Overcoming the winner's curse: an adaptive learning perspective

The winner's curse phenomenon refers to the fact that the winner in a common value auction, in order to actually win the auction, is likely to have overestimated the item's value and consequently is likely to gain less than expected and may even lose (i.e., it is said to be “cursed”). Past research, using the “Acquiring a company” task has shown that people do not overcome this bias even after they receive extensive feedback. We suggest that the persistence of the winner's curse is due to a combination of two factors: variability in the environment that leads to ambiguous feedback (i.e., choices and outcomes are only partially correlated) and the tendency of decision makers to learn adaptively. We show in an experiment that by reducing the variance in the feedback, performance can be significantly improved. Copyright © 2007 John Wiley & Sons, Ltd.     

Loss aversion,diminishing sensitivity,and the effect of experience on repeated decisions

Three experiments are presented that explore the assertion that loss aversion and diminishing sensitivity drive the effect of experience on choice behavior. The experiments are focused on repeated choice tasks where decision makers choose repeatedly between alternatives and get feedback after each choice. Experiments 1a and 1b show that behavioral tendencies that were previously interpreted as indications of loss aversion in decisions from experience are better described as products of diminishing sensitivity to absolute payoffs. Experiment 2 highlights a nominal magnitude effect: A decrease in the magnitude of the nominal payoffs eliminates the evidence for diminishing sensitivity. These and related previous results can be captured with a model that assumes reliance on small samples of subjective experiences, and an increase in diminishing sensitivity with payoff variability. Copyright © 2008 John Wiley & Sons, Ltd.     

AMPLE智力模型——PASS智力模型的扩展

本文根据实验事实,对PASS智力模型进行扩展,并提出一个简称AMPLE的智力模型。这个模型基于脑的四个功能系统学说,包括注意（attention）、操纵（manipulation）、计划（planning）、学习（learning）和评估（evaluation）等过程。它是一个囊括觉、知、情、意诸成分在内的全面的智力模型。     

相关维度数量对两种结构类别学习的影响

在多重系统理论研究基础上,运用即时反馈训练范式,以大学生为被试,考查相关维度数量对基于规则和信息整合两种结构的类别学习的影响.结果表明:(1)相关维度数量是影响类别学习的重要因素,基于规则单维度结构的学习显著优于信息整合结构和基于规则双维度结构的学习,基于规则双维度结构的学习与信息整合结构的学习没有显著差异.(2)反应策略受到规则复杂性的影响,当类别结构中隐含的规则比较简单时,学习者使用规则策略;当类别结构中隐含的规则比较复杂时,学习者难以掌握规则,就会使用相似性策略.研究结果支持"难度观",而不支持多重系统理论.     

Rates of Non-Suicidal Self-Injury: A Cross-Sectional Analysis of Exposure

Research on the social influences associated with rates of non-suicidal self-injury (NSSI) is scarce and limited to studies of contagion within inpatient and residential treatment settings. Using an archival dataset that included 1,965 college students, the current study examined whether exposure to acts of NSSI and/or suicidal behavior in others was associated with increased rates of NSSI. Results supported hypotheses in that participants who knew someone who had engaged in NSSI only, or knew someone who engaged in both NSSI and suicidal behavior were more likely to have engaged in NSSI compared to those not exposed. The findings provide preliminary, albeit indirect, evidence of the potential for social modeling to influence rates of NSSI within college students. Directions for future studies are offered.     

Appetitive memory reconsolidation depends upon NMDA receptor-mediated neurotransmission

Memory persistence is a dynamic process involving the reconsolidation of memories after their reactivation. Reconsolidation impairments have been demonstrated for many types of memories in rats, and signaling at N-methyl-d-aspartate (NMDA) receptors appears often to be a critical pharmacological mechanism. Here we investigated the reconsolidation of appetitive pavlovian memories reinforced by natural rewards. In male Lister Hooded rats, systemic administration of the NMDA receptor antagonist (+)-5-methyl-10,11-dihydro-SH-dibenzo{a,d}cyclohepten-5,10-imine maleate (MK-801, 0.1 mg/kg i.p.) either before or immediately following a brief memory reactivation session abolished the subsequent acquisition of a new instrumental response with sucrose conditioned reinforcement. However, only when injected prior to memory reactivation was MK-801 effective in disrupting the maintenance of a previously-acquired instrumental response with conditioned reinforcement. These results demonstrate that NMDA receptor-mediated signaling is required for appetitive pavlovian memory reconsolidation.     

Gene Concepts and Genethics: Beyond Exceptionalism

The discursive explosion that was provoked by the new genetics could support the impression that the ethical and social problems posed by the new genetics are somehow exceptional in their very nature. According to this view we are faced with special ethical and social problems that create a challenge so fundamental that the special label of genethics is needless to justify. The historical account regarding the evolution of the gene concepts could serve us to highlight the limits of what we know about genes and what we can do with genes. The widespread notion about the exceptionality of genetic knowledge and its applicative possibilities is hardly justifiable and leads to misunderstandings regarding the conceptualization of the ethical and social problems we might face. Following a more realistic interpretation of the role of genes in human life we might avoid a whole set of fictive dilemmas and counterproductive regulatory efforts in bioethics. Bioethical discourse should move from the gene-centered scientific discourse toward the more sophisticated and complex discourses where human development represented as a matter of complex interactions between genomes and environments, between genes, educational factors, nutritional regimes, and other different developmental resources. If a gene is seen as one among the different developmental resources that are shaping a given human trait then both genethics and genetic exceptionalism could hardly be represented as a justified approach in discussing the ethical and social problems of genetics.     

Comments on ‘On “Bettering Humanity” in Science and Engineering Education’

The object of this communication is to reflect on the recent article by James Stieb in relation to an earlier article by Selvan.     

Social presence in online discussion groups: testing three conceptions and their relations to perceived learning

The correlation between three conceptions of social presence (seen as 1. a subjective quality of a medium that determines the quality of the communication and perception of others, 2. self-projection onto the group, and 3. identification with the group) and different aspects of perceived learning in online discussion groups were tested. Six hundreds and fifty nine students completed a web-based questionnaire that was distributed via 50 course Websites. Self projection, perception of others and identification with the group correlated positively with each other. They also correlated positively with most aspects of perceived learning. The subjective quality of the medium did not correlate with these conceptions and also did not correlate with any aspects of perceived learning. Thus, social presence may afford learning by setting a convenient climate. Alternatively, it may contribute only to the socioemotional source of perceived learning while leaving cognitive source unaffected.

Dissociations among ABA, ABC, and AAB recovery effects

In a human predictive learning experiment, the strengths of ABA, ABC, and AAB recovery effects after discrimination reversal learning were compared. Initially, a discrimination between two stimuli (X+, Y−) was trained in Context A. During Phase 2, participants received discrimination reversal training (X−, Y+) either in Context A (Group AAB) or in Context B (Group ABA, Group ABC). Testing occurred in the reversal context and in a neutral context (Group AAB, Group ABC) or in the reversal context and in the acquisition context (Group ABA). Recovery effects were similar in ABA and ABC procedures, whereas no AAB recovery effect occurred. Furthermore, the rate of discrimination reversal learning during Phase 2 was unaffected by whether training was conducted in the same or in a different context as initial learning. Results indicate that contextual stimuli are processed before interfering information is presented. These representations, however, do not acquire the ability to control performance.