The existential assumptions of traditional logic

There have been and continue to be disagreements about how to consider the traditional square of opposition and the traditional inferences of obversion, conversion, contraposition and inversion from the perspective of contemporary quantificational logic. Philosophers have made many different attempts to save traditional inferences that are invalid when they involve empty classes. I survey some of these attempts and argue that the only satisfactory way of saving all the traditional inferences is to make the existential assumption that both the subject and predicate classes and their complement classes are non-empty for all the propositions we admit. I briefly indicate the room for continued controversy over how properly to interpret Aristotle’s statements regarding these inferences, but find some plausibility in the views of Manley Thompson and A.N.Prior that Aristotle had in mind a particular arrangement of existential import unfamiliar to most contemporary logicians     

When sanctions fail to increase cooperation in social dilemmas: considering the presence of an alternative option to defect

Previous social dilemma research has shown that sanctioning defection may enhance cooperation. The authors argue that this finding may have resulted from restricting participants to two behaviors (cooperation and defection). In this article, the authors introduce the concept of a "social trilemma" (a social dilemma in which an alternative option to defect is present) and tested the effect of a sanction. The authors show that a sanction only increased cooperation and collective interests in the traditional social dilemma. In a social trilemma, the sanction failed because it caused some people to choose the alternative option to defect. Moreover, the results indicate that this was especially the case when people did not expect fellow group members to cooperate. In this case, the sanction even worked counterproductive because it decreased collective interests. It is concluded that allowing individuals to consider alternative options to defect can reveal the potential detrimental effects of sanctioning systems for the collective.     

Evaluating expectations about negative emotional states of aggressive boys using Bayesian model selection

Researchers often have expectations about the research outcomes in regard to inequality constraints between, e.g., group means. Consider the example of researchers who investigated the effects of inducing a negative emotional state in aggressive boys. It was expected that highly aggressive boys would, on average, score higher on aggressive responses toward other peers than moderately aggressive boys, who would in turn score higher than nonaggressive boys. In most cases, null hypothesis testing is used to evaluate such hypotheses. We show, however, that hypotheses formulated using inequality constraints between the group means are generally not evaluated properly. The wrong hypotheses are tested, i.e.. the null hypothesis that group means are equal. In this article, we propose an innovative solution to these above-mentioned issues using Bayesian model selection, which we illustrate using a case study.     

Effects of Vocabulary and Phonotactic Probability on 2-Year-Olds’ Nonword Repetition

This study investigates the relationship between nonword repetition (NWR) and vocabulary in 2-year-olds. Questions addressed are whether (1) NWR and vocabulary are associated, (2) phonotactic probability affects NWR, and (3) there is an interaction effect between phonotactic probability and vocabulary on NWR performance. The general aim of the study is to investigate whether NWR, as a task of phonological storage, assesses the quality of phonological representations in children as young as 2 years of age. 557 Dutch 2-year-olds performed a NWR task containing items of varying phonotactic probability as well as a receptive vocabulary task. The results showed a moderate, significant correlation between NWR and vocabulary. Phonotactic probability had an effect on NWR performance. Further analyses showed that there was a significant interaction between phonotactic probability and vocabulary for part of the items. These results support previously reported effects of vocabulary and phonotactic probability on NWR in older, English-speaking children for a large sample of Dutch-speaking 2-year-olds, and provide evidence that NWR assesses the quality of phonological representations already in very young children.     

In search of reflective behavior and shared understanding in ad hoc expert teams.

The work reported on here concentrates on virtual ad hoc expert teams for the integration of learning and working, as ad hoc teams seem to be one way to cope with complexity in a knowledge-intensive society. In order to let ad hoc teams learn and work together, group members require effective communication and shared understanding among each other. Two empirical studies were conducted to study collaborative learning and shared understanding, one exploratory study and one experiment. In the first study, it was explored how virtual design teams work and learn together. Based on conceptual ideas, collaborative learning and shared understanding were observed and assessed in a design team over a period of four months. It was concluded that shared understanding was suboptimal; mainly due to the effect that hardly any questions were raised and answered. The second study elaborates on the need to encourage question-answer patterns and reflective behavior in such teams. A tool was developed that supported questioning behavior. As it was hypothesized that this tool leads to better questioning behavior, which in turn results in more reflective behavior and in increased shared understanding, an experiment was conducted. In the exploratory study, as well as in the experimental study, the perceived shared understanding increased over time. However, in both studies suboptimal questioning behavior and little reflective activity were noticed. The main results of the two empirical studies are compared and discussed.     

Interelectrode distance and warning signal interval and the evaluation of clinical electrical shock

Contingent shock is used on a small scale for behaviors that may lead to severe damages to one's body or to others. Research efforts focus on exploring variables that control the evaluation of electrical shocks. This study focuses on two practical questions, that is, whether the distance between the electrodes would influence the evaluation of shock and whether using a variable time interval in the administration would influence the evaluation of shock. Results reveal that both investigated variables control the evaluation of shock. Multiple shocks appear to produce a stronger sensation than single shocks, a phenomenon that was also revealed in previous studies. Copyright © 2009 John Wiley & Sons, Ltd.