frequency of misconceptions. Results showed that the total number of erroneous perceptions again outnumbered accurate perceptions but, motivation did not increase the number of misconceptions. A basic error concerned subjects' inability to consider events as being independent of each other. The theoretical and practical implications of these results are discussed in relation to the psychology of gambling.     

Diagrams in the theory of differential equations (eighteenth to nineteenth centuries)

Diagrams have played an important role throughout the entire history of differential equations. Geometrical intuition, visual thinking, experimentation on diagrams, conceptions of algorithms and instruments to construct these diagrams, heuristic proofs based on diagrams, have interacted with the development of analytical abstract theories. We aim to analyze these interactions during the two centuries the classical theory of differential equations was developed. They are intimately connected to the difficulties faced in defining what the solution of a differential equation is and in describing the global behavior of such a solution.     

The P3 component of the ERP reflects conscious perception, not confidence

Consistent with numerous electrophysiological studies, we recently reported that conscious perception is associated with a widely distributed modulation of the P3 component (Lamy, Salti, & Bar-Haim, 2009). We also showed that correct objective performance in the absence of subjective awareness is associated with a spatially more restricted modulation of the P3. The relatively late occurrence of the P3 along with lack of control for post-perceptual processes suggests that this component might reflect processes related to stimulus evaluation or confidence rather than to visual awareness or objective performance. The main aim of the current study was to test this hypothesis. While EEG was recorded, participants performed a forced-choice localization task and reported their subjective perception of the target on a 3-level scale that also indexed their confidence. The results showed that our previous findings are replicated when confidence is controlled for.     

The Development of Adolescent Generalized Anxiety and Depressive Symptoms in the Context of Adolescent Mood Variability and Parent-Adolescent Negative Interactions

This study explored the influence of adolescent mood variability on the symptom development of generalized anxiety and depression in the context of parent-adolescent negative interactions. Participants were 456 adolescents (55.7 % male) from a community sample, who were followed from age 13 to 16 years. During 4 annual assessments, adolescents reported on their generalized anxiety and depressive symptoms, and both parents and adolescents on levels of negative interactions with each other. Within each study year, adolescents rated their daily mood states during 5 consecutive days for 3 times per year (total of 9 weeks). The absolute differences between mood states on consecutive days were summed to construct a mood variability score. Results showed that high levels of adolescent mood variability predicted increases in generalized anxiety and depressive symptoms across the studied period. No influence of negative interactions on anxiety and depression development was found, but positive predictive links from mood variability to negative interactions at age 14 and 15 appeared. The study underscores the role of adolescent mood variability in the development of symptoms of generalized anxiety and depression during adolescence, but found little evidence for an influence of parent-adolescent negative interactions on internalizing problem development.     

The stability of a double-slab configuration of two-phase particles confined in a third phase

The stability of a double-slab configuration of two-phase particles confined in a third phase is studied as a function of shape in two and three dimensions. The condition of stability against splitting one phase in the particle into two separate identical slabs is shown to be the sum of the wetting factor and the change in the interface area relative to the shape of the two-phase particle. It is found that the double-slab configuration can be stable for a wide range of wetting factors and shapes.