Estimation and visualization of confusability matrices from adaptive measurement data

We present a simple but effective method based on Luce’s choice axiom [Luce, R.D. (1959). Individual choice behavior: A theoretical analysis. New York: John Wiley & Sons] for consistent estimation of the pairwise confusabilities of items in a multiple-choice recognition task with arbitrarily chosen choice-sets. The method combines the exact (non-asymptotic) Bayesian way of assessing uncertainty with the unbiasedness emphasized in the classical frequentist approach.We apply the method to data collected using an adaptive computer game designed for prevention of reading disability. A player’s estimated confusability of phonemes (or more accurately, phoneme-grapheme connections) and larger units of language is visualized in an easily understood way with color cues and explicit indication of the accuracy of the estimates. Visualization of learning-related changes in the player’s performance is considered.The empirical validity of the choice axiom is evaluated using the game data itself. The axiom appears to hold reasonably well although a small systematic violation is observable for the smallest choice-set sizes.     

A Bayesian-optimal principle for learner-friendly adaptation in learning games

Adaptive learning games should provide opportunities for the student to learn as well as motivate playing until goals have been reached. In this paper, we give a mathematically rigorous treatment of the problem in the framework of Bayesian decision theory. To quantify the opportunities for learning, we assume that the learning tasks that yield the most information about the current skills of the student, while being desirable for measurement in their own right, would also be among those that are efficient for learning. Indeed, optimization of the expected information gain appears to naturally avoid tasks that are exceedingly demanding or exceedingly easy as their results are predictable and thus uninformative. Still, tasks that are efficient for learning may be experienced as too challenging, and the resulting failures can lower motivation. Therefore, in addition to quantifying the expected informational benefit for learning of any prospective task to be presented next, we also model the expected motivational cost of its presentation, measured simply as the estimated probability of failure in our example model. We propose a “learner-friendly” adaptation algorithm that chooses the learning tasks by optimizing the expected benefit divided by the expected cost. We apply this algorithm to a Rasch-like student model implemented within a real-world application and present initial results of a pilot experiment.     

Gender differences in distributive negotiation: When in the negotiation process do the differences occur?

This study tested whether the degree of association among aspiration level, intended opening offer, actual first offer, actual counter‐offer, and final agreement was moderated by negotiator gender. Results show that gender does moderate the association between the predictor variable of intended opening offer and the criterion variable of actual first offer and the relationship between intended opening offer and actual counter‐offer. Interesting, this latter association was statistically non‐significant for women and statistically significant for men. These results suggest that gender differences disadvantaging women seem to manifest with the actual first offer and the actual counter‐offer. Copyright © 2009 John Wiley & Sons, Ltd.     

Influence of properties of layered silicate minerals on adsorbed DNA surface affinity,self-assembly and nanopatterning

We report on the specific interaction between DNA and some mica-family minerals and other layered silicate structures. The interaction depends on mineral surface's crystallography, chemistry and potential. These properties are responsible for a remarkable variety of adsorption mechanisms and can be used to modulate surface self-assembly and nanopatterning of DNA. The controlled deposition of DNA onto non-conductive mineral regions with atomically flat boundaries has very attractive applications in nano-biotechnology (for example, microelectronics, microarrays and sensors). In addition, the extreme affinity discovered for some mineral surfaces, together with their ability to organize the DNA molecules, could be an indication of their catalytic potential. It may also have had relevance in the prebiotic environment, with important implications for the earth and life sciences.     

Modeling the Dynamics of Risky Choice

Individuals make decisions under uncertainty every day. Decisions are based on incomplete information concerning the potential outcome or the predicted likelihood with which events occur. In addition, individuals' choices often deviate from the rational or mathematically objective solution. Accordingly, the dynamics of human decision making are difficult to capture using conventional, linear mathematical models. Here, we present data from a 2-choice task with variable risk between sure loss and risky loss to illustrate how a simple nonlinear dynamical system can be employed to capture the dynamics of human decision making under uncertainty (i.e., multistability, bifurcations). We test the feasibility of this model quantitatively and demonstrate how the model can account for up to 86% of the observed choice behavior. The implications of using dynamical models for explaining the nonlinear complexities of human decision making are discussed as well as the degree to which the theory of nonlinear dynamical systems might offer an alternative framework for understanding human decision making processes.     

Reducing prejudice via direct and extended cross-group friendship

One of the most exciting developments in intergroup contact theory is the idea that a certain type of contact, cross-group friendship, might be particularly effective at reducing prejudice. In this chapter we review research on two types of cross-group friendship. Direct cross-group friendship refers to friendships that develop between members of different groups. Extended cross-group friendship, on the other hand, refers to vicarious experience of cross-group friendship, the mere knowledge that other ingroup members have cross-group friends. We consider the relationship between both types of cross-group friendship and prejudice and the processes that mediate and moderate these relationships. The research highlights the respective strengths and weaknesses of direct and extended cross-group friendship and illustrates how they might be practically combined in efforts to improve intergroup relations.     

Age Discrimination in the Evaluation of Job Applicants

This study investigated the nature of age discrimination against older job applicants. One hundred fifty‐six participants (102 students; 54 organization based) evaluated a hypothetical job applicant's (aged 33–66 years) work‐related competences and likelihood of being hired. Applicant age affected hiring decisions for both samples where there was a preference for hiring applicants aged 42–48 years. Applicants at both the older and younger ends of the continuum were less likely to be hired, with the oldest applicants (over 54 years) being the least likely to be hired. Although the applicants' age negatively affected evaluations of their trainability and sociability, the effect of applicant age on hiring evaluations was not mediated by these work‐related competencies, suggesting that age discrimination occurs via direct bias against older workers.