Risk and Prisoner's Dilemma: A Reinterpretation of Coombs' Re‐parameterization

We propose a model to measure risk in a prisoner's dilemma based on Coombs' (1973) re‐parameterization of the game as an individual risk decision‐making task that chooses between a gamble of cooperation and another gamble of defection. Specifically, we propose an index, r, to represent the risk associated with cooperation relative to defection. In conjunction with Rapoport's (1967) index of cooperation (K), our formulation of risk allows us to construct games that vary in risk (as indexed by r) while controlling for cooperativeness (as indexed by K). Following utility analysis that models risk seeking as a convex utility function and risk averse as a concave function, we predict that risk‐seeking people cooperate more in games that the cooperation choice is more risky, whereas risk‐averse people cooperate more in games that the cooperation choice is less risky. In the three studies that we varied game parameters, used different measures of risk orientation and prosocial orientation and used different experimental procedures, we found robust results supporting our predictions. Theoretical analysis of our formulation further suggests that risk and cooperativeness of a prisoner's dilemma game is not entirely independent. Games that have a higher cooperativeness index are necessarily more risky. Copyright © 2011 John Wiley & Sons, Ltd.     

Multiple aspects in the sense of agency

Recent significant research in a number of disciplines centers on the concept of the sense of agency. Because many of these studies cut across disciplinary lines there is good reason to seek a clear consensus on what ‘sense of agency’ means. In this paper I indicate some complexities that this consensus might have to deal with. I also highlight an important phenomenological distinction that needs to be considered in any discussion of the sense of agency, regardless of how it gets defined. Finally, I suggest that the sense of agency has an ambiguous phenomenology and I offer some critical comments on current models that fail to notice this ambiguity.     

个体对效价预期和风险评估的时程加工机制:来自ERP的证据

采用事件相关电位技术(ERP),通过简单赌博任务,操纵结果预期的效价(输或赢)与风险(高风险与低风险),考察了个体对结果预期阶段的效价和风险评估的脑内时程动态加工过程。脑电结果发现:(1)在N2成分上,结果预期的效价主效应显著,预期输比预期赢能够引起更大的N2波幅;结果预期的风险主效应不显著。(2)在N500成分上,效价与风险之间的交互作用边缘显著,进一步简单效应分析发现,在预期输的条件下,肯定会输的N500波幅显著大于可能会输;而在预期赢的条件下,肯定会赢与可能会赢之间的N500波幅差异不显著。这说明,在不确定决策过程中的结果预期阶段,个体可能先对结果预期的效价进行加工,然后再对风险进行评估。     

But I can’t pass that far! The influence of motor skill on decision making

Objectives

The influence of motor skill on perceptual-cognitive and perceptual-motor decision making has been theorised but not verified empirically.

Method

Expert (n = 19), developmental (n = 20), and lesser-skilled netballers (n = 19) completed tests designed to evaluate three different components of domain-specific expertise: (i) motor skill-execution; (ii) perceptual-cognitive decision making; and (iii) perceptual-motor decision making.

Results

Each of the three measures was found to improve commensurate with domain-specific skill. Decisions requiring movements (perceptual-motor) elicited more accurate decision making than simple verbal responses (perceptual-cognitive), irrespective of participant skill. Although motor skill was found to be related to the successful execution of a most appropriate movement in a game situation, it was not found to limit the nature of the decision made by participants. No evidence was found to support the supposition that lesser-skilled participants bias their perceptual-cognitive decisions towards ones supported by their motor ability.

Conclusions

Results fail to comprehensively support the contemporary models for the development of perceptual-cognitive and perceptual-motor skill in sport.     

Effects of text messaged self-monitoring on class attendance and punctuality of at-risk college student athletes

This study examined the effects of text messaging class arrival to an academic counselor on the attendance and punctuality of 4 college student athletes. Each participant had a history of class tardiness and was considered to be at risk for academic failure. Class attendance and punctuality improved for all participants.     

Israeli Students' Perspectives Concerning Determinants of Intelligence

Abstract

Students' attitudes toward the nature versus nurture controversy pertaining to a variety of critical phenomena in the intelligence domain were assessed. A student inventory was constructed, pretested, and group administered to 269 students in various academic institutions in northern Israel, and comparisons were made between various sex, social, and ethnic groups. The majority of the students maintained that environment is the main factor influencing both personality and intelligence. Environment and an Environment x Heredity interaction were the most popular categories used to explain various generalizations about differences in ability, particularly among lower-class students. Students of Western origin were more inclined to adopt an environmental perspective on differences in IQ than were their Eastern counterparts. No sex differences were observed.     

Stopping speech suppresses the task-irrelevant hand

Some situations require one to quickly stop an initiated response. Recent evidence suggests that rapid stopping engages a mechanism that has diffuse effects on the motor system. For example, stopping the hand dampens the excitability of the task-irrelevant leg. However, it is unclear whether this ‘global suppression’ could apply across wider motor modalities. Here we tested whether stopping speech leads to suppression of the task-irrelevant hand. We used Transcranial Magnetic Stimulation over the primary motor cortex with concurrent electromyography from the hand. We found that when speech was successfully stopped the motor evoked potential from the task-irrelevant hand was significantly reduced compared to when the participant failed to stop speaking, or responded on non stop signal trials, or compared to baseline. This shows that when speech is quickly stopped, there is a broad suppression across the motor system. This has implications for the neural basis of speech control and stuttering.     

One hand, two objects: emergence of affordance in contexts

Studies on affordances typically focus on single objects. We investigated whether affordances are modulated by the context, defined by the relation between two objects and a hand. Participants were presented with pictures displaying two manipulable objects linked by a functional (knife-butter), a spatial (knife-coffee mug), or by no relation. They responded by pressing a key whether the objects were related or not. To determine if observing other's actions and understanding their goals would facilitate judgments, a hand was: (a) displayed near the objects; (b) grasping an object to use it; (c) grasping an object to manipulate/move it; (d) no hand was displayed. RTs were faster when objects were functionally rather than spatially related. Manipulation postures were the slowest in the functional context and functional postures were inhibited in the spatial context, probably due to mismatch between the inferred goal and the context. The absence of this interaction with foot responses instead of hands in Experiment 2 suggests that effects are due to motor simulation rather than to associations between context and hand-postures.     

The cost of action miscues: hemispheric asymmetries

Adaptive behaviors require preparation and when necessary inhibition or alteration of actions. The right hemisphere has been posited to be dominant for preparatory motor activation. This experiment was designed to learn if there are hemispheric asymmetries in the control of altered plans of actions. Cues, both valid and invalid, which indicate the hand most likely to be called onto respond, as well as the imperative stimuli that indicate the actual response hand, were presented to either the right or left visual fields of 14 normal right handed participants. The delay after a miscue is dependent on the time taken to inhibit the premotor and motor systems of the incorrectly activated hemisphere, as well as to activate the motor systems of the opposite hemisphere, which might have been interhemispherically inhibited by this miscue. Analyses of reaction times revealed that miscues presented in left hemispace (right hemisphere) cost more time than those miscues presented in right hemispace (left hemisphere), suggesting that activation of the preparatory systems controlled by the right hemisphere may take longer to reverse than those controlled by the left hemisphere. This asymmetry may be related to asymmetries in the strength of hemispheric activation with contralateral inhibition.     

Perceived Stress and Comorbid Illness Predict Depressive Symptomatology in People with Coeliac Disease

A high prevalence of depression is found in people with coeliac disease (CD). People with CD who are depressed are less likely to manage their illness effectively, which may lead to complications. Identification of variables associated with depression in people with CD may facilitate early detection and intervention. Participants were 749 members (125 males, 622 females) of the Queensland Coeliac Society (aged 18–88 years), recruited via a mailout. Participants completed the Modified Zung Self‐Rating Depression Scale, the Perceived Stress Scale, and the Perceived Consequences Subscale (from the Revised Illness Perception Questionnaire). Stress (p = .001) and comorbid medical illness (p = .01) were significantly associated with depression in CD. The current study made an original contribution to the body of literature by identifying stress and comorbid medical illness as predictors of depression in CD.