A new typology of players is proposed based on the classification of actions as either instinctive or contemplative. A person’s type is the probability of him choosing a contemplative action. To test the typology, results of 10 games are analyzed. Actions in each game were classified depending on whether their response time was more or less, respectively, than the median response time of all subjects who played the game. It is argued that fast actions are more instinctive and slow actions are more contemplative. A subject’s contemplative index (CI) is defined as the proportion of games in which he chose a contemplative action. It is found that for 8 of the 10 games, the CI in the other 9 games is positively correlated with a player’s choice of a contemplative action in that game (average Spearman correlation of 9%). The CI is used to shed light on the nature of choice in five additional games.

The aim of this paper is to explain the fact that certain properties of binary relations are frequently observed in natural language while others do not appear at all. Three features of binary relation are studied: (1) The ability to use the relation to indicate nameless elements. (2) The accuracy with which the vocabulary spanned by the relation can be used to approximate the actual terms to which a user of the language wishes to refer. (3) The ease with which the relation can be described by means of examples. It is argued that linear orderings are optimal according to the first criteria while asymmetric relations are optimal according to second. From among complete and asymmetric relations (tournaments) those which are transitive are optimal according to the third criterion.

The paper is a discussion of the interpretation of game theory. The first half of the paper deals with the notion of "strategy". The paper endorses the view that equilibrium strategy describes a player's plan of action, as well as those considerations which support the optimality of his plan rather than being merely described as a "plan of action". In the second half of the paper it is argued that a good model in game theory has to be realistic in the sense that it provides a model for the perception of real life social phenomena. It should incorporate a description of the relevant factors involved, as perceived by the decision makers.

Etude d'un jeu de negociation strategique sequentiel avec information incomplete. Caracterisation d'une classe d'equilibres sequentiels appeles equilibres sequentiels de negociation et demonstration de l'unicite de cet equilibre

Focuses on a study which examined perfect equilibrium in a bargaining model. Overview of the strategic approach adopted for the study; Details of the bargaining situation used; Discussion on perfect equilibrium. (From Ebsco)

For a market with a finite number of agents, pairwise matching and bargaining, it is shown that, even when the market is frictionless, the equilibrium is not necessarily competitive. It depends on the amount of information agents use. If their behaviour is conditioned only on the sets of agents present and the time, the competitive solution is the unique subgame perfect equilibrium. If agents have full information and condition their behaviour on some of it, there are also noncompetitive equilibria in which behaviour depends on specific information such as the identity of the trading partner and past events.

We study a model of a market with three types of agents: sellers, buyers, and middlemen. Buyers and sellers can trade directly or indirectly through the middlemen. The analysis focuses on steady state situations in which the numbers of agents of the different types and hence the trading opportunities are constant over time. The paper provides a framework for analyzing the activity of middlemen and the endogenous determination of the extent of that activity. It highlights the relations between the trading procedure and the distribution of the gains from trade.