Crossed categorization and stereotyping: Structural analyses, effect patterns, and dissociative effects of context relevance

Based on the “Who said what?” paradigm, a new method is proposed for investigating social categorization and non-evaluative stereotype application in crossed categorization. The method is applied in 5 studies that manipulated relative context relevance of crossed age and gender categories. Social categorization is characterized by 2 indices: Relative subgroup memory assesses the amount of subgroup formation represented in memory, and relative category dominance the relative weight of each dimension of categorization. Both indices were affected by context relevance. There was strong evidence for social categorization at the subgroup level, whereas stereotype application followed a simple pattern of category dominance, in which only the context-relevant dimension exerted an effect. The results bear on current models of category-based impression formation and intergroup perception, and on category-activation cum stereotype-inhibition models.     

Proactive People Are Morning People1

Proactivity is the willingness and ability to take action to change a situation to one's advantage and has been studied in a wide range of contexts. The role of chronotype on proactivity has not been assessed. Individual differences in circadian rhythms have been widely acknowledged and are accepted as an interesting facet of human personality. Morning people were more proactive than evening types, and people with small differences in rise time between weekdays and free days were also more proactive persons. Sleep length (on weekdays and on free days) and total time spent in weekend oversleep did not show any relationship with proactivity. These results suggest that morning people are more proactive than are evening types.     

Practical Arguments for Theoretical Theses

Pascals wager is expounded as a paradigm case of a practical,decision-theoretical argument for acting as if a proposition is true when wehave no theoretical reasons to accept or reject it (1.1.–1.2.). Thoughthe paradigm is fallacious in various respects there are valid and adequatearguments for acting as if certain propositions are true: that theoreticalentities exist, that there are material perceptual objects, that the worldis uniform across time (1.3). After this analysis of examples the authorsgeneral approach for developing criteria for the validity and adequacy oftypes of argument (2.1.) is applied: Having discussed some problems(2.2.–2.3.), a general epistemic principle for such pascal argumentsis developed, which characterizes their premisses and, if introduced as anadditional premiss, can make them deductively valid (2.4).     

WHAT IT FEELS LIKE TO BE IN A SUPERPOSITION. AND WHY

This paper attempts an interpretation of Everett's relative state formulation of quantum mechanics that avoids the commitment to new metaphysical entities like worlds or minds. Starting from Everett's quantum mechanical model of an observer, it is argued that an observer's belief to be in an eigenstate of the measurement (corresponding to the observation of a well-defined measurement outcome) is consistent with the fact that she objectively is in a superposition of such states. Subjective states corresponding to such beliefs are constructed. From an analysis of these subjective states and their dynamics it is argued that Everett's pure wave mechanics is subjectively consistent with von Neumann's classical formulation of quantum mechanics. It follows from the argument that the objective state of a system is in principle unobservable. Nevertheless, an adequate concept of empirical reality can be constructed.     

Exact and best confidence intervals for the ability parameter of the Rasch model

A commonly used method to evaluate the accuracy of a measurement is to provide a confidence interval that contains the parameter of interest with a given high probability. Smallest exact confidence intervals for the ability parameter of the Rasch model are derived and compared to the traditional, asymptotically valid intervals based on the Fisher information. Tables of the exact confidence intervals, termed Clopper-Pearson intervals, can be routinely drawn up by applying a computer program designed by and obtainable from the author. These tables are particularly useful for tests of only moderate lengths where the asymptotic method does not provide valid confidence intervals.     

Contact-free measurement of heart rate, respiration rate, and body movements during sleep

We describe a noncontact method for the ambulant measurement of basic sleep physiology parameters in humans, particularly for field studies involving sleep research and sleep disturbances. This method traces the body movements, respiration, and heart action of a person at rest or asleep on a bed, using four high-resolution force sensors installed under the bedposts. The recoil movement of the body at each heartbeat, known as the cardioballistic effect, as well as the lifting and lowering of the thorax, while breathing, causes very small shifts of the center of gravity of the bed and the subject. These shifts are reflected in the altering force distributions across the four sensors. Cardiac and respiratory parameters and the subject’s movement activity can be calculated from the sensor signals. Neither electrodes nor other kinds of transducers are in direct contact with the subject, which is the main advantage of this technique over conventional methods. Laboratory experiments were carried out to estimate validity and practicability. The method has been found to be adequate, especially for automated and unattended sleep-data collection over long periods of time.     

Computer supported mathematics with Ωmega

Classical automated theorem proving of today is based on ingenious search techniques to find a proof for a given theorem in very large search spaces—often in the range of several billion clauses. But in spite of many successful attempts to prove even open mathematical problems automatically, their use in everyday mathematical practice is still limited.The shift from search based methods to more abstract planning techniques however opened up a paradigm for mathematical reasoning on a computer and several systems of that kind now employ a mix of interactive, search based as well as proof planning techniques.The Ωmega system is at the core of several related and well-integrated research projects of the Ωmega research group, whose aim is to develop system support for a working mathematician as well as a software engineer when employing formal methods for quality assurance. In particular, Ωmega supports proof development at a human-oriented abstract level of proof granularity. It is a modular system with a central proof data structure and several supplementary subsystems including automated deduction and computer algebra systems. Ωmega has many characteristics in common with systems like NuPrL, CoQ, Hol, Pvs, and Isabelle. However, it differs from these systems with respect to its focus on proof planning and in that respect it is more similar to the proof planning systems Clam and λClam at Edinburgh.