This paper studies the vulnerability of the pivotal mechanism with respect to manipulation by groups. In a lab experiment, groups decide on the implementation of various alternatives, some of which imply opposite interests for the two subgroups. We investigate the occurrence of tacit and...

We study behavior within a simple principal-agent experiment. Our design allows for a large class of linear contracts. Principals can offer any feasible combination of (negative) fixed wages and incentives in the form of return sharing. This great contractual flexibility allows us to study...