Three Models of Sequential Belief Updating on Uncertain Evidence

Jeffrey updating is a natural extension of Bayesian updating to cases where the evidence is uncertain. But, the resulting degrees of belief appear to be sensitive to the order in which the uncertain evidence is acquired, a rather un-Bayesian looking effect. This order dependence results from the way in which basic Jeffrey updating is usually extended to sequences of updates. The usual extension seems very natural, but there are other plausible ways to extend Bayesian updating that maintain order-independence. I will explore three models of sequential updating, the usual extension and two alternatives. I will show that the alternative updating schemes derive from extensions of the usual rigidity requirement, which is at the heart of Jeffrey updating. Finally, I will establish necessary and sufficient conditions for order-independent updating, and show that extended rigidity is closely related to these conditions.     

Improving sixth-grade students perceptions of high-effort assignments by assigning more work: Interaction of additive interspersal and assignment effort on assignment choice

Sixth-grade students were exposed to two pairs of mathematics assignments. Assignment Pair A included a high-effort and a moderate-effort assignment, each containing 18 three-digit by two-digit (3×2) problems. Assignment Pair B was similar except the high-effort assignment contained six additional one-digit by one-digit (1×1) problems interspersed following every third 3×2 problem. After exposure to each pair of assignments, students ranked assignments and chose a new assignment for homework. Analysis of Assignment Pair A data showed students preferred the moderate-effort assignment. Analysis of interactions showed that interspersing the additional brief problems to the high-effort assignment caused significantly more students to choose the high-effort assignment for homework and rank it as requiring less effort and time to complete and as being less difficult than the moderate-effort assignment. Results support the hypothesis that a discrete task is a reinforcer and suggest that educators can increase the probability of students engaging in more challenging assignments that require more effort to complete by interspersing additional brief tasks. Applied and theoretical implications are discussed along with future research.     

Heroic DVD portrayals: What US and Taiwanese adolescents admire and understand

Viewing media aggression can be a risk factor for the long-term well being of viewers, and heroes have been targeted as a major risk factor in this relationship because they commit justified acts of aggression. However, little is known about the specific aspects of heroic conduct that viewers find worthy of emulation. We examined US and Taiwanese adolescents' and college students' identification with, and perceptions of, heroic characters portrayed in a DVD narrative as well as their comprehension of the narrative. Those who thought that certain characters were heroes were more likely to identify with them. However, the qualities that viewers found attractive in heroes were compassion and thinking before using force, not aggression or vengeance. Those who did not understand the program well were more likely to identify with the villain, and they were also more likely to misattribute prosocial qualities to the villain. The results suggest that at least for older viewers, heroic behavior is admired and emulated for prosocial rather than antisocial conduct, and that poor plot-comprehension is one factor that contributes to younger viewers' identification with, and imitation of, antisocial role models.     

分部评分模型与其它几种多级模型的比较

项目反应理论(IRT)是当前教育与心理测量领域的一个重大进展,也日益成为当今测验领域的一个热点。本文对IRT理论中的二个重要评分模型PCM与GPCM作了简要的介绍。并较详细地对PCM与GPCM模型的逻辑结构及其适用范围进行了论述,指出了它们与其它几种重要模型之间的关系及不同之处。     

行政伦理困境与行政行为选择

行政责任的特点之一是其道德性 ,在行政行为选择中伦理动因占据着核心位置。行政伦理困境是行政行为选择中经常遇到的一种特殊情境 ,行政伦理困境与行政行为选择经常相伴而生 ,因此 ,谈及行政伦理困境必然涉及到行政行为选择。     

An Empirical Analysis of Interspersal Research: Evidence, Implications, and Applications of the Discrete Task Completion Hypothesis

Because assignment completion is often reinforced, researchers have posited that when students work on assignments with many discrete tasks (e.g., 20 mathematics problems), that each completed discrete task may be a conditioned reinforcer (e.g., Skinner et al., 1999). If the discrete task completion hypothesis is accurate, then relative task completion rates should influence choice behavior in the same manner as relative rates of reinforcement. In the current study, previous interspersal research was combined across experiments and regression analysis revealed a linear relationship between relative problem completion rates (RPCR) and choice in accordance with the matching law (Herrnstein, 1961, 1970). These results support the discrete task completion hypothesis and suggest that interspersing additional brief tasks enhances interval schedules of reinforcement. Theoretical and applied implications of the current study and the discrete problem completion hypothesis are discussed and directions for future research are provided.     

A Spanish translation of Mehrabian and Russell's emotionality scales for environmental consumer psychology

The development of a translation of Mehrabian and Russell's scales for the measurement of pleasure, arousal and dominance from the original English to a Spanish version for use in Venezuela is described. The translated scales were administered to two samples of middle‐class Venezuelan consumers (n = 127,n = 127) between the ages of 20 and 50, among whom males and females were represented approximately equally. Internal reliability (measured by Cronbach's alpha) and scale validity (measured by factor analysis) indicate that the translated scales are suitable for consumer and other social psychological research in Spanish. Copyright © 2002 Henry Stewart Publications Ltd.     

The influence of competitive status (winner/loser) on the behavior of male rats in three models of anxiety

Studies indicate that features such as prior stressful experience, strain, gender, and age can influence the behavior of rats in animal models of anxiety. In the present study, we examined the possible influence of competitive status (winner/loser) in three such models: the elevated plus‐maze, the open field, and the social interaction test. One hundred to 135‐day‐old male Wistar rats were conditioned to traverse a straight runway tube to obtain food. Subsequently, two rats were placed at the same time in the runway tube and, being unable to pass each other, one of them pushed the other to the opposite end‐box. The rats were categorized as winners or losers in this competition. One week after the straight runway tube test, the rats were submitted to the anxiety models, where it was observed that winner rats showed greater locomotor activity than the losers in the three models studied. Furthermore, winner rats showed less immobility and higher central and total locomotor activity in the open field and a greater duration of social interaction in the social interaction test. These results suggest that competitive status has an influence on the locomotor activity of rats in animal models of anxiety. However, whether competitive status influences anxiety as assessed in these models is unclear, and further investigations are warranted. Aggr. Behav. 28:164–171, 2002. © 2002 Wiley‐Liss, Inc.     

A re‐examination of probability matching and rational choice

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.     

Effects of initial choices in the prisoner's dilemma

In the two‐person prisoner's dilemma game (PDG), there is considerable evidence that the tit‐for‐tat (TFT) strategy is most effective in inducing the other person to cooperate. One of the important features of the TFT strategy is that it cooperates on the first trial. We varied the initial choices of a simulated other, and tested the effects of (a) initial choices (cooperation or defection), and (b) persistence of initial choices: unilateral cooperation (or defection) on the first trial, first two trials, or first four trials. Results showed that a cooperative strategy—one that starts with cooperative choices—induced greater cooperation than a strategy that started with defections. The results of this study clearly show that (a) a cooperative strategy—one that initiates unilateral cooperation at the outset and then adopts a TFT strategy—is very effective in inducing subsequent cooperation from the other party, (b) the effectiveness of a cooperative strategy varies directly with the cooperative orientation of the other party (a cooperative strategy is more effective against a cooperative than a competitive person), and (c) initial cooperation is more effective if it is repeated more than once. Copyright © 2002 John Wiley & Sons, Ltd.