Collective rationality in interactive decisions: evidence for team reasoning

Decision theory and game theory rest on a fundamental assumption that players seek to maximize their individual utilities, but in some interactive decisions it seems intuitively reasonable to aim to maximize the utility of the group of players as a whole. Such team reasoning requires collective preferences and a distinctive mode of reasoning from preferences to decisions. Findings from two experiments provide evidence for collective preferences and team reasoning. In lifelike vignettes (Experiment 1) and abstract games (Experiment 2) with certain structural properties, most players preferred team-reasoning strategies to strategies supporting unique Nash equilibria, although individually rational players should choose equilibrium strategies. These findings suggest that team reasoning predicts strategy choices more powerfully than orthodox game theory in some games.     

Subgames within Large Games and the Heuristic of Imitation

We study repeated normal form games where the number of players is large. We argue that it is interesting to look at such games as being divided into subgames, each of which we call a neighbourhood. The structure of such a game is given by a graph G whose nodes are players and edges denote visibility. The neighbourhoods are maximal cliques in G. The game proceeds in rounds where in each round the players of every clique X of G play a strategic form game among each other. A player at a node v strategises based on what she can observe, i.e., the strategies and the outcomes in the previous round of the players at vertices adjacent to v. Based on this, the player may switch strategies in the same neighbourhood, or migrate to another neighbourhood. We are interested in addressing questions regarding the eventual stability of such games. We incrementally impose constraints on the ‘types’ of the players. First, we look at players who are unconstrained in their strategising abilities, in that, players who may use unbounded memory. We then consider the case of memoryless players. We show that in both these cases the eventual stability of the game can be characterised in terms of potentials. We then introduce a simple modal logic in which the types of the players can be specified. We show that when the players play according to these specified types, it can be effectively decided whether the game stabilises. Finally, we look at the important heuristic of imitation. Simple imitative strategies can be specified in the logic introduced by us. We show that in a population of optimisers and imitators, we can decide how ‘worse-off’ the imitators are by playing imitative strategies rather than optimal ones.     

National security games

Issues that arise in using game theory to model national security problems are discussed, including positing nation-states as players, assuming that their decision makers act rationally and possess complete information, and modeling certain conflicts as two-person games. A generic two-person game called the Conflict Game, which captures strategic features of such variable-sum games as Chicken and Prisoners' Dilemma, is then analyzed. Unlike these classical games, however, the Conflict Game is a two-stage game in which each player can threaten to retaliate — and carry out this threat in the second stage — if its opponent chose noncooperation in the first stage.Conditions for the existence of different pure-strategy Nash equilibria, or stable outcomes, are found, and these results are extended to situations in which the players can select mixed strategies (i.e., make probabilistic threats or choices). Although the Conflict Game sheds light on the rational foundations underlying arms races, nuclear deterrence, and other strategic situations, more detailed assumptions are required to tie this generic game to specific conflicts.Steven J. Brams gratefully acknowledges the financial support of the National Science Foundation under Grant No. SES85-20154, the Sloan Foundation, and the Guggenheim Foundation.D. Marc Kilgour gratefully acknowledges the financial support of the Natural Sciences and Engineering Research Council of Canada under Grant No. A8974.     

Information and the complementarity game

Complementarity games are explorative games between two players. The deterministic rules of the game are known to both players. The first player freely chooses among a finite number of states of the game but tells nobody of this decision. The second player accesses the game only by primitive, symbolic input‐output interfaces. The task of the second player is to find out the unknown state by input‐output experiments. The logic resulting from this scenario resembles‐ quantum logic in many aspects. It is the empirical logic of choice for virtual realities.     

Ambiguous games: Evidence for strategic ambiguity aversion

The problem of ambiguity in games is discussed, and a class of ambiguous games is identified. A total of 195 participants played strategic-form games of various sizes with unidentified co-players. In each case, they first chose between a known-risk game involving a co-player indifferent between strategies and an equivalent ambiguous game involving one of several co-player types, each with a different dominant strategy, and then they chose a strategy for the preferred game. Half the players knew that the ambiguous co-player types were equally likely, and half did not. Half expected the outcomes to be known immediately, and half expected a week's delay. Known-risk games were generally preferred, confirming a significant strategic ambiguity aversion effect. In the delay conditions, players who knew that the ambiguous co-player types were equally likely were significantly less ambiguity averse than those who did not. Decision confidence was significantly higher in 2 × 2 than in larger games.     

Ambiguous games: evidence for strategic ambiguity aversion

The problem of ambiguity in games is discussed, and a class of ambiguous games is identified. A total of 195 participants played strategic-form games of various sizes with unidentified co-players. In each case, they first chose between a known-risk game involving a co-player indifferent between strategies and an equivalent ambiguous game involving one of several co-player types, each with a different dominant strategy, and then they chose a strategy for the preferred game. Half the players knew that the ambiguous co-player types were equally likely, and half did not. Half expected the outcomes to be known immediately, and half expected a week's delay. Known-risk games were generally preferred, confirming a significant strategic ambiguity aversion effect. In the delay conditions, players who knew that the ambiguous co-player types were equally likely were significantly less ambiguity averse than those who did not. Decision confidence was significantly higher in 2 × 2 than in larger games.     

From reasonable preferences,via argumentation,to logic

This article demonstrates that typical restrictions which are imposed in dialogical logic in order to recover first-order logical consequence from a fragment of natural language argumentation are also forthcoming from preference profiles of boundedly rational players, provided that these players instantiate a specific player type and compute partial strategies. We present two structural rules, which are formulated similarly to closure rules for tableaux proofs that restrict players' strategies to a mapping between games in extensive forms (i.e., game trees) and proof trees. Both rules are motivated from players' preferences and limitations; they can therefore be viewed as being player-self-imposable. First-order logical consequence is thus shown to result from playing a specific type of argumentation game. The alignment of such games with the normative model of the Pragma-dialectical theory of argumentation is positively evaluated. But explicit rules to guarantee that the argumentation game instantiates first-order logical consequence have now become gratuitous, since their normative content arises directly from players' preferences and limitations. A similar naturalization for non-classical logics is discussed.     

Message Exchange Games in Strategic Contexts

When two people engage in a conversation, knowingly or unknowingly, they are playing a game. Players of such games have diverse objectives, or winning conditions: an applicant trying to convince her potential employer of her eligibility over that of a competitor, a prosecutor trying to convict a defendant, a politician trying to convince an electorate in a political debate, and so on. We argue that infinitary games offer a natural model for many structural characteristics of such conversations. We call such games message exchange games, and we compare them to existing game theoretic frameworks used in linguistics—for example, signaling games—and show that message exchange games are needed to handle non-cooperative conversation. In this paper, we concentrate on conversational games where players’ interests are opposed. We provide a taxonomy of conversations based on their winning conditions, and we investigate some essential features of winning conditions like consistency and what we call rhetorical cooperativity. We show that these features make our games decomposition sensitive, a property we define formally in the paper. We show that this property has far-reaching implications for the existence of winning strategies and their complexity. There is a class of winning conditions (decomposition invariant winning conditions) for which message exchange games are equivalent to Banach- Mazur games, which have been extensively studied and enjoy nice topological results. But decomposition sensitive goals are much more the norm and much more interesting linguistically and philosophically.     

Macbeth and the Joystick: Evidence for moral cleansing after playing a violent video game

The “Macbeth effect” denotes the phenomenon that people wish to cleanse themselves physically when their moral self has been threatened. In this article we argue that such a threat to one's moral self may also result from playing a violent video game, especially when the game involves violence against humans. The cleansing effect should be particularly strong among inexperienced players who do not play video games on a regular basis, because frequent players may apply other strategies to alleviate any moral concerns. Seventy students played one of two violent video games and were then asked to select 4 out of 10 gift products, half of which were hygiene products. Inexperienced players reported more moral distress when the game involved violence against humans (compared to violence against objects), and selected more hygiene products in this condition than frequent video game players. Frequent players, on the other hand, reported less moral distress, irrespective of the game they played.     

Effects of game location, period, and quality of opposition in elite handball performances

The aims of the present study were to identify (i) home advantage in elite handball according to the quality of opponent, (ii) the game periods where the teams score more goals, and (iii) the game statistics associated with the teams' success according to the game's location. The sample comprised 480 regular season games (2007-2009) from the Spanish Professional Handball League. The goals scored and shot effectiveness (6 m, 7 m, 9 m and fast breaks) were analyzed for each 5-min. game period in games between players of balanced and unbalanced quality. The home advantage was 64%, with higher values (71%) in balanced and lower values (55%) in unbalanced games. The 5-min. game periods in which teams scored more goals were the last 5-min. period of each half, especially in the second half. The effectiveness was only different in shots closer to the goal (6 m), which supports the territoriality theory of home advantage.     

Cooperation, psychological game theory, and limitations of rationality in social interaction

Rational choice theory enjoys unprecedented popularity and influence in the behavioral and social sciences, but it generates intractable problems when applied to socially interactive decisions. In individual decisions, instrumental rationality is defined in terms of expected utility maximization. This becomes problematic in interactive decisions, when individuals have only partial control over the outcomes, because expected utility maximization is undefined in the absence of assumptions about how the other participants will behave. Game theory therefore incorporates not only rationality but also common knowledge assumptions, enabling players to anticipate their co-players' strategies. Under these assumptions, disparate anomalies emerge. Instrumental rationality, conventionally interpreted, fails to explain intuitively obvious features of human interaction, yields predictions starkly at variance with experimental findings, and breaks down completely in certain cases. In particular, focal point selection in pure coordination games is inexplicable, though it is easily achieved in practice; the intuitively compelling payoff-dominance principle lacks rational justification; rationality in social dilemmas is self-defeating; a key solution concept for cooperative coalition games is frequently inapplicable; and rational choice in certain sequential games generates contradictions. In experiments, human players behave more cooperatively and receive higher payoffs than strict rationality would permit. Orthodox conceptions of rationality are evidently internally deficient and inadequate for explaining human interaction. Psychological game theory, based on nonstandard assumptions, is required to solve these problems, and some suggestions along these lines have already been put forward.     

The effects of time pressure on chess skill: an investigation into fast and slow processes underlying expert performance

The ability to play chess is generally assumed to depend on two types of processes: slow processes such as search, and fast processes such as pattern recognition. It has been argued that an increase in time pressure during a game selectively hinders the ability to engage in slow processes. Here we study the effect of time pressure on expert chess performance in order to test the hypothesis that compared to weak players, strong players depend relatively heavily on fast processes. In the first study we examine the performance of players of various strengths at an online chess server, for games played under different time controls. In a second study we examine the effect of time controls on performance in world championship matches. Both studies consistently show that skill differences between players become less predictive of the game outcome as the time controls are tightened. This result indicates that slow processes are at least as important for strong players as they are for weak players. Our findings pose a challenge for current theorizing in the field of expertise and chess.     

网络游戏消费的影响因素

网络游戏消费研究日益受到研究者的关注。本文对网络游戏消费的影响因素进行了梳理。网络游戏消费的影响因素主要包括个体特征、网络游戏特征、社交特征、知觉特征和体验特征这五个方面。影响网络游戏消费的个体特征包括年龄、性别和人格;网络游戏特征包括游戏品质、服务质量、定制和创新;社会交往包括社交行为、社会资本和社会规范;知觉特征包括价值知觉、风险知觉、控制知觉,体验特征包括乐趣和心流。未来的研究应该关注不同品类网络游戏消费的影响因素的比较,消极社交互动以及与线上-线下社交迁移对网络游戏消费的影响。     

亲社会视频游戏中的合作对博弈决策中合作行为的影响

以38名大学生和研究生为被试,采用Chicken Game实验范式测量合作行为,考察了单人和双人合作模式游戏后,性别和游戏习惯对玩家在博弈决策中合作行为的影响。结果表明：（1）双人合作模式游戏可以促进玩家在博弈决策中的合作行为;（2）双人合作模式游戏后,男玩家（相比女玩家）在博弈决策中的合作行为更多;（3）玩游戏的习惯影响博弈决策中的合作行为,相比于经常习惯与现实朋友玩游戏和独自玩游戏的玩家,经常习惯与网友玩游戏的玩家在双人合作模式游戏后的合作行为更多。本研究不仅证实了一般学习模型,也证实了亲社会合作类视频游戏可以有效促进博弈决策中的合作行为。     

Real brands in imaginary worlds: investigating players' experiences of brand placement in digital games

• This paper explores the development of brand placement in digital games using focus groups with game‐players. Growth in in‐game brand placement is explained by game developers' financial and creative priorities and experimentation in marketerss' use of media. The external context of game‐play is then examined based on explanations of the non‐material aspects of consumer behaviour. Internal game processes are also reviewed, including psychological processes that are likely to be of interest to marketers. The reported experiences of players are then considered in terms of these processes. Findings seem to support the use of brand placement in games. Players easily recall encounters with brands during game‐play and are generally positive about these experiences, suggesting that brands increase realism because it allows individuals to create and explore consumption‐based daydreams. However, some players reject brand placement, preferring in‐game fantasies that are independent of mundane commodities. The findings also raise issues related to the ways in which individuals may use digital games to reflect on our consumer society and this raises a question of the degree to which digital games may support or oppose existing consumer cultures. Other problems for managers wishing to use this technique were revealed by the repetitive nature of games which may cause message wear‐out, and by playerss' frustration with aspects of a game which may lead to negative evaluations of in‐game brands.

Copyright © 2006 John Wiley & Sons, Ltd.     

Appetitive and Defensive Arousal in Violent Video Games: Explaining Individual Differences in Attraction to and Effects of Video Games

Evidence surrounding the attraction to media violence is mixed and the effects of violent video game play on players varies across experimental participants. Differences in both may be explained by differences in experienced positive or negative arousal. This study utilizes the limited capacity model of motivated mediated message processing (LC4MP) and the motivation activation measure (MAM), which measures resting activation of the appetitive and aversive arousal systems, to explore the relationship between attraction to media violence, arousal, and aggression. In part 1, a questionnaire found that men and frequent players of violent games expected to enjoy violent games more than nonviolent games. In addition, participants whose scores on the MAM characterized them as risk takers (high scores on appetitive arousal and low scores on aversive arousal) indicated a stronger preference for violent games compared to the other three arousal types, which is in line with the LC4MP. In the experimental portion of the research, after playing a violent game, those participants characterized as risk avoidant (high on aversive arousal and low on appetitive arousal) were significantly less aggressive than all other arousal groups. Overall, results show that individual differences in the appetitive and aversive arousal systems can explain attraction to violent media. Furthermore, arousal resulting from violent video game play can be experienced as pleasant or aversive, and it is this experience of arousal that explains variations in aggressive responses to violent video games.     

Game Theory in Philosophy

Game theory is the mathematical study of strategy and conflict. It has wide applications in economics, political science, sociology, and, to some extent, in philosophy. Where rational choice theory or decision theory is concerned with individual agents facing games against nature, game theory deals with games in which all players have preference orderings over the possible outcomes of the game. This paper gives an informal introduction to the theory and a survey of applications in diverse branches of philosophy. No criticism is reviewed. Game theory is shown at work in discussions about epistemological dependence (prisoner’s dilemma), liberalism and efficiency (Nash equilibrium), Hume’s concept of convention (correlated equilibrium), morality and rationality (bargaining games), and distributive justice and egalitarianism (evolutionary game theory). A guide to the literature provides hints at applications in collective intentionality, epistemology, ethics, history of philosophy, logic, philosophy of language, and political philosophy.