  We examine behavior in an experimental collaboration game that incorporates
endogenous network formation. The environment is modeled as a generalization of
the voluntary contributions mechanism. By varying the information structure in
a controlled laboratory experiment, we examine the underlying mechanisms of
reciprocity that generate emergent patterns in linking and contribution
decisions. Providing players more detailed information about the sharing
behavior of others drastically increases efficiency, and positively affects a
number of other key outcomes. To understand the driving causes of these changes
in behavior we develop and estimate a structural model for actions and small
network panels and identify how social preferences affect behavior. We find
that the treatment reduces altruism but stimulates reciprocity, helping players
coordinate to reach mutually beneficial outcomes. In a set of counterfactual
simulations, we show that increasing trust in the community would encourage
higher average contributions at the cost of mildly increased free-riding.
Increasing overall reciprocity greatly increases collaborative behavior when
there is limited information but can backfire in the treatment, suggesting that
negative reciprocity and punishment can reduce efficiency. The largest returns
would come from an intervention that drives players away from negative and
toward positive reciprocity.
