共查询到20条相似文献,搜索用时 31 毫秒
1.
In the article, a yes–no model of influence is generalized to a multi-choice framework. We introduce and study the weighted
influence indices of a coalition on a player in a social network where the players have an ordered set of possible actions.
Each player has an inclination to choose one of the actions. Due to the mutual influence among players, the final decision
of each player may be different from his original inclination. In a particular case, the decision of the player is closer
to the inclination of the influencing coalition than his inclination was, i.e., the distance between the inclinations of the
player and of the coalition is greater than the distance between the decision of the player and the inclination of the coalition
in question. The weighted influence index which captures such a case is called the weighted positive influence index. We also
consider the weighted negative influence index where the final decision of the player goes farther away from the inclination
of the coalition. We consider several influence functions defined in the generalized model of influence and study their properties.
The concept of a follower of a given coalition and its particular case, a perfect follower, are defined. The properties of
the set of followers are analyzed. 相似文献
2.
In certain judgmental situations where a “correct” decision is presumed to exist, optimal decision making requires evaluation
of the decision-makers’ capabilities and the selection of the appropriate aggregation rule. The major and so far unresolved
difficulty is the former necessity. This article presents the optimal aggregation rule that simultaneously satisfies these
two interdependent necessary requirements. In our setting, some record of the voters’ past decisions is available, but the
correct decisions are not known. We observe that any arbitrary evaluation of the decision-makers’ capabilities as probabilities
yields some optimal aggregation rule that, in turn, yields a maximum-likelihood estimation of decisional skills. Thus, a skill-evaluation equilibrium can be defined as an evaluation of decisional skills that yields itself as a maximum-likelihood estimation of decisional
skills. We show that such equilibrium exists and offer a procedure for finding one. The obtained equilibrium is locally optimal
and is shown empirically to generally be globally optimal in terms of the correctness of the resulting collective decisions.
Interestingly, under minimally competent (almost symmetric) skill distributions that allow unskilled decision makers, the
optimal rule considerably outperforms the common simple majority rule (SMR). Furthermore, a sufficient record of past decisions
ensures that the collective probability of making a correct decision converges to 1, as opposed to accuracy of about 0.7 under
SMR. Our proposed optimal voting procedure relaxes the fundamental (and sometimes unrealistic) assumptions in Condorcet’s
celebrated theorem and its extensions, such as sufficiently high decision-making quality, skill homogeneity or existence of
a sufficiently large group of decision makers. 相似文献
3.
Professionals encountering possible cases of child neglect facea complex task when judging whether a particular concern warrantsa referral to social work services. A study of referral practicein cases of child neglect, completed in the Republic of Ireland,highlighted that it is not just the nature of the concern thatinfluences referral practice but a range of other factors thatare not related to the needs of the specific child. Assessmentframeworks and tools, designed to assist practitioners makedecisions about potential cases of neglect, usually focus ontechnical–rational activity associated with assessingchildrens needs, parenting capacity and family and environmentalfactors. The findings from the study described in this paperindicate that assessment practice is as much a practice–moralactivity as a technical–rational one. In other words,it is both a head and a heart activity. In this article, thefactors influencing practitioners approaches to the identificationand referral of cases of child neglect are explored. A rangeof factors appear to influence practice. These include the practitionersown perception of what comprises neglect and the extent to whichthey use gut reaction or an evidence base to reachthis conclusion. Their interpretation of role and the viewsof their colleagues and team manager also influence practice.In addition, their perception of social work services and thebenefits of referral affect decisions to refer. Finally, theirown personal feelings such as fear, guilt, over-empathy andanxiety about the response of the community have an effect onpractice. The paper concludes by drawing together the findingsof the study to produce a practitioner domainalerting practitioners and managers to the head and heart activitieswhich influence referral practice. 相似文献
4.
Consider a simple game with n players. Let ψi be the Shapley–Shubik power index for player i. Then 1-ψi measures his powerlessness. We break down this powerlessness into two components – a `quixote index' Q
i (which measures how much of a `quixote' i is), and a `follower index' F
i (which measures how much of a `follower' he is). Formulae, properties, and axiomatizations for Q and F are given. Examples are also supplied.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
5.
Power indices are commonly required to assign at least as much power to a player endowed with some given voting weight as
to any player of the same game with smaller weight. This local monotonicity and a related global property however are frequently
and for good reasons violated when indices take account of a priori unions amongst subsets of players (reflecting, e.g., ideological
proximity). This paper introduces adaptations of the conventional monotonicity notions that are suitable for voting games
with an exogenous coalition structure. A taxonomy of old and new monotonicity concepts is provided, and different coalitional
versions of the Banzhaf and Shapley–Shubik power indices are compared accordingly.
相似文献
6.
Hagen Lindstädt 《Theory and Decision》2007,62(4):335-353
Sometimes we believe that others receive harmful information. However, Marschak’s value of information framework always assigns
non-negative value under expected utility: it starts from the decision maker’s beliefs – and one can never anticipate information’s
harmfulness for oneself. The impact of decision makers’ capabilities to process information and of their expectations remains
hidden behind the individual and subjective perspective Marschak’s framework assumes. By introducing a second decision maker
as a point of reference, this paper introduces a way for evaluating others’ information from a cross-individual, imperfect
expectations perspective for agents maximising expected utility. We define the cross-value of information that can become negative – then the information is “harmful” from a cross-individual perspective – and we define (mutual) cost of limited information processing capabilities and imperfect expectations as an opportunity cost from this same point of reference. The simple relationship between these two expected utility-based
concepts and Marschak’s framework is shown, and we discuss evaluating short-term reactions of stock market prices to new information
as an important domain of valuing others’ information.
相似文献
7.
André Casajus 《Theory and Decision》2011,71(2):163-174
We revisit the characterization of the Shapley value by van den Brink (Int J Game Theory, 2001, 30:309–319) via efficiency,
the Null player axiom, and some fairness axiom. In particular, we show that this characterization also works within certain
classes of TU games, including the classes of superadditive and of convex games. Further, we advocate some differential version
of the marginality axiom (Young, Int J Game Theory, 1985, 14: 65–72), which turns out to be equivalent to the van den Brink
fairness axiom on large classes of games. 相似文献
8.
We study political influence in institutions where each member chooses a level of support for a collective goal. These individual
choices determine the degree to which the goal is reached. Influence is assessed by newly defined binary relations, each of
which ranks members on the basis of their relative performance at a corresponding level of participation. For institutions
with three options (e.g., voting games in which each voter may vote “yes”, “abstain”, or vote “no”), we obtain three influence
relations, and show that their strict components may be cyclic. This latter property describes a “paradox of power” which
contrasts with the transitivity of the unique influence relation of binary voting games. Weak conditions of anonymity suffice
for each of these relations to be transitive. We also obtain a necessary and sufficient condition for each of these relations
to be complete. Further, we characterize institutions in which the rankings induced by these relations, and the Banzhaf–Coleman
and Shapley–Shubik power indices coincide. We argue that extending the influence relations to firms would be useful in efficiently
assigning workers to different units of production. Finally, we provide applications to various forms of political and economic
organizations. 相似文献
9.
This paper introduces the likelihood method for decision under uncertainty. The method allows the quantitative determination
of subjective beliefs or decision weights without invoking additional separability conditions, and generalizes the Savage–de
Finetti betting method. It is applied to a number of popular models for decision under uncertainty. In each case, preference
foundations result from the requirement that no inconsistencies are to be revealed by the version of the likelihood method
appropriate for the model considered. A unified treatment of subjective decision weights results for most of the decision
models popular today. Savage’s derivation of subjective expected utility can now be generalized and simplified. In addition
to the intuitive and empirical contributions of the likelihood method, we provide a number of technical contributions: We
generalize Savage’s nonatomiticy condition (“P6”) and his assumption of (sigma) algebras of events, while fully maintaining
his flexibility regarding the outcome set. Derivations of Choquet expected utility and probabilistic sophistication are generalized
and simplified similarly. The likelihood method also reveals a common intuition underlying many other conditions for uncertainty,
such as definitions of ambiguity aversion and pessimism. 相似文献
10.
Alexander Zimper 《Theory and Decision》2011,71(4):669-677
Yoo (Economic Letters 37:145–149, 1991) argues that the law of iterated expectations must be violated if the probability measure
of a Choquet decision maker is non-additive. In this article, we prove the positive result that the law of iterated expectations
is satisfied for Choquet decision makers whenever they update their non-additive beliefs in accordance with the Sarin and
Wakker (Journal of Risk and Uncertainty 16:223–250, 1998) update rule. The formal key to this result is the act-dependence
of the Sarin–Wakker update rule, which does not hold for the update rules considered by Yoo (1991). 相似文献
11.
Ranking finite subsets of a given set X of elements is the formal object of analysis in this article. This problem has found a wide range of economic interpretations
in the literature. The focus of the article is on the family of rankings that are additively representable. Existing characterizations
are too complex and hard to grasp in decisional contexts. Furthermore, Fishburn (1996), Journal of Mathematical Psychology
40, 64–77 showed that the number of sufficient and necessary conditions that are needed to characterize such a family has
no upper bound as the cardinality of X increases. In turn, this article proposes a way to overcome these difficulties and allows for the characterization of a meaningful
(sub)family of additively representable rankings of sets by means of a few simple axioms. Pattanaik and Xu’s (1990), Recherches
Economiques de Louvain 56, 383–390) characterization of the cardinality-based rule will be derived from our main result, and other new rules that stem from our general proposal are discussed and characterized
in even simpler terms. In particular, we analyze restricted-cardinality based rules, where the set of “focal” elements is
not given ex-ante; but brought out by the axioms.
相似文献
12.
13.
Game trees (or extensive-form games) were first defined by von Neumann and Morgenstern in 1944. In this paper we examine the use of game trees for representing Bayesian decision problems. We propose a method for solving game trees using local computation. This method is a special case of a method due to Wilson for computing equilibria in 2-person games. Game trees differ from decision trees in the representations of information constraints and uncertainty. We compare the game tree representation and solution technique with other techniques for decision analysis such as decision trees, influence diagrams, and valuation networks. 相似文献
14.
15.
Expected Utility Consistent Extensions of Preferences 总被引:1,自引:1,他引:0
We consider the problem of extending a (complete) order over a set to its power set. The extension axioms we consider generate
orderings over sets according to their expected utilities induced by some assignment of utilities over alternatives and probability
distributions over sets. The model we propose gives a general and unified exposition of expected utility consistent extensions
whilst it allows to emphasize various subtleties, the effects of which seem to be underestimated – particularly in the literature
on strategy-proof social choice correspondences.
相似文献
16.
Bertrand Munier 《Theory and Decision》1989,27(1-2):93-106
In the first part, we try to give a representation of the process by which man endeavours to grasp uncertainty. We propose a backward exploration which we will modelize through an influence diagram and then we can draw a few conclusions from that representation for the axiomatics of Decision.In the second part, we deal with the processing of the information formatted in such a way, regarding both its temporal complexity and its elective complexity.The first part as the second one dealing with representation and the consequences for information processing of uncertainty cognition lead to a severe criticism of the expected utility hypothesis.To conclude, we suggest a few remarks on expert systems of decision aid under uncertainty. 相似文献
17.
Kjell Hausken 《Theory and Decision》2007,62(2):135-160
Axelord’s [(1970), Conflict of Interest, Markham Publishers, Chicago] index of conflict in 2 × 2 games with two pure strategy equilibria has the property that a
reduction in the cost of holding out corresponds to an increase in conflict. This article takes the opposite view, arguing
that if losing becomes less costly, a player is less likely to gamble to win, which means that conflict will be less frequent.
This approach leads to a new power index and a new measure of stubbornness, both anchored in strategic reasoning. The win
probability defined as power constitutes an equilibrium refinement which differs from Harsanyi and Selten’s [(1988), A General Theory of Equilibrium Selection in Games, MIT Press, Cambridge] refinement. In contrast, Axelrod’s approach focuses on preferences regarding divergences from imaginary
outmost rewards that cannot be obtained jointly. The player who is less powerful in an asymmetric one-shot game becomes more
powerful in the repeated game, provided he or she values the future sufficiently more than the opponent. This contrasts with
the view that repetition induces cooperation, but conforms with the expectation that a more patient player receives a larger
share of the pie.
相似文献
18.
What are the minimal requirements of rational choice? Arguments from the sequential-decision setting
Katie Siobhan Steele 《Theory and Decision》2010,68(4):463-487
There are at least two plausible generalisations of subjective expected utility (SEU) theory: cumulative prospect theory (which
relaxes the independence axiom) and Levi’s decision theory (which relaxes at least ordering). These theories call for a re-assessment
of the minimal requirements of rational choice. Here, I consider how an analysis of sequential decision making contributes
to this assessment. I criticise Hammond’s (Economica 44(176):337–350, 1977; Econ Philos 4:292–297, 1988a; Risk, decision and
rationality, 1988b; Theory Decis 25:25–78, 1988c) ‘consequentialist’ argument for the SEU preference axioms, but go on to
formulate a related diachronic-Dutch-book-style’ argument that better achieves Hammond’s aims. Some deny the importance of
Dutch-book sure losses, however, in which case, Seidenfeld’s (Econ Philos 4:267–290, 1988a) argument that distinguishes between
theories that relax independence and those that relax ordering is relevant. I unravel Seidenfeld’s argument in light of the
various criticisms of it and show that the crux of the argument is somewhat different and much more persuasive than what others
have taken it to be; the critical issue is the modelling of future choices between ‘indifferent’ decision-tree branches in
the sequential setting. Finally, I consider how Seidenfeld’s conclusions might nonetheless be resisted. 相似文献
19.
Ilia Tsetlin 《Theory and Decision》2006,61(1):51-62
Designing a mechanism that provides a direct incentive for an individual to report her utility function over several alternatives
is a difficult task. A framework for such mechanism design is the following: an individual (a decision maker) is faced with
an optimization problem (e.g., maximization of expected utility), and a mechanism designer observes the decision maker’s action.
The mechanism does reveal the individual’s utility truthfully if the mechanism designer, having observed the decision maker’s
action, infers the decision maker’s utilities over several alternatives. This paper studies an example of such a mechanism
and discusses its application to the problem of optimal social choice. Under certain simplifying assumptions about individuals’
utility functions and about how voters choose their voting strategies, this mechanism selects the alternative that maximizes
Harsanyi’s social utility function and is Pareto-efficient. 相似文献
20.
Jörg Stoye 《Theory and Decision》2011,70(2):129-148
This article provides unified axiomatic foundations for the most common optimality criteria in statistical decision theory.
It considers a decision maker who faces a number of possible models of the world (possibly corresponding to true parameter
values). Every model generates objective probabilities, and von Neumann–Morgenstern expected utility applies where these obtain,
but no probabilities of models are given. This is the classic problem captured by Wald’s (Statistical decision functions,
1950) device of risk functions. In an Anscombe–Aumann environment, I characterize Bayesianism (as a backdrop), the statistical
minimax principle, the Hurwicz criterion, minimax regret, and the “Pareto” preference ordering that rationalizes admissibility.
Two interesting findings are that c-independence is not crucial in characterizing the minimax principle and that the axiom
which picks minimax regret over maximin utility is von Neumann–Morgenstern independence. 相似文献