Tatsuya Kameda

Social influence in consensus formation was examined using a notion of sociocognitive network. Given the robustness of shared information in determining group decisions, the authors propose the concept of a sociocognitive network that captures the degree of members' knowledge-sharing prior to group interaction. A link connecting a given pair of members represents the amount of information that the pair shares before interaction. As in a regular social network, a member's status can be defined by

Research on group decision making has several distinctive roots in social sciences. Besides psychological and sociological interests about how people make decisions as a collective (e.g., Coleman, 1990; Witte & Davis, 1996), group decision making has also been a major research topic in the interdisciplinary area, called social choice theory, that intersects economics and political science (Arrow, 1963; Black, 1958; Fishburn, 1973; Ordeshook, 1986). Although these disciplines differ in many ways

This study addressed interpersonal factors affecting group entrapment and also attempted to delineate a conceptual link between collective entrapment and I. L. Janis's (1972, 1982) notion of groupthink. Two experiments were conducted in which 3-person groups were assigned either majority or unanimity rule as an official consensus requirement for their initial decision. It was expected and confirmed that groups whose initial decision processes were guided by unanimity rule were entrapped more oft

Although norms can potentially serve useful constructs to understand human minds, being fundamentally social in evolutionary as well as cultural senses, there are as yet no useful psychological theories of adaptive norm development. This article provides an illustrative model about how a norm emerges in a society. We focus on the "communal-sharing norm" in primordial societies, a norm designating uncertain resources as common properties to be shared with other members. Based on anthropological f

Distributive justice concerns the moral principles by which we seek to allocate resources fairly among diverse members of a society. Although the concept of fair allocation is one of the fundamental building blocks for societies, there is no clear consensus on how to achieve "socially just" allocations. Here, we examine neurocognitive commonalities of distributive judgments and risky decisions. We explore the hypothesis that people's allocation decisions for others are closely related to economi

The exploration-exploitation dilemma is a recurrent adaptive problem for humans as well as non-human animals. Given a fixed time/energy budget, every individual faces a fundamental trade-off between exploring for better resources and exploiting known resources to optimize overall performance under uncertainty. Colonies of eusocial insects are known to solve this dilemma successfully via evolved coordination mechanisms that function at the collective level. For humans and other non-eusocial speci

Tatsuya Kameda, Mark F. Stasson, James H. Davis, Craig D. Parks, Suzi K. Zimmerman, Social Dilemmas, Subgroups, and Motivation Loss in Task-Oriented Groups: In Search of an "Optimal" Team Size in Division of Work, Social Psychology Quarterly, Vol. 55, No. 1 (Mar., 1992), pp. 47-56

We introduce a game theory model of individual decisions to cooperate by contributing personal resources to group decisions versus by free riding on the contributions of other members. In contrast to most public-goods games that assume group returns are linear in individual contributions, the present model assumes decreasing marginal group production as a function of aggregate individual contributions. This diminishing marginal returns assumption is more realistic and generates starkly different

A number of studies have shown that individuals often spontaneously mimic the facial expressions of others, a tendency known as facial mimicry. This tendency has generally been considered a reflex-like "automatic" response, but several recent studies have shown that the degree of mimicry may be moderated by contextual information. However, the cognitive and motivational factors underlying the contextual moderation of facial mimicry require further empirical investigation. In this study, we prese