Abstract not found

A usual criticism of the theory of infinitely repeated games is that it does not provide sharp predictions since there may be a multiplicity of equilibria. To address this issue we present experimental evidence on the evolution of cooperation in infinitely repeated prisoners ’ dilemma games as subjects gain experience. We find that cooperation decreases with experience when it cannot be supported as an equilibrium outcome. More interestingly, the converse is not necessarily true: cooperation does not always increase with experience when it can be supported as an equilibrium outcome. Nor is a more stringent condition, risk dominance, sufficient for cooperation to arise. However, subjects do learn to cooperate when the payoff to cooperation and the importance of the future is high enough. These results have important implications for the theory of infinitely repeated games. While we show that cooperation may prevail in infinitely repeated games, the conditions under which this occurs are more stringent than the sub-game

Computer systems increasingly carry out tasks in mixed networks, that is in group settings in which they interact both with other computer systems and with people. Participants in these heterogeneous human-computer groups vary in their capabilities, goals, and strategies; they may cooperate, collaborate, or compete. The presence of people in mixed networks raises challenges for the design and the evaluation of decision-making strategies for computer agents. This paper describes several new decision-making models that represent, learn and adapt to various social attributes that influence people’s decision-making and presents a novel approach to evaluating such models. It identifies a range of social attributes in an open-network setting that influence people’s decision-making and thus affect the performance of computeragent strategies, and establishes the importance of learning and adaptation to the success of such strategies. The settings vary in the capabilities, goals, and strategies that people bring into their interactions. The studies deploy a configurable system called Colored Trails (CT) that generates a family of games. CT is an abstract, conceptually simple but highly versatile game in which players negotiate and exchange resources to enable them to achieve their individual or group goals. It provides a realistic analogue to multi-agent task than payoff matrices, and people exhibit less strategic and more helpful behavior in CT than in the identical payoff matrix decision-making context. By not requiring extensive domain modeling, CT enables agent researchers to focus their attention on strategy design, and it provides an environment in which the influence of social factors can be better isolated and studied.

Abstract not found

This paper attempts to bring some central insights from behavioural economics into the economics of climate change. In particular, it discusses (i) implications of prospect theory, the equity premium puzzle and time inconsistent preferences in the choice of discount rate used in climate change cost assessments, and (ii) the implications of various kinds of social preferences for the outcome of climate negotiations. Several reasons are presented for why it appears advisable to choose a substantially lower social discount rate than the average return on investments. It also seems likely that taking social preferences into account increases the possibilities of obtaining international agreements, compared to the standard model. However, there are also effects going in the opposite direction, and the importance of sanctions is emphasised.

Evidence suggests participants in games may evaluate invasive technologies differently. Accordingly, special care ought to be taken with the use of video games as research instruments. We propose a range of methods which help protect participants of video game experiments.

How groups of individuals achieve coordination and collective action is an important topic in the natural sciences, but until recently the role of leadership in this process has been largely overlooked. In contrast, leadership is arguably one of the most important themes in the social sciences, permeating all aspects of human social affairs: the election of Barack Obama, the war in Iraq, and the collapse of the banks are all high-profile events that draw our attention to the fundamental role of leadership and followership. Converging ideas and developments in both the natural and social sciences suggest that leadership and followership share common properties across humans and other animals, pointing to ancient roots and evolutionary origins. Here, we draw upon key insights from the animal and human literature to lay the foundation

Why do people purchase proenvironmental “green ” products? We argue that buying such products can be construed as altruistic, since green products often cost more and are of lower quality than their conventional counterparts, but green goods benefit the environment for everyone. Because biologists have observed that altruism might function as a “costly signal ” associated with status, we examined in 3 experiments how status motives influenced desire for green products. Activating status motives led people to choose green products over more luxurious nongreen products. Supporting the notion that altruism signals one’s willingness and ability to incur costs for others ’ benefit, status motives increased desire for green products when shopping in public (but not private) and when green products cost more (but not less) than nongreen products. Findings suggest that status competition can be used to promote proenvironmental behavior.

Why do people purchase pro-environmental “green ” products? We argue that buying such products can be construed as altruistic, since green products often cost more and are of lower quality than their conventional counterparts, but green goods benefit the environment for everyone. Because biologists have observed that altruism might function as a “costly signal” associated with status, we examined in three experiments how status motives influenced desire for green products. Activating status motives led people to choose green products over more luxurious non-green products. Supporting the notion that altruism signals one’s willingness and ability to incur costs for others ’ benefit, status motives increased desire for green products when shopping in public (but not private), and when green products cost more (but not less) than nongreen products. Findings suggest that status competition can promote pro-environmental behavior.

Costly third party punishment has been utilized as a tool for studying the enforcement of social norms. Experiments on this topic typically involve a third party observer who can pay to decrease the payoff of a