In a typical probability learning task participants are presented with a repeated choice between two response alternatives, one of which has a higher payoff probability than the other. Rational choice theory requires that participants should eventually allocate all their responses to the high-payoff alternative, but previous research has found that people fail to maximize their payoffs. Instead, it is commonly observed that people match their response probabilities to the payoff probabilities. We report three experiments on this choice anomaly using a simple probability learning task in which participants were provided with (i) large financial incentives, (ii) meaningful and regular feedback, and (iii) extensive training. In each experiment large proportions of participants adopted the optimal response strategy and all three of the factors mentioned above contributed to this. The results are supportive of rational choice theory. Copyright # 2002 John Wiley & Sons, Ltd.key words probability matching; maximization; choice; rationality; feedback; payoffs; learning; reinforcement A striking violation of rational choice theory is commonly observed in simple repeated binary choice tasks in which a payoff is available with higher probability given one response than another. In such tasks people often tend to 'match' probabilities: That is, they allocate their responses to the two options in proportion to their relative payoff probabilities. Thus suppose that a monetary payoff of fixed size is given with probability p ¼ 0.7 for choosing left and with probability 1 À p ¼ 0.3 for choosing right. Probability matching refers to behavior in which left is chosen on about 70% of trials and right on 30%. Such responding violates rational choice theory because the optimal strategy in such tasks, after an initial period of experimentation and assuming that the payoff probabilities are stationary, is always to select the option associated with the higher probability of payoff. On any trial, the expected payoff for choosing left is higher than the expected payoff for choosing right.

Theoretical models suggest that gratitude is linked to increased prosociality. To date, however, there is a lack of a comprehensive quantitative synthesis of results to support this claim. In this review we aimed to (a) examine the overall strength of the association between gratitude and prosociality, and (b) identify the theoretical and methodological variables that moderate this link. We identified 252 effect sizes from 91 studies across 65 papers-(Total N = 18,342 participants). The present meta-analysis revealed a statistically significant, and moderate positive correlation between gratitude and prosociality (r = .374). This association was significantly larger among studies that assessed outcomes relative to outcomes, and in particular among studies that examined -compared with-reciprocity. Studies that examined gratitude as an reported significantly larger effect size studies assessing gratitude as a. Studies that examined gratitude (in response to other's kindness) had a stronger effect that gratitude that focuses on the appreciation of what is valued and cherished in life. Finally, studies that manipulated gratitude in vivo (e.g., economic games) had larger effect sizes compared with those based on recalled incidents when the person felt grateful. We describe the theoretical and practical significance of the results. (PsycINFO Database Record

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Humans are characterized by an unusual level of prosociality. Despite this, considerable indirect evidence suggests that biological kinship plays an important role in altruistic behaviour. All previous reports of the influence of kin selection on human altruism have, however, used correlational (rather than experimental) designs, or imposed only a hypothetical or negligible time cost on participants. Since these research designs fail either to control for confounding variables or to meet the criteria required as a test of Hamilton's rule for kin selection (that the altruist pays a true cost), they fail to establish unequivocally whether kin selection plays a role. We show that individuals from two different cultures behave in accordance with Hamilton's rule by acting more altruistically (imposing a higher physical cost upon themselves) towards more closely related individuals. Three possible sources of confound were ruled out: generational effects, sexual attraction and reciprocity. Performance on the task however did not exhibit a perfect linear relationship with relatedness, which might reflect either the intrusion of other variables (e.g. cultural differences in the way kinship is costed) or that our behavioural measure is insufficiently sensitive to fine‐tuned differences in the way individuals view their social world. These findings provide the first unequivocal experimental evidence that kinship plays a role in moderating altruistic behaviour. Kinship thus represents a baseline against which individuals pitch other criteria (including reciprocity, prosociality, obligation and a moral sense) when deciding how to behave towards others.

Foreign language (FL) films with subtitles are becoming increasingly popular, and many European countries use subtitling as a cheaper alternative to dubbing. However, the extent to which people process subtitles under different subtitling conditions remains unclear. In this study, participants watched part of a film under standard (FL soundtrack and native language subtitles), reversed (native language soundtrack and FL subtitles), or intralingual (FL soundtrack and FL subtitles) subtitling conditions while their eye movements were recorded. The results revealed that participants read the subtitles irrespective of the subtitling condition. However, participants exhibited more regular reading of the subtitles when the film soundtrack was in an unknown FL. To investigate the incidental acquisition of FL vocabulary, participants also completed an unexpected auditory vocabulary test. Because the results showed no vocabulary acquisition, the need for more sensitive measures of vocabulary acquisition are discussed. Finally, the reading of the subtitles is discussed in relation to the saliency of subtitles and automatic reading behavior.

Participants can transfer grammatical knowledge acquired implicitly in 1 vocabulary to new sequences instantiated in both the same and a novel vocabulary. Two principal theories have been advanced to account for these effects. One suggests that sequential dependencies form the basis for cross-domain transfer (e.g., Z. Dienes, G. T. M. Altmann, & S. J. Gao, 1999). Another argues that a form of episodic memory known as abstract analogy is sufficient (e.g., L. R. Brooks & J. R. Vokey, 1991). Three experiments reveal the contributions of the 2. In Experiment 1 sequential dependencies form the only basis for transfer. Experiment 2 demonstrates that this process is impaired by a change in the distributional properties of the language. Experiment 3 demonstrates that abstract analogy of repetition structure is relatively immune to such a change. These findings inform theories of artificial grammar learning and the transfer of grammatical knowledge.

In everyday life, many of the decisions that we make are made on behalf of other people. A growing body of research suggests that we often, but not always, make different decisions on behalf of other people than the other person would choose. This is problematic in the practical case of legally designated surrogate decision makers, who may not meet the substituted judgment standard. Here, we review evidence from studies of surrogate decision making and examine the extent to which surrogate decision making accurately predicts the recipient’s wishes, or if it is an incomplete or distorted application of the surrogate’s own decision-making processes. We find no existing domain-general model of surrogate decision making. We propose a framework by which surrogate decision making can be assessed and a novel domain-general theory as a unifying explanatory concept for surrogate decisions.

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