Causes of Allais common consequence paradoxes: An experimental dissection

The common consequence paradox of Allais can be decomposed into three simpler principles: transitivity, coalescing, and restricted branch independence. Different theories attribute such paradoxes to violations of restricted branch independence only, to coalescing only, or to both. This study separates tests of these two properties in order to compare these theories. Although rank-dependent utility (RDU) theories, including cumulative prospect theory (CPT), violate branch independence, the empirical pattern of violations is opposite that required by RDU theories to account for Allais paradoxes. Data also show systematic violations of coalescing, which refute RDU theories. The findings contradict both original and CPTs with or without their editing principles of combination and cancellation. Modal choices were well predicted by Birnbaum's RAM and TAX models with parameters estimated from previous data. The effects of event framing on these tests were also assessed and found to be negligible.     

The repeated insertion model for rankings: Missing link between two subset choice models

Several probabilistic models for subset choice have been proposed in the literature, for example, to explain approval voting data. We show that Marley et al.'s latent scale model is subsumed by Falmagne and Regenwetter's size-independent model, in the sense that every choice probability distribution generated by the former can also be explained by the latter. Our proof relies on the construction of a probabilistic ranking model which we label the repeated insertion model. This model is a special case of Marden's orthogonal contrast model class and, in turn, includes the classical Mallows -model as a special case. We explore its basic properties as well as its relationship to Fligner and Verducci's multistage ranking model.The authors are grateful to the National Science Foundation for grants SES98-18756 to Regenwetter and Peke, and SBR97-30076 to Regenwetter. This collaborative research was carried out in the context of the conference Random Utility 2000 held at Duke University and sponsored by NSF, the Fuqua School of Business and the Center for International Business Education and Research. We thank the editor and four referees for helpful suggestions and we are grateful to Prof. J. I. Marden for providing useful information on contrast models. We thank Moon-Ho Ho for programming and running the data analyses.     

Hemispheric specialization and independence for word recognition: a comparison of three computational models

Two findings serve as the hallmark for hemispheric specialization during lateralized lexical decision. First is an overall word advantage, with words being recognized more quickly and accurately than non-words (the effect being stronger in response latency). Second, a right visual field advantage is observed for words, with little or no hemispheric differences in the ability to identify non-words. Several theories have been proposed to account for this difference in word and non-word recognition, some by suggesting dual routes of lexical access and others by incorporating separate, and potentially independent, word and non-word detection mechanisms. We compare three previously proposed cognitive theories of hemispheric interactions (callosal relay, direct access, and cooperative hemispheres) through neural network modeling, with each network incorporating different means of interhemispheric communication. When parameters were varied to simulate left hemisphere specialization for lexical decision, only the cooperative hemispheres model showed both a consistent left hemisphere advantage for word recognition but not non-word recognition, as well as an overall word advantage. These results support the theory that neural representations of words are more strongly established in the left hemisphere through prior learning, despite open communication between the hemispheres during both learning and recall.     

Conflict of interest in Croatia: doctors with dual obligations

There is an emerging awareness of the possibility of conflicts of interest in the practice of medicine in Croatia. The paper examines areas within the medical profession where conflicts of interest can and have occurred, probably not only in Croatia. Particularly addressed are situations when a doctor may have dual obligations and how independent ethics committees can help in decreasing the influence of a conflict of interest. The paper also presents extracts from the Croatian Code of Ethics for the medical profession that address problems of conflict of interest. An earlier version of this paper entitled was presented at an International Conference on “Conflict of Interest and its Significance in Science and Medicine” held in Warsaw, Poland on 5–6 April, 2002.     

Editorial independence at medical journals owned by professional associations: A survey of editors

The purpose of this study was to assess the degree of editorial independence at a sample of medical journals and the relationship between the journals and their owners. We surveyed the editors of 33 medical journals owned by not-for-profit organizations (“associations”), including 10 journals represented on the International Committee of Medical Journal Editors (nine of which are general medical journals) and a random sample of 23 specialist journals with high impact factors that are indexed by the Institute for Scientific Information. The main outcome measures were the authority to hire, fire, and oversee the work of the editor; the editor’s tenure and financial compensation; control of the journal’s budget; publication of material about the association; and the editor’s perceptions about editorial independence and pressure over editorial content. Of the 33 editors, 23 (70%) reported having complete editorial freedom, and the remainder reported a high level of freedom (a score of ≥8, where 10 equals complete editorial freedom and 1 equals no editorial freedom). Nevertheless, a substantial minority of editors reported having received at least some pressure in recent years over editorial content from the association’s leadership (42%), senior staff (30%), or rank-and-file members (39%). The association’s board of directors has the authority to hire (48%) or fire (55%) the editor for about half of the journals, and the editor reports to the board for 10 journals (30%). Twenty-three editors (70%) are appointed for a specific term (median term =5 years). Three-fifths of the journals have no control over their profit, and the majority of journals use the association’s legal counsel and/or media relations staff. Stronger safeguards are needed to give editors protection against pressure over editorial content, including written guarantees of editorial freedom and governance structures that support those guarantees. Strong safeguards are also needed because editors may have less freedom than they believe (especially if they have not yet tested their freedom in an area of controversy).     

Empirical indistinguishability: From the knowledge structure to the skills

Recent literature has pointed out that the basic local independence model (BLIM) when applied to some specific instances of knowledge structures presents identifiability issues. Furthermore, it has been shown that for such instances the model presents a stronger form of unidentifiability named empirical indistinguishability, which leads to the fact that the existence of certain knowledge states in such structures cannot be empirically tested. In this article the notion of indistinguishability is extended to skill maps and, more generally, to the competence-based knowledge space theory. Theoretical results are provided showing that skill maps can be empirically indistinguishable from one another. The most relevant consequence of this is that for some skills there is no empirical evidence to establish their existence. This result is strictly related to the type of probabilistic model investigated, which is essentially the BLIM. Alternative models may exist or can be developed in knowledge space theory for which this indistinguishability problem disappears.     

Don’t look back in anger: A cross-sectional and dyadic examination of the Dark Triad,anger, and aggression in athletes

ObjectivesThe Dark Triad (psychopathy, Machiavellianism, and narcissism) has been linked to anti-social behaviour in sport, and while anti-social behaviour often involves aggression and violence, no research to date has examined the relationship between the Dark Triad and anger and aggression in athletes. The current two-sample study sought to address this gap.DesignMulti-sample cross-sectional design.MethodSample 1 included 224 athletes (M_AGE = 23.85) and Sample 2 included 98 coach-athlete dyads (196 total; athlete M_AGE = 18.15, coaches M_AGE = 34.84). In both samples, facets of the Dark Triad were related to anger and aggression.ResultsIn Sample 1, regression analyses indicated that psychopathy positively predicted both anger and aggression and Machiavellianism positively predicted aggression. In Sample 2, actor-partner interdependence models indicated a combination of dyadic relationships (i.e., both actor [coach and athlete personality predicted their own anger and aggression] and partner effects [coach and athlete personality predicted the other’s anger and aggression]). In this regard, actor effects were found between psychopathy and both anger and aggression and narcissism and aggression. Coach to athlete partner effects were found for narcissism and anger and Machiavellianism and aggression.ConclusionsOverall, the findings provide evidence for personal and interpersonal relationships between the Dark Triad and anger and aggression and highlight the potential for the darker side of both athlete and coach personality to influence athlete emotions.     

The independence of positive and negative affect depends on the affect measure

This study examined the degree of independence between Positive Affect (PA) and Negative Affect (NA) within a given situation. The affective state was measured before and after an experimentally induced success or failure experience in an anagram task. Two types of affect measures were used to assess PA and NA: the Positive and Negative Affect Schedule (PANAS) and a Pleasantness-Unpleasantness scale. Consistent with our hypotheses, results show that PA and NA are independent when measured with the PANAS but are correlated when assessed with the other scale. These PA-NA correlations differed significantly from each other before and after emotion induction, respectively. Additional analyses indicate that both PA scales are differentially sensitive to the mood induction procedure. The findings are discussed with respect to circumplex models of emotion.     

Discriminative stimulus control and the effects of concurrent operants.

Discriminative-stimulus-control functions were investigated in a concurrent operant context. Variable-interval reinforcement schedules were arranged for pigeons on two response keys. One key, illuminated with a white vertical line on green background (position irrelevant), was programmed with a given schedule value across groups. For different groups of pigeons, the alternative key, illuminated with green alone, was programmed with twice, the same, or half the reinforcement frequency of the other key. Stimulus-control gradients were collected from both keys as line orientation was varied. On the green-plus-line alternative, flattest gradients were observed when twice the reinforcement frequency was concurrently programmed and the steepest were observed when equal values were concurrently programmed. Also examined were the effects of a programmed changeover delay, important in maintaining the independence of concurrent operants. The changeover delay was found to have relatively minor effects upon stimulus control, despite its typical and marked effects upon steady-state responding.     

An incomplete data approach to the analysis of covariance structures

In this paper, linear structural equation models with latent variables are considered. It is shown how many common models arise from incomplete observation of a relatively simple system. Subclasses of models with conditional independence interpretations are also discussed. Using an incomplete data point of view, the relationships between the incomplete and complete data likelihoods, assuming normality, are highlighted. For computing maximum likelihood estimates, the EM algorithm and alternatives are surveyed. For the alternative algorithms, simplified expressions for computing function values and derivatives are given. Likelihood ratio tests based on complete and incomplete data are related, and an example on using their relationship to improve the fit of a model is given.This research forms part of the author's doctoral thesis and was supported by a Commonwealth Postgraduate Research Award. The author also wishes to acknowledge the support of CSIRO during the preparation of this paper and the referees' comments which led to substantial improvements.