Inverse association between dopaminergic neurotransmission and Iowa Gambling Task performance in pathological gamblers and healthy controls

Linnet, J., Møller, A., Peterson, E., Gjedde, A. & Doudet, D. (2011). Inverse association between dopaminergic neurotransmission and Iowa Gambling Task performance in pathological gamblers and healthy controls. Scandinavian Journal of Psychology 52, 28–34. The dopamine system is believed to affect gambling behavior in pathological gambling. Particularly, dopamine release in the ventral striatum appears to affect decision‐making in the disorder. This study investigated dopamine release in the ventral striatum in relation to gambling performance on the Iowa Gambling Task (IGT) in 16 Pathological Gamblers (PG) and 14 Healthy Controls (HC). We used Positron Emission Tomography (PET) to measure the binding potential of [¹¹C] raclopride to dopamine D2/3 receptors during a baseline and gambling condition. We hypothesized that decreased raclopride binding potentials in the ventral striatum during gambling (indicating dopamine release) would be associated with higher IGT performance in Healthy Controls, but lower IGT performance in Pathological Gamblers. The results showed that Pathological Gamblers with dopamine release in the ventral striatum had significantly lower IGT performance than Healthy Controls. Furthermore, dopamine release was associated with significantly higher IGT performance in Healthy Controls and significantly lower IGT performance in Pathological Gamblers. The results suggest that dopamine release is involved both in adaptive and maladaptive decision‐making. These findings may contribute to a better understanding of dopaminergic dysfunctions in pathological gambling and substance related addictions.     

Indecisiveness: Specificity and predictive validity

This study investigated the specificity of indecisiveness compared to trait anxiety. In addition, the predictive validity of indecisiveness for postdecisional problems with regard to choosing a major was examined. A sample of 539 adolescents participated at the beginning of Grade 12 and was followed until the first year in higher education. Factor analyses showed evidence for a differentiation between indecisiveness and trait anxiety. In addition, indecisiveness at the beginning of Grade 12 predicted less commitment to the choice of a major in higher education, which, in turn, predicted less choice stability. The effect of indecisiveness on these postdecisional problems remained significant after controlling for trait anxiety, providing further evidence for the specificity of indecisiveness. Copyright © 2010 John Wiley & Sons, Ltd.     

Contextual modulation of reading rate for direct versus indirect speech quotations

In human communication, direct speech (e.g., Mary said: “I’m hungry”) is perceived to be more vivid than indirect speech (e.g., Mary said [that] she was hungry). However, the processing consequences of this distinction are largely unclear. In two experiments, participants were asked to either orally (Experiment 1) or silently (Experiment 2, eye-tracking) read written stories that contained either a direct speech or an indirect speech quotation. The context preceding those quotations described a situation that implied either a fast-speaking or a slow-speaking quoted protagonist. It was found that this context manipulation affected reading rates (in both oral and silent reading) for direct speech quotations, but not for indirect speech quotations. This suggests that readers are more likely to engage in perceptual simulations of the reported speech act when reading direct speech as opposed to meaning-equivalent indirect speech quotations, as part of a more vivid representation of the former.     

Perceptual training strongly improves visual motion perception in schizophrenia

Schizophrenia patients exhibit perceptual and cognitive deficits, including in visual motion processing. Given that cognitive systems depend upon perceptual inputs, improving patients’ perceptual abilities may be an effective means of cognitive intervention. In healthy people, motion perception can be enhanced through perceptual learning, but it is unknown whether this perceptual plasticity remains in schizophrenia patients. The present study examined the degree to which patients’ performance on visual motion discrimination can be improved, using a perceptual learning procedure. While both schizophrenia patients and healthy controls showed decreased direction discrimination thresholds (improved performance) with training, the magnitude of the improvement was greater in patients (47% improvement) than in controls (21% improvement). Both groups also improved moderately but non-significantly on an untrained task—speed discrimination. The large perceptual training effect in patients on the trained task suggests that perceptual plasticity is robust in schizophrenia and can be applied to develop bottom-up behavioral interventions.     

A quantum probability account of order effects in inference

Order of information plays a crucial role in the process of updating beliefs across time. In fact, the presence of order effects makes a classical or Bayesian approach to inference difficult. As a result, the existing models of inference, such as the belief-adjustment model, merely provide an ad hoc explanation for these effects. We postulate a quantum inference model for order effects based on the axiomatic principles of quantum probability theory. The quantum inference model explains order effects by transforming a state vector with different sequences of operators for different orderings of information. We demonstrate this process by fitting the quantum model to data collected in a medical diagnostic task and a jury decision-making task. To further test the quantum inference model, a new jury decision-making experiment is developed. Using the results of this experiment, we compare the quantum inference model with two versions of the belief-adjustment model, the adding model and the averaging model. We show that both the quantum model and the adding model provide good fits to the data. To distinguish the quantum model from the adding model, we develop a new experiment involving extreme evidence. The results from this new experiment suggest that the adding model faces limitations when accounting for tasks involving extreme evidence, whereas the quantum inference model does not. Ultimately, we argue that the quantum model provides a more coherent account for order effects that was not possible before.     

Computational explorations of perceptual symbol systems theory

The aim of this paper is twofold. First, we provide a methodological pathway from theories of situated, embodied cognition to simulations with an eye to empirical evidence, and suggest a possible cross-fertilization between cognitive robotics and psychology. Psychological theories, in particular those formulated at an abstract level, include models which are often severely underspecified at the level of mechanisms. This is true in the synchronic, constructive perspective (how can the effects observed in experiments be concretely generated by the model's mechanisms?) and in the diachronic, developmental perspective (how can such mechanisms be learned and developed?). The synthetic method of artificial cognitive systems research, and in particular of cognitive robotics, can complement research in psychology (and neurosciences) by exploring the constructive and developmental aspects of theories. Our second aim is to provide an example of such a methodology by describing simulations aiming at developing a perceptual symbol system (PSS) (Barsalou, 1999). We then describe the two main theoretical constructs of the PSS, perceptual symbols and simulators, illustrate their development in an artificial system, and test the system in prediction, categorization, and abstraction tasks.     

Bringing ethics into focus: How regulatory focus and risk preferences influence (Un)ethical behavior

In four laboratory studies, we find that regulatory focus induced by situational cues (such as the framing of an unrelated task) or primed influences people’s likelihood to cross ethical boundaries. A promotion focus leads individuals to be more likely to act unethically than a prevention focus (Studies 1, 2, and 3). These higher levels of dishonesty are explained by the influence of a person’s induced regulatory focus on his or her behavior toward risk. A promotion focus leads to risk-seeking behaviors, while a prevention focus leads to risk avoidance (Study 3). Through higher levels of dishonesty, promotion focus also results in higher levels of virtuous behavior (Studies 2 and 3), thus providing evidence for compensatory ethics. Our results also demonstrate that the framing of ethics (e.g., through an organization’s ethics code) influences individuals’ ethical behavior and does so differently depending on an individual’s induced regulatory focus (Study 4).     

Egocentric or allocentric frameworks for the evaluation of other people's reachability

The adoption of egocentric and allocentric frameworks in the perception of other people’s reachability was investigated. In study 1, 24 adults (12 experienced and 12 inexperienced dealing with children) judged vertical reachability for themselves and for two children. In study 2, 37 parents judged vertical reachability for themselves and their children. Absolute errors (|estimate-actual reachability|), absolute percent errors (|1-judgement/actual reachability| × 100), and error tendency (underestimations, right judgments, or overestimations) were calculated. Adults were quite accurate in perceiving their own reachability (absolute percent errors ranging from 2.20% in study 1 to 3.12% in study 2) and clearly less precise when estimating children’s reachability. Results indicated a tendency for adults to overestimate reachability of the younger child (study 1) and a tendency for parents to overestimate their children’s reachability (study 2). No correlation between judgement errors for the self and for the children in any of the studies was observed. Results support the existence of an allocentric and not an egocentric framework when evaluating other people’s affordances.     

Individual differences in need for cognition and decision making in the Iowa Gambling Task

Differences in decision making between individuals differing in Need for Cognition (NFC) are examined using the Iowa Gambling Task (IGT). Previous work using normative one time decisions suggests that individual low in NFC process gains and losses differently than those high in NFC and are more susceptible to decision biases. The IGT is a popular laboratory task that involves making risky decisions from experience involving both gains and losses. In the first experiment, low NFC participants performed significantly worse than the high NFC participants. A second experiment designed to examine the nature of these differences provides evidence that low NFC participants place more importance on gains as opposed to losses when performing the IGT. Results are discussed in light of previous work suggesting that low NFC participants place more importance on losses in mixed outcome decisions.     

临床决策中患者及其家属的地位与作用

医生、医院每天都在为患者做临床决策。而在各个决策中患者与家属应该处于什么地位的问题早有争论。除了疾病外患者性别、年龄、家庭、经济、社会地位的个体差异决定了医生决策的不同。患者要真正参与,就必须真正全面知情。关于患者参与多少的问题要因人而异,可能只是提出意愿,可能提出耗资的底线,可能权衡费效比,可能以生活质量为唯一原则。总之,临床决策中患者及其家属的地位因人而异。