Coalition bargaining in four games that include a veto player.

Tested the predictions of 3 models of coalition behavior. 120 graduate students played each of 4 games, rotating among the 5 player positions (including a veto player) between games. The games were played under 1 of 3 time pressure/default conditions: (a) no time pressure, (b) a condition such that the constant payoff to coalitions was lost if an agreement was not reached in 3 attempts, and (c) a condition such that the payoff for no agreement was fixed at 60 points for the veto player and 10 for the other players. The veto players' payoffs varied over games and tended to increase as play continued, at times approaching the entire payoff. Thus, the weighted probability (S. S. Komorita, 1974) and Roth-Shapley (A. E. Roth, 1977; L. S. Shapley, 1953) models were not supported; the core model received some support. The default conditions had little effect. The likelihood of socially beneficial behavior in competitively motivating situations is discussed. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predicting behavior in economic games by looking through the eyes of the players.

Social scientists often rely on economic experiments such as ultimatum and dictator games to understand human cooperation. Systematic deviations from economic predictions have inspired broader conceptions of self-interest that incorporate concerns for fairness. Yet no framework can describe all of the major results. We take a different approach by asking players directly about their self-interest—defined as what they want to do (pleasure-maximizing options). We also ask players directly about their sense of fairness—defined as what they think they ought to do (fairness-maximizing options). Player-defined measures of self-interest and fairness predict (a) the majority of ultimatum-game and dictator-game offers, (b) ultimatum-game rejections, (c) exiting behavior (i.e., escaping social expectations to cooperate) in the dictator game, and (d) who cooperates more after a positive mood induction. Adopting the players' perspectives of self-interest and fairness permits better predictions about who cooperates, why they cooperate, and when they punish noncooperators. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A test of four theories of coalition formation: Effects of payoffs and resources.

Used 3 coalition games to test the minimum resource, minimum power, and bargaining theories against each other and against equal excess theory; 144 male undergraduates were Ss. In Game X, all winning coalitions had the same payoffs but players had different resources; in Game Y, winning coalitions had different payoffs and players had different resources. The characteristic functions of the games (payoffs for the coalitions) were the same for Games Y and Z, and the resource distributions were the same for Games X and Z. Coalition behavior was virtually the same in Games Y and Z, but coalition behavior in these games differed from that in Game X. Thus, when there were differences in both coalition payoffs and individual resources, the payoffs rather than the resources tended to influence coalition behavior. Coalition behavior in Games Y and Z was best accounted for by equal excess theory, coalition behavior in Game X by bargaining theory. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of resources and alternatives on coalition formation.

Previous research has indicated that coalition formation is influenced by the players' resources and alternatives (game structure). However, on almost all occasions when both resources and game structure have been varied, they have been confounded. In the present study with 224 undergraduates, 4 different 4-person simple games were used, based on the same distribution of resources. These games were played both with and without resources being assigned. Thus, resource assignment and game structure were not confounded. Coalition frequencies and reward divisions were minimally influenced by assigned resources. Coalition frequency was inversely related to coalition size. Players' outcomes were inversely related to the size of the winning coalition and directly related to the number of their alternative small coalitions. Players' mean payoffs over all trials were related to the number and mean size of their minimal winning coalitions, relative to the other players. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in outcomes in coalition bargaining.

Examined the results of earlier coalition experiments that concluded that the coalition with the largest payoff per member occurs most frequently and the reward division is close to an equal split (except for frequent deviations from equal share payoffs). The present authors hypothesized that inconsistencies in previous research were due to differences in experimental procedure and to Ss' familiarity with coalition games. In the present study, 240 male undergraduates played a 4-person multivalued apex game for 6 trials. Three games and 2 procedures were used. The 2 procedures differed in the number of rounds of offers and counteroffers required to form a coalition. As hypothesized, results indicate that deviations from equal shares increased over trials of the game and were greater with the procedure that required more rounds of bargaining. Findings regarding payoff divisions are in the direction predicted by the bargaining theory and equal excess model of coalition formation, but findings regarding frequencies of coalitions are contrary to the predictions of both theories. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Base-rate and payoff effects in multidimensional perceptual categorization

The optimality of multidimensional perceptual categorization performance with unequal base rates and payoffs was examined. In Experiment 1, observers learned simultaneously the category structures and base rates or payoffs. Observers showed conservative cutoff placement when payoffs were unequal and extreme cutoff placement when base rates were unequal. In Experiment 2, observers were trained on the category structures before the base-rate or payoff manipulation. Simultaneous base-rate and payoff manipulations tested the hypothesis that base-rate information and payoff information are combined independently. Observers showed (a) small suboptimalities in base-rate and payoff estimation, (b) no qualitative differences across base-rate and payoff conditions, and (c) support for the hypothesis that base-rate and payoff information is combined independently. Implications for current theories of base-rate and payoff learning are discussed.     

Young children's preoccupation with their own payoffs in strategic analysis of 2?×?2 games.

72 4–10 yr olds played 3 mixed-motive games, each game having one dominating strategy. Half of the Ss first chose their own strategy and then guessed what the other player (experimenter) chose; the other half proceeded in the reverse order. Ss at all ages showed a preoccupation with their own payoffs and a lack of interest in the other player's payoffs. Although the younger Ss centered on their maximum payoff, older Ss were able and willing to pay attention to the other player's interests, but only if doing so helped them to improve their own strategy. This developmental improvement seems due to the growing ability to coordinate 2 players' strategies. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trading goods versus sharing money: An experiment testing whether fairness and efficiency are frame dependent.

Systematic experiments with distribution games have shown that participants are strongly motivated by considerations of fairness and efficiency. This evidence, however, results mainly from experimental designs in which money is shared directly. Furthermore, fairness does not necessarily require equal payoffs, but may instead require equal allocations. We investigate experimentally the frame dependency of reaching equal (commodity or payoff) splits by systematically comparing net-trade proposals and payoff proposals for the same exchange economy with two traders, two commodities and multi-period negotiations. We can confirm the hypothesis that asking participants to allocate money directly, rather than more naturally via the allocation of commodities, is far from being harmless and likely overstates fairness and efficiency concerns. What is more, we try to apply the insights gained from our experiment to management problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Game theory and reciprocity in some extensive form experimental games

We examine decision making in two-person extensive form game trees using nine treatments that vary matching protocol, payoffs, and payoff information. Our objective is to establish replicable principles of cooperative versus noncooperative behavior that involve the use of signaling, reciprocity, and backward induction strategies, depending on the availability of dominated direct punishing strategies and the probability of repeated interaction with the same partner. Contrary to the predictions of game theory, we find substantial support for cooperation under complete information even in various single-play treatments.     

Test of the bargaining and equal excess theories of coalition formation: Effects of experience, information about payoffs, and monetary stakes.

Compared the bargaining and equal excess theories of coalition formation for their accuracy in predicting the effects of bargaining experience, information about coalition payoffs, and monetary stakes on coalition behavior in a 5-person game. 380 male undergraduates served as Ss. Manipulation of bargaining experience involved having each group play 4 trials of the game. Information about payoffs was varied by giving players in half the groups information about the payoffs for all the possible coalitions, and those in the other half of the groups information only about the payoffs for the coalitions of which they could be a member. Monetary stakes were manipulated by having Ss in half the groups play the game for the chance of winning $3, and Ss in the other half of the groups play the game for the chance of winning $50. Consistent with previous findings, monetary stakes had no effect on coalition behavior. Both bargaining experience and payoff information, however, had effects on coalition behavior, and these effects tended to support bargaining theory rather than equal excess theory. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multiagent reinforcement learning in the Iterated Prisoner's Dilemma

Reinforcement learning (RL) is based on the idea that the tendency to produce an action should be strengthened (reinforced) if it produces favorable results, and weakened if it produces unfavorable results. Q-learning is a recent RL algorithm that does not need a model of its environment and can be used on-line. Therefore, it is well suited for use in repeated games against an unknown opponent. Most RL research has been confined to single-agent settings or to multiagent settings where the agents have totally positively correlated payoffs (team problems) or totally negatively correlated payoffs (zero-sum games). This paper is an empirical study of reinforcement learning in the Iterated Prisoner's Dilemma (IPD), where the agents' payoffs are neither totally positively nor totally negatively correlated. RL is considerably more difficult in such a domain. This paper investigates the ability of a variety of Q-learning agents to play the IPD game against an unknown opponent. In some experiments, the opponent is the fixed strategy Tit-For-Tat, while in others it is another Q-learner. All the Q-learners learned to play optimally against Tit-For-Tat. Playing against another learner was more difficult because the adaptation of the other learner created a non-stationary environment, and because the other learner was not endowed with any a priori knowledge about the IPD game such as a policy designed to encourage cooperation. The learners that were studied varied along three dimensions: the length of history they received as context, the type of memory they employed (lookup tables based on restricted history windows or recurrent neural networks that can theoretically store features from arbitrarily deep in the past), and the exploration schedule they followed. Although all the learners faced difficulties when playing against other learners, agents with longer history windows, lookup table memories, and longer exploration schedules fared best in the IPD games.     

The norm of self-interest.

The self-interest motive is singularly powerful according to many of the most influential theories of human behavior and the layperson alike. In the present article the author examines the role the assumption of self-interest plays in its own confirmation. It is proposed that a norm exists in Western cultures that specifies self-interest both is and ought to be a powerful determinant of behavior. This norm influences people's actions and opinions as well as the accounts they give for their actions and opinions. In particular, it leads people to act and speak as though they care more about their material self-interest than they do. Consequences of misinterpreting the "fact" of self-interest are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotional intelligence in the National Hockey League.

The purpose of the present study was threefold: a) to evaluate the standing on emotional intelligence of National Hockey League players, relative to the general population, b) to evaluate the relationship of draft rank and emotional intelligence (EI) measures to hockey performance, and c) to evaluate the relative predictive value of these measures to performance indices: total NHL points and NHL games played. During the 2003-04 hockey season, 79 players across 24 NHL teams completed the Bar-On EQ-i. The findings indicated that years-since-draft was the strongest predictor of performance and draft rank was the weakest predictor of performance. With respect to EI, both intrapersonal competency and general mood added significant variance to predictions of number of NHL points and games played. Implications for predicting performance in the NHL, amongst draft prospects, is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Individual heuristics and the dynamics of cooperation in large groups": Additional results using analytical methods.

The authors elaborate on the simulation study "Individual Heuristics and Dynamics of Cooperation in Large Groups" by D. M. Messick and W. B. G. Liebrand (see record 1995-17369-001). Messick and Liebrand demonstrated that, in problematic social situations in large groups, stable levels of cooperation can be established even if actors are assumed to be guided by simple behavioral strategies. Among other things, they provided a theory underlying their simulation system. The present article elaborates on Messick and Liebrand's theory and provides a model that predicts the results of simulation runs for a set of simulation systems with more general properties. This enabled deduction of additional, sometimes counterintuitive results. For example, it is shown that it need not be the case that the equilibrium level of cooperation increases with an increasing payoff for mutual cooperation and that it is likely that the equilibrium level of cooperation increases with an increasing payoff for mutual defection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of prior experience on coalition bargaining.

Tested S. S. Komorita's (see record 1981-01237-001) equal excess model. 126 male undergraduates played 3-person multivalued games. All groups played 4 trials of a test game either for points that were later converted to prizes or for money. Prior to the test game, triads in different conditions were exposed to a varying number of coalition games. Results show a large and significant effect on coalition payoffs: The greater the experience, the greater the deviation of payoffs from equal splits. Thus, the results of many coalition experiments may be restricted to naive bargainers and may not be generalized to experienced, sophisticated bargainers. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Playing games.

In a recent Handbook of Research Methods in Child Development (see record 1961-06134-000), a subsection "Ethical Problems of Research" (p. 28) disposes of the problem of eliciting preschool children's cooperation in research projects with the following statement: "With preschool children the request to play some games with the experimenter is probably as good as can be done." The current author takes issue with this statement, and considers what happens when a psychologist approaches a preschool child with only this games cliché to guide him. Additionally, the current author examines what could be done to make game players more perceptive and game playing more productive. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential sensitivity to the wake-promoting actions of norepinephrine within the medial preoptic area and the substantia innominata.

Mapping studies were conducted to delineate the site(s) of action for the arousal-enhancing actions of norepinephrine (NE) within the basal forebrain region encompassing the medial preoptic area (MPOA) and the substantia innominata (SI). Varying doses of NE, the β-agonist, isoproterenol, or the α?-agonist, phenylephrine, were infused into the MPOA or SI in the resting rat. Infusions of NE (4 nmol, 16 nmol/150 nl), isoproterenol (15 nmol/150 nl), and phenylephrine (40 nmol/250 nl) into the MPOA elicited robust increases in waking. In contrast, neither isoproterenol or phenylephrine infusions into the SI altered behavioral state. NE infusions into the SI increased waking only at the highest dose, and at this dose there was an anatomical gradient for NE-induced waking, with infusions placed farther from the MPOA, producing smaller increases in waking. Thus, in contrast to the MPOA, the SI is relatively insensitive to the wake-promoting actions of NE. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distributive judgments under uncertainty: Paccioli's game revisited.

Many decision biases arise from the inability to ignore past events. The coherence of decisions is also compromised by the inability to fully use information related to the future. In Paccioli's game, a stake of money goes to the first player to score a certain number of wins. When the game is prematurely interrupted, they may divide the stake according to the proportions of wins relative to rounds played. Alternatively, they may assess the probability that a player would reach the criterion number of wins first if the game were continued. The first decision rule (ratio), which is past-oriented, leads to contradictions across games. The second rule (probability), which is future-oriented, does not. In seven studies, use of the ratio rule emerges across testing methods, in games of chance and games of skill, and independently of extraneous factors (such as random responding, lack of awareness, or proneness to other past-oriented biases). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Democracy under uncertainty: The wisdom of crowds and the free-rider problem in group decision making.

We introduce a game theory model of individual decisions to cooperate by contributing personal resources to group decisions versus by free riding on the contributions of other members. In contrast to most public-goods games that assume group returns are linear in individual contributions, the present model assumes decreasing marginal group production as a function of aggregate individual contributions. This diminishing marginal returns assumption is more realistic and generates starkly different predictions compared to the linear model. One important implication is that, under most conditions, there exist equilibria where some, but not all, members of a group contribute, even with completely self-interested motives. An agent-based simulation confirmed the individual and group advantages of the equilibria in which behavioral asymmetry emerges from a game structure that is a priori perfectly symmetric for all agents (all agents have the same payoff function and action space but take different actions in equilibria). A behavioral experiment demonstrated that cooperators and free riders coexist in a stable manner in groups performing with the nonlinear production function. A collateral result demonstrated that, compared to a dictatorial decision scheme guided by the best member in a group, the majority/plurality decision rules can pool information effectively and produce greater individual net welfare at equilibrium, even if free riding is not sanctioned. This is an original proof that cooperation in ad hoc decision-making groups can be understood in terms of self-interested motivations and that, despite the free-rider problem, majority/plurality decision rules can function robustly as simple, efficient social decision heuristics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)