In this paper we argue that authorities aid cooperation by means ofdirect coordination or the enforcement of re-commitment devices suchas contract laws.Credible threats of violence allow this role. In alocal interaction model, an authority forms if mutually connected individuals with sufficient...

The advantages and disadvantages of genetic modification of organisms in agriculture are reviewed. These relate to the environment, human health, socio-economic effects, population growth, and differential consequences for developed and developing countries. An overall evaluation requires that...

We compare a partners condition where the same small group of subjects plays arepeated public good game to astrangers condition where subjects play this game in changing group formations.Subjects in the partners conditioncontribute from the first period on significantly more to the public good...