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.     

Philosophy and Science Dialogue: Free Will

In this dialogue Derk Pereboom and Marcel Brass discuss the free will problem from the perspective of philosophy and cognitive neuroscience. First, they give their opinion on how the two disciplines contribute to the free will problem. While Pereboom is optimistic regarding the contribution of science, Brass is more pessimistic and questions the usefulness of an empirical approach to the question whether free will exists or not. Then they outline their position on the free will problem. The idea of a transcendental agent is discussed in more detail. Furthermore, it is discussed whether free will scepticism is a politically, socially, psychologically viable position. Pereboom argues that promoting the idea of free will scepticism can have a positive impact on retributive emotions and the political practice regarding retributive punishment. Brass argues that retributive emotions are deeply rooted in evolution and therefore difficult to change via high-level beliefs about free will. Finally, the future of the free will debate is discussed. Both agree that the dialogue between philosophy and psychology should be intensified. Philosophy can benefit from taking empirical research more seriously. Psychology and neuroscience can benefit from philosophy by appreciating the sophistication and conceptual clarity of the philosophical debate. Both have to find a common language and define common problems that can be tackled from both perspectives.     

Experimental study of the differential effects of playing versus watching violent video games on children's aggressive behavior

There is great concern about the effects of playing violent video games on aggressive behavior. The present experimental study was aimed at investigating the differential effects of actively playing vs. passively watching the same violent video game on subsequent aggressive behavior. Fifty-seven children aged 10-13 either played a violent video game (active violent condition), watched the same violent video game (passive violent condition), or played a non-violent video game (active non-violent condition). Aggression was measured through peer nominations of real-life aggressive incidents during a free play session at school. After the active participation of actually playing the violent video game, boys behaved more aggressively than did the boys in the passive game condition. For girls, game condition was not related to aggression. These findings indicate that, specifically for boys, playing a violent video game should lead to more aggression than watching television violence.     

Emotions evoked by the sound of music: characterization, classification, and measurement

One reason for the universal appeal of music lies in the emotional rewards that music offers to its listeners. But what makes these rewards so special? The authors addressed this question by progressively characterizing music-induced emotions in 4 interrelated studies. Studies 1 and 2 (n=354) were conducted to compile a list of music-relevant emotion terms and to study the frequency of both felt and perceived emotions across 5 groups of listeners with distinct music preferences. Emotional responses varied greatly according to musical genre and type of response (felt vs. perceived). Study 3 (n=801)--a field study carried out during a music festival--examined the structure of music-induced emotions via confirmatory factor analysis of emotion ratings, resulting in a 9-factorial model of music-induced emotions. Study 4 (n=238) replicated this model and found that it accounted for music-elicited emotions better than the basic emotion and dimensional emotion models. A domain-specific device to measure musically induced emotions is introduced--the Geneva Emotional Music Scale.     

Methodological and empirical issues when dissociating cue-related from task-related processes in the explicit task-cuing procedure

In the explicit cuing version of the task-switching paradigm, each individual task is indicated by a unique task cue. Consequently, a task switch is accompanied by a cue switch. Recently, it has been proposed that priming of cue encoding contributes to the empirically observed switch costs. This proposal was experimentally supported by using a 2:1 mapping of cues to tasks, so that a cue switch does not necessarily imply a task switch. The results indeed suggested a substantial contribution of “cue-switch costs” to task-switch costs. Here we argue that the 2:1 mapping potentially leads to an underestimation of “pure” task-switch costs. To support this argument, we report the results of a new study in which we used “transition cues” that indicate the identity of the current task based on the identity of the preceding task. This new type of cue allows a full factorial manipulation of cue switches and task switches because it includes the condition in which a cue repetition can also indicate a task switch (i.e., when the “switch” cue is repeated). We discuss the methodological implications and argue that the present approach has merits relative to the previously used 2:1 mapping of cues to tasks.     

Psychological strain and emotional labor among police-officers: A diary study

The authors examined the relationship between psychological strain, emotional dissonance and emotional job demands during a working day of 65 Dutch (military) police officers, using a 5-day diary design. We hypothesized that emotional dissonance partly mediated the relationship between psychological strain at the start and at the end of a work shift. We also tested the mediating role of emotional dissonance between emotional job demands and psychological strain at the end of a work shift. Results of structural equation modeling analyses showed that psychological strain at the start of a work shift had a positive effect on the experience of emotional dissonance and psychological strain at the end of a work shift. Emotional dissonance partly mediated the relationship between psychological strain at the start and psychological strain at the end of a work shift. Results are discussed in light of conservation of resources theory (Hobfoll, S. E. (1988). The ecology of stress. New York: Hemisphere Publishing Corporation).     

Selective attention and threat: quick orienting versus slow disengagement and two versions of the dot probe task

The dot probe task is often used to assess attentional bias in anxiety, but some aspects need clarification. First, the results, which are traditionally summarized in an attentional bias index, do not allow for distinguishing between different selective attention processes; orienting and disengagement. Second, different versions of the dot probe task have been used with unknown relative merits. Participants (N=133) completed two versions of the dot probe task: the detection task (i.e. is there a probe?) and the differentiation task (i.e. what sort of probe is it?). The analysis carried out allowed for a differentiation between orienting and disengagement. The main finding was that trait anxiety is related to disengagement difficulties and not to speed of orienting. Concerning the relative merits of the two dot probe task versions, the results suggest that the detection task may be superior to the differentiation task. Implications for past and future research are discussed.