Coalition formation in characteristic function games: Competitive tests of three theories

Two experiments tested the bargaining, minimum resource, and minimum power theories of coalition formation in situations involving different payoffs for some of the winning coalitions (characteristic function games). In the first experiment, a triadic resource distribution was employed and payoffs for the coalitions were specified in such a way that each of the three theories predicted the formation of a different coalition. The coalition predicted by minimum power theory formed the most frequently, and the mean divisions of the payoffs among coalition members were also closest to the predictions of minimum power theory. However, the most frequent coalition was not only the one predicted by minimum power theory, it was also the one having the largest payoff per member. There-fore, a second experiment was conducted, which employed a tetradic resource distribution and specified the coalition payoffs in such a way that (a) each of the theories predicted the formation of a different coalition and (b) none of the predicted coalitions was the one with the largest payoff per member. Although the mean payoff divisions in the coalitions in this experiment were closest to those predicted by bargaining theory, the coalition that formed most frequently was not one of those predicted by any of the theories. Rather, it was the one having the largest payoff per member. None of the three theories is able to account adequately for the results of both experiments. The difficulties that the theories have in dealing with coalition formation in situations in which there are different payoffs for winning are discussed.     

Can intergroup behaviors be emitted out of self-determined reasons? Testing the role of group norms and behavioral congruence in the internalization of discrimination and parity behaviors

Bringing self-determination theory to understand why intergroup behaviors are emitted, two studies were conducted to investigate how group norms and individuals' congruence with these norms predicted self-determination to pursue two types of intergroup behaviors (parity and discrimination). Experiment 1 (N = 97) manipulated ingroup norms in favor of parity versus of discrimination and assessed the behavior participants displayed (congruent or incongruent with the norm) and their motivations for emitting this behavior. The manipulated norms significantly influenced group members' behaviors. When the ingroup norm was parity, participants whose behavior was congruent with this norm reported more self-determination to emit this behavior. When the ingroup norm was prodiscrimination, participants whose behavior was congruent with this norm were less self-determined. Experiment 2 (N = 139) replicated and extended these findings in a more conflictual intergroup setting. Results are discussed in light of motivational and intergroup theories.     

The role of objects in perceptual grouping.

Perceptual organization can be viewed as the selection of the best or "most reasonable" parse of a given scene. However, the principles that determine which interpretation is most reasonable have resisted most attempts to define them formally. This paper summarizes a formal theory of human perceptual organization, called minimal model theory, in which the best interpretation of a given scene is expressed as the formally minimal interpretation in a well-defined space of possible interpretations. We then focus specifically on the role of types of grouping units, in particular the difficult notion of "object". Although grouping is often thought of as the process of dividing the image into objects, most research in perceptual grouping actually focuses on simpler types of units, such as contours and surfaces. Minimal model theory characterizes grouping units at a logical level, demonstrating how formal assumptions about units induce the observer to place a certain preference ranking on interpretations. The theory is then applied to the more subtle problem of objects, culminating in a definition for objects that is formally rigorous but at the same time captures some of the flexibility of human intuitions about objects.     

The Birth of Social Choice Theory from the Spirit of Mathematical Logic: Arrow’s Theorem in the Framework of Model Theory

Arrow’s axiomatic foundation of social choice theory can be understood as an application of Tarski’s methodology of the deductive sciences—which is closely related to the latter’s foundational contribution to model theory. In this note we show in a model-theoretic framework how Arrow’s use of von Neumann and Morgenstern’s concept of winning coalitions allows to exploit the algebraic structures involved in preference aggregation; this approach entails an alternative indirect ultrafilter proof for Arrow’s dictatorship result. This link also connects Arrow’s seminal result to key developments and concepts in the history of model theory, notably ultraproducts and preservation results.     

Strength-is-Weakness: The (ir)relevant relation between resources and payoffs in coalition formation

A key observation in coalition formation is that bargainers who control many resources are often excluded from coalitions by bargainers who control few resources, the Strength-is-Weakness effect. We argue that this effect is contingent on whether resources provide a legitimate claim to be included in a coalition. Across three incentivized coalition experiments (n = 2745; 915 triads), three participants (player A had four resources, player B had three resources, player C had two resources) negotiated about a payoff of 90 monetary units. Depending on condition, these resources were obtained randomly, earned, or earned and proportionally linked to the payoff. Results showed player As were less included when resources were obtained randomly and more often included in coalitions when resources were earned and/or proportionally linked to the payoff. This provides evidence that the Strength-is-Weakness is contingent on the legitimacy of the resources.     

Can harmful intergroup behaviors truly represent the self?: The impact of harmful and prosocial normative behaviors on intra-individual conflict and compartmentalization

This research investigates how group members subjectively feel about their prosocial vs. harmful intergroup behaviors, and whether these behaviors can represent who they are more globally as a person. Three experiments tested how group norms (pro-merit/parity vs. pro-discrimination) and congruence with these norms predicted compartmentalization of these intergroup behaviors in the self and intra-individual conflict. Experiment 1 (N = 122) revealed that participants who conformed to a pro-discrimination norm reported compartmentalizing this behavior to a greater extent than participants who conformed to a pro-merit norm. Experiments 2 (N = 149) and 3 (N = 222) replicated and extended these findings in real and conflictual intergroup settings, also over and above the effect of relevant superordinate norms. Mediated moderation analyses also revealed that following discriminatory norms was associated with more intra-individual conflict, and that this conflict in turn predicted higher compartmentalization.     

The Paradoxes and Promise of Community Coalitions

Community coalitions, as they are currently applied, are unique organizations whose ability to promote community change is different from other types of community organizations. This article explores those differences and elaborates how community coalitions can use those differences to transform conflict into greater capacity, equity, and justice. Concerns are also raised in this article about how community coalitions can intentionally and unintentionally protect the status quo and contain the empowerment of grassroots leadership and those of marginalized groups. There is a need for more theory, research, and discourse on how community coalitions can transform conflict into social change and how they can increase the power of grassroots and other citizen-lead organizations.     

Quota vs positional power in four-person apex games

In coalition formation experiments, which coalitions will form and how players in coalitions will allocate their jointly gained rewards are typically predicted as a function of the players' relative power. In this paper, we isolated two logically independent sources of a player's power: the player's contribution to the rewards obtainable by coalitions of which he may be a member (“quota power”), and the number of distinct coalitions which a player may join (“positional power”). The separation of the two types of power is clearly shown in apex games, where a single player (Apex) attempts to lure any of the other players (Base) from the coalition of all Bases. A series of four-person computer-controlled apex and nonapex characteristic function games, varying with respect to the relationship of quota power to positional power, were played by 15 quartets of male players. Quota power was strongly manifested in all outcome measures, while positional power appeared only as a bias toward equal allocations of reward when coalitions among players of equal positional power formed. Neither of two social psychological theories that are applicable, pivotal power and weighted probability theory, predicted coalition frequencies. In a test of five solution concepts, the competitive bargaining set predicted payoff allocations better than either of the two aforementioned theories, the kernel, or an equal-split model.     

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.     

Conflicting Intuitions about Causality1

In this article I examine five kinds of conflicting intuitions about the nature of causality. The viewpoint is that of a probabilistic theory of causality, which I think is the right general framework for examining causal questions. It is not the purpose of this article to defend the general thesis in any depth but many of the particular points I make are meant to offer new lines of defense of such a probabilistic theory. To provide a conceptual framework for the analysis, I review briefly the more systematic aspects of the sort of probabilistic theory of causality I advocate. I first define the three notions of prima facie cause, spurious cause, and genuine cause. The technical details are worked out in an earlier monograph (Suppes 1970) and are not repeated.     

Cognitive-experiential self-theory and subjective probability: further evidence for two conceptual systems.

Three experiments (N = 1,331) demonstrated that research findings on suspiciousness about coincidences (Miller, Turnbull, & McFarland, 1989) can be accounted for in terms of subjective probability, as predicted by cognitive-experiential self-theory (CEST) but in contrast with the norm theory (NT) account offered by Miller et al. (1989). Ss participated in a hypothetical (Experiments 1 and 2) or real (Experiment 3) lottery game in which they chose between 2 bowls offering equivalent probabilities of winning or losing but differing with respect to absolute numbers (e.g., 1 in 10 vs. 10 in 100). Responses across 4 conditions (2 probability levels x 2 outcome types) and across the 3 experiments supported predictions derived from CEST but not those derived from NT. Results are discussed in terms of 2 conceptual systems, rational and experiential, that operate by different rules of inference.     

Are people excessive or judicious in their egocentrism? A modeling approach to understanding bias and accuracy in people's optimism

People are often egocentric when judging their likelihood of success in competitions, leading to overoptimism about winning when circumstances are generally easy and to overpessimism when the circumstances are difficult. Yet, egocentrism might be grounded in a rational tendency to favor highly reliable information (about the self) more so than less reliable information (about others). A general theory of probability called extended support theory was used to conceptualize and assess the role of egocentrism and its consequences for the accuracy of people's optimism in 3 competitions (Studies 1-3, respectively). Also, instructions were manipulated to test whether people who were urged to avoid egocentrism would show improved or worsened accuracy in their likelihood judgments. Egocentrism was found to have a potentially helpful effect on one form of accuracy, but people generally showed too much egocentrism. Debias instructions improved one form of accuracy but had no impact on another. The advantages of using the EST framework for studying optimism and other types of judgments (e.g., comparative ability judgments) are discussed.     

The Duty to Rescue and the Limits of Confidentiality

Surveys and routine clinical procedures applied in research protocols are typically considered only minimally risky to participants. The apparent benign nature of "minimal risk" tasks increases the chance that investigators and Institutional Review Boards (IRBs) will overlook the probability that clinical tools will identify signs, symptoms, or definitive test results that are clinically-relevant to subjects' welfare. "Minimal risk" procedures may also pose a particular hazard to participants in clinical research by increasing the therapeutic misconception because the tasks mimic clinical care and are often conducted in clinical settings. Investigators should anticipate which measures could yield clinically-important findings and should describe explicit plans for data monitoring, disclosure, and follow-up. Protocols that include reliable and valid clinical measures should prompt a more detailed risk assessment by the IRB, even when the tasks meet the regulatory criteria for minimal physical, psychological, or emotional risk.     

An experimental test of a game‐theoretical model of reciprocity

In this contribution the norm of reciprocity is defined as a basic internal motivation. Using formal tools of game theory, a model of social utility function is presented. The reciprocity model predicts that social actors should reciprocate costs and benefits they receive, even when there are costs in conforming to the norm. Hypotheses about actors' behavior, expectations and evaluations are derived from the model. The hypotheses were tested in an experimental situation, the reciprocity game, consisting of a prisoner's dilemma game (PD) followed by a dictator game (DG). The sample was composed of 74 Italian undergraduate students. In line with the model's predictions, the experimental results showed that participants reciprocate the behavior of the opponent in the PD. In the DG, if the opponent cooperated, participants gave back an almost equal share, whereas if the opponent defected, participants gave a minimal amount. These reciprocity effects are modulated by individual differences in the concern for reciprocity. Copyright © 2000 John Wiley & Sons, Ltd.     

Peaking at the right time: Perceptions,expectations, and effects

We explore the concept of peaking at the right time. Study 1 is a content analysis of 325 National Football League articles identifying four key triggers that prompt proclamations of peaking at the right time: turnarounds, impressive prior events, winning streaks, and out-ofs. Study 2 experimental results reveal that turnarounds most strongly impact perceptions of peaking at the right time, anticipated performance, and expectations faced. However, nuanced differences occur across two time periods during the season. Studies 1 and 2 also indicate that observers expect teams to win their next games more often than actually happens. Study 3 demonstrates that teams prepare harder and make riskier game plans when their next opponent is peaking at the right time. Study 4 suggests that individuals more strongly desiring to peak at the right time than others will value various factors differently at different time points when envisioning upcoming seasons.     

Minimal Truthmakers

A minimal truthmaker for a given proposition is the smallest portion of reality which makes this proposition true. Minimal truthmakers are frequently mentioned in the literature, but there has been no systematic account of what they are or of their importance. In this article we shall clarify the notion of a minimal truthmaker and argue that there is reason to think that at least some propositions have minimal truthmakers. We shall then argue that the notion can play a useful role in truthmaker theory, by helping to explain the truth of certain propositions as precisely as possible.     

Cerebral Asymmetry and Decision Strategies in Mental Rotation: A Psychophysical Analysis

The accuracy with which observers judged the parity of pairs of rotated images in the two visual fields was determined from receiver operating characteristic (ROC) analysis of confidence ratings. In one experiment, observers judged whether pairs of letters were of the same parity (that is, both normal or both backwards) or of different parities (one normal and one backwards). A small right visual field advantage in the observers' accuracy was found in this mental rotation task. In a second experiment, observers judged whether pairs of pictures were of the same parity or of different parities. Unlike the first experiment, no evidence of a consistent visual field advantage was found in this mental rotation task. The decision strategy adopted by the observers in making same-different judgements about rotated stimuli was examined. The symmetrical shape of the ROCs obtained was consistent with the adoption of the likelihood-ratio decision strategy, a result which supplemented previous evidence that this decision strategy is adopted when same-different judgements are made about multidimensional stimuli.     

Extended Cognition and Propositional Memory

The philosophical case for extended cognition is often made with reference to ‘extended‐memory cases’ (e.g. Clark & Chalmers 1998); though, unfortunately, proponents of the hypothesis of extended cognition (HEC) as well as their adversaries have failed to appreciate the kinds of epistemological problems extended‐memory cases pose for mainstream thinking in the epistemology of memory. It is time to give these problems a closer look. Our plan is as follows: in §1, we argue that an epistemological theory remains compatible with HEC only if its epistemic assessments do not violate what we call ‘the epistemic parity principle’. In §2, we show how the constraint of respecting the epistemic parity principle stands in what appears to be a prima facie intractable tension with mainstream thinking about cases of propositional memory. We then outline and evaluate in §3 several lines of response.