Incremental Contribution in Step-Level Public Goods Games with Asymmetric Players

We consider public good games with asymmetric players in which players are assigned different endowments and must then decide privately how much to contribute to the group′s benefit. Each member receives a fixed reward-regardless of the magnitude of his/her contribution-if the sum of contributions is equal to or larger than an exogenously determined provision threshold and zero otherwise. The results show that (1) heterogeneous groups are less successful in providing public goods than homogeneous groups; (2) group members contribute the same proportion of their endowment regardless of its magnitude; (3) the distribution of endowments and the provision threshold interact; and (4) some subjects adhere to an equity principle, others maximize expected utility, and yet others do not subscribe to either of these two models.     

When the rich contribute more in public good dilemmas: the role of provision point level

The present research examined the effects of endowment size, provision point level and the opportunity to voice one's opinion on contributions in asymmetric public good dilemmas. Results from a first experiment showed that group members endowed with more resources contributed more when the required threshold for obtaining a public good was high rather than low. ‘Rich’ participants who reported that their personal contribution was more critical for success contributed more. However, most groups failed to surpass the high provision point threshold level. Results from a second experiment reveal that ‘rich’ participants given voice, contributed more than ‘rich’ participants not given a voice. Voice contributed to greater feelings of inclusiveness, higher contributions and increased the likelihood that the group surpassed the high provision point level. Copyright © 2006 John Wiley & Sons, Ltd.     

A Probabilistic Model of Criticality in a Sequential Public Good Dilemma

A public good (PG) is a commodity or service made available to all members of a group: its provision depends on the voluntary contribution of its members. Once provided, all members can enjoy the benefits of the PG, regardless of whether they contributed or not; hence, there is a temptation to “free-ride” in the hope that others will contribute. Rapoport (1987) showed that an important factor that affects cooperation (contribution) in a PG dilemma is the extent to which a group member is critical in providing it. Erev and Rapoport (1990) tested a game-theoretic model that yields deterministic predictions about the effects of criticality on cooperation in public good dilemmas. Based on research by Chen, Au, and Komorita (1996), we propose a probabilistic model of criticality. The model is tested and found to fit empirical data. Extensions of the model to situations with uncertain group size or provision point are discussed.     

When and how communicated guilt affects contributions in public good dilemmas

Two laboratory studies investigated how groups may deal with the strong emotions that social dilemmas often elicit. A first study showed that a new group member evaluated guilt communicated by a fellow group member as more instrumental than neutral emotion feedback when the amount of required resources to obtain the public good (i.e., provision point) was perceived as difficult to obtain. A second study revealed that participants use communicated guilt to draw inferences about both past and future contributions from all fellow group members. Participants also contributed more themselves and adhered to equality more often when guilt versus no emotion was communicated, but only when the provision point was high. Expected contributions from fellow group members mediated this effect.     

Self-control of feedback during motor learning: accounting for the absolute amount of feedback using a yoked group with self-control over feedback

A traditional control group yoked to a group that self-controls their reception of feedback receives feedback in the same relative and absolute manner. This traditional control group typically does not learn the task as well as the self-control group. Although the groups are matched for the amount of feedback they receive, the information is provided on trials in which the individual may not request feedback if he or she were provided the opportunity. Similarly, individuals may not receive feedback on trials for which it would be a beneficial learning experience. Subsequently, the mismatch between the provision of feedback and the potential learning opportunity leads to a decrement in retention. The present study was designed to examine motor learning for a yoked group with the same absolute amount of feedback, but who could self-control when they received feedback. Increased mental processing of error detection and correction was expected for the participants in the yoked self-control group because of their choice to employ a limited resource in the form of a decreasing amount of feedback opportunities. Participants in the yoked with self-control group committed fewer errors than the self-control group in retention and the traditional yoked group in both the retention and time transfer blocks. The results suggest that the yoked with self-control group was able to produce efficient learning effects and can be a viable control group for further motor learning studies.     

Which type of leader do I support in step‐level public good dilemmas? The roles of level of threshold and trust

The present research examined the moderating effect of the level of threshold on people's preferences for different leader types in step-level public good dilemmas. It was assumed that the primary focus of people in step-level public good dilemmas is to make sure that the group surpasses the threshold. Consequently, when the level of threshold is difficult to reach people are expected to provide more support for and cooperate with a leader that monitors and controls the contributions made toward the public good. However, if the threshold is easy to surpass people will focus more on whether the obtained public good or bonus will be distributed according to agreements, suggesting that people will provide more support to and cooperate with a leader that monitors and controls the distribution of the bonus. These predictions were confirmed across two experiments using a step-level public good paradigm with a dichotomous (Study 1) and a continuous (Study 2) contribution choice. Moreover, the results also revealed that perceptions of trust accounted, in part, for the effect of level of threshold on people's leadership preferences.     

The role of sparsely distributed representations in familiarity recognition of verbal and olfactory materials

We present the generalized signal detection theory (GSDT), where familiarity is described by a sparse binomial distribution of binary node activity rather than by normal distribution of familiarity. Items are presented in a distributed representation, where each node receives either noise only, or signal and noise. An old response (i.e., a “yes” response) is made if at least one node receives signal plus noise that is larger than the activation threshold, and item variability is determined by the distribution of activated nodes as the threshold is varied. A distinct representation leads to better performance and a lower ratio of new to old item variability, than a more distributed and less distinct representations. Here we apply the GSDT to empirical data on verbal and olfactory memory and suggest that verbal memory relies on a distinct neural item representation, whereas olfactory memory has a fuzzy neural representation leading to poorer memory and inducing a larger ratio of new to old item variability.     

Comparisons of Australians and Japanese on group-based cooperation

A cross-societal experiment with 49 Australian and 56 Japanese participants examined if the group heuristic account of ingroup-favoring behavior in a Prisoner's Dilemma game can be extended beyond the minimal group situation to a situation involving an enduring social category (i.e. participant's nationality). Participants played a Prisoner's Dilemma game five times, each time with a different partner. Two of the five partners were ingroup members, two were outgroup members, and the nationality of one partner was not known. Furthermore, one of the two ingroup (or outgroup) partners knew that the participant was a member of the same (or the other) nationality, and the other did not know it. The results indicated that the knowledge that the partner had about the nationality of the participant exerted an effect only when the partner was an ingroup member. No major difference was found between Australian and Japanese participants. An outgroup-favoring cooperation pattern was observed, but that pattern was shown to be a result of fairness concerns among Australian participants and of positive stereotypes of Australians among Japanese participants.     

Social Dilemmas

In social dilemma situations, each individual always receives a higher payoff for defecting than for cooperating, but all are better off if all cooperate than if all defect. Often, however, people in social dilemmas attend more to the group's payoffs than to their own, either automatically or to behave “appropriately.” But whereas social identity elicits cooperative behaviour in dilemmas, it is generally only for the benefit of an “in‐group.” Dilemmas between groups (requiring self‐sacrificial behaviour within) are often the most extreme. Consequently, the framing and manipulation of group identity is critical to cooperation rate as demonstrated by careful laboratory experimentation.     

A high-sensitivity drinkometer circuit with 60-Hz filtering

This article describes a drinkometer circuit designed to (1) detect licks even if the resistance of the skin on the animal’s feet becomes quite high due to low humidity, (2) automatically adjust its triggering threshold and increase its gain so that it will continue to detect licks when the water delivery spout is partially shorted to ground by high ambient humidity, (3) reject 60-Hz signals so they will not be treated as rapid licks by the data-recording system, and (4) tolerate the high voltages that can occur if the subject receives an electric shock while drinking. This lickometer will be especially useful in situations where it is not practical to monitor for possible signal failure due to high or low humidity, or where 60-Hz artifacts may contaminate the signal provided to a recording computer.     

The nature of co-authorship: a note on recognition sharing and scientific argumentation

Co-authorship of papers is very common in most areas of science, and it has increased as the complexity of research has strengthened the need for scientific collaboration. But the fact that papers have more than an author tends to complicate the attribution of merit to individual scientists. I argue that collaboration does not necessarily entail co-authorship, but that in many cases the latter is an option that individual authors might not choose, at least in principle: each author might publish in a separate way her own contribution to the collaborative project in which she has taken part, or papers could explicitly state what the contribution of each individual author has been. I ask, hence, why it is that scientists prefer to ‘pool’ their contributions instead of keeping them separate, if what they pursue in their professional careers (besides epistemic goals) is individual recognition. My answer is based on the view of the scientific paper as a piece of argumentation, following an inferentialist approach to scientific knowledge. A few empirical predictions from the model presented here are suggested in the conclusions.     

One team must win,the other need only not lose: an experimental study of an asymmetric participation game

We studied asymmetric competition between two (three‐person) groups. Each group member received an initial endowment and had to decide whether or not to contribute it. The group with more contributions won the competition and each of its members received a reward. The members of the losing group received nothing. The asymmetry was created by randomly and publicly selecting one group beforehand to be the winning group in the case of a tie. A theoretical analysis of this asymmetric game generates two qualitatively different solutions, one in which members of the group that wins in the case of a tie are somewhat more likely to contribute than members of the group that loses, and another in which members of the group that loses in the case of a tie are much more likely to contribute than members of the group that wins. The experimental results are clearly in line with the first solution. Copyright © 2005 John Wiley & Sons, Ltd.     

Stimulus and response contributions to the children's reaction-time repetition effect

Adults and 8-, 10-, 12-, and 14-year olds completed a serial reaction-time task with two stimuli mapped to each of two responses and 100-, 500-, and 1000-msec response-stimulus intervals (RSIs). Trials were classified as (1) identical (same stimulus and same response on two consecutive trials), (2) response equivalent (different stimulus but same response on two consecutive trials), or (3) different (different stimulus and different response on two consecutive trials). Identical and different trials were compared as a general indication of repetition effects. Response-equivalent minus identical reaction time identified stimulus contributions, and different minus response-equivalent reaction time identified response contributions. Adults received a repetition advantage at all RSIs and children received a repetition advantage at 500- and 1000- but not 100-msec RSIs. Stimulus contributions accounted for the repetition effect for both adults and children. At the 500- and 1000-msec RSIs, both the overall repetition effect and stimulus contribution were positive and decreased in magnitude as age increased. The response contribution was independent of RSI and was negative for 8- and 10-year-olds and near zero or positive for older performers. At the longer RSIs, positive stimulus contributions were sufficient to overcome the negative response contributions present for younger children.     

自由讨论条件下群体决策质量的影响因素

通过实验室实验考察了自由讨论条件下群体决策质量的影响因素,并对Stasser所提出的信息取样模型进行了验证,结果发现：(1)部分证实Stasser的信息取样模型。在信息不分享的条件下,如果讨论前群体成员的偏好比较一致时,群体的确倾向于讨论分享信息和群体所偏好的候选人的信息;但如果讨论前的偏好不一致或任务难度较低时,这一结论难以成立。(2)自由讨论条件下,群体规模的增加会增加分享信息的讨论量,而对非分享信息的讨论程度则无显著影响。而在任务难度方面,只有任务难度较大的情况下才有分享信息的讨论优势。     

Toward a theory of visual consciousness.

The visual brain consists of several parallel, functionally specialized processing systems, each having several stages (nodes) which terminate their tasks at different times; consequently, simultaneously presented attributes are perceived at the same time if processed at the same node and at different times if processed by different nodes. Clinical evidence shows that these processing systems can act fairly autonomously. Damage restricted to one system compromises specifically the perception of the attribute that that system is specialized for; damage to a given node of a processing system that leaves earlier nodes intact results in a degraded perceptual capacity for the relevant attribute, which is directly related to the physiological capacities of the cells left intact by the damage. By contrast, a system that is spared when all others are damaged can function more or less normally. Moreover, internally created visual percepts-illusions, afterimages, imagery, and hallucinations-activate specifically the nodes specialized for the attribute perceived. Finally, anatomical evidence shows that there is no final integrator station in the brain, one which receives input from all visual areas; instead, each node has multiple outputs and no node is recipient only. Taken together, the above evidence leads us to propose that each node of a processing-perceptual system creates its own microconsciousness. We propose that, if any binding occurs to give us our integrated image of the visual world, it must be a binding between microconsciousnesses generated at different nodes. Since any two microconsciousnesses generated at any two nodes can be bound together, perceptual integration is not hierarchical, but parallel and postconscious. By contrast, the neural machinery conferring properties on those cells whose activity has a conscious correlate is hierarchical, and we refer to it as generative binding, to distinguish it from the binding that might occur between the microconsciousnesses.     

Resource dilemmas with environmental uncertainty and asymmetric players

Groups of subjects participated in a series of 30 noncooperative independent single-trial resource dilemmas. On each trial the subjects in each group requested privately a number of points from a common pool. Individual requests were granted if and only if the total group request was equal to or smaller than the pool size. The pool size on each trial was sampled randomly from a uniform distribution that was common knowledge. Asymmetry in payoff was induced by assigning to each group member a different points-to-money exchange rate. The results show that as the uncertainty about the pool size increases subjects (1) overestimate the pool size, (2) increase their requests, and (3) expect others to increase their requests. In addition (4) individual requests and expectations regarding others' requests are inversely related to the exchange rates, reflecting attempts to equate payoffs across group members.     

Increasing participation and improving the quality of discussions in seventh-grade social studies classes

An experiment was conducted to evaluate procedures to improve classroom discussions in seventh-grade social studies classes. An increased number of students participated in discussions when rules were stated for discussions, students were praised for their contributions, the teacher restated or paraphrased students' contributions aloud or on the blackboard, the teacher planned an outline of discussion questions, student contributions to discussions were recorded and were used to determine part of the students' grades for the class, and discussion grades were publicly posted.The second part of the study focused on procedures designed to improve quality of classroom discussions. Students were taught to participate in discussions by providing reasons for their statements, comparisons between different points, or examples supporting their statements. As each type of contribution was taught, recorded, and counted toward part of the students' classroom grades, each type of contribution increased. Ratings of discussions by outside judges consisting of junior high school teachers, junior high school students, and persons experienced in conducting discussions, indicated that the training increased the overall quality of the discussions. Use of the quality training procedures, however, resulted in decreased levels of overall participation in discussion, a decrease that was reversed by the use of a group contingency for participation. Finally, the discussions after training seemed to be preferred by both the teacher and the students.     

Reciprocity in groups: information‐seeking in a public goods game

Questions remain about the details of the reciprocal strategies people use in the context of group cooperation. Here we report an experiment in which participants in public goods games could access information about the lowest, median, or highest contribution to the public good before making their own contribution decisions. Results suggest that people have clear preferences for particular pieces of information and that information preferences vary systematically across individuals as a function of their contribution strategies. Specifically, participants playing reciprocal strategies sought information about the median contribution, free riders preferred to view the highest contribution, and altruists had inconsistent preferences. By including a treatment in which people could pay to see information rather than obtaining it for free, we found that people were willing to incur costs to acquire information, particularly those using a reciprocal strategy. Further, adding a cost to view information decreased aggregate contributions, possibly because the motivation to induce others' reciprocal contributions diminished under these conditions. Copyright © 2007 John Wiley & Sons, Ltd.     

When emotions of others affect decisions in public good dilemmas: An instrumental view

The present research examines whether the emotional display (i.e. anger vs. guilt) of another group member affects people's decision‐making in a public good dilemma. In two experiments we investigated whether the expressed emotion is particularly informative when communicated by a group member who is highly instrumental in reaching the provision point. A first experiment demonstrated that participants were more likely to exit the group when anger as opposed to guilt was communicated, but especially when the group member displaying the emotion was able to contribute many endowments to the public good. Expected justice (based on past inferences) in the group mediated this effect, suggesting that communicated anger signals more than guilt that the group will not set out to achieve fairness. In agreement with this, a second experiment showed that when it was not possible to exit the group, participants preferred to install a democratic leader more when a wealthy group member communicated anger as opposed to guilt. Additionally, this study provided experimental evidence that a communicated emotion is only used for subsequent decision‐making when more explicit information (i.e. a promise to contribute) is absent. Copyright © 2008 John Wiley & Sons, Ltd.     

Ally or adversary: The effect of identifiability in inter-group conflict situations

People’s tendency to be more generous towards identifiable victims than towards unidentifiable or statistical victims is known as the identifiable victim effect. Recent research (Kogut & Ritov, 2007) called the generality of the effect into question, showing that in cross-national contexts, identifiability affects mostly willingness to help victims belonging to one’s ‘in-group’. The present research extends the investigation by examining the identifiability effect in inter-group conflict situations. In three experiments, employing hypothetical contributions as well as real monetary allocation in a dictator-game, we found that identifiability increased generosity towards a member of the adversary group, but it decreased generosity towards a member of one’s own group. Possible mechanisms underlying this interaction are discussed.