Order with Some Law: Complementarity versus Substitution of Formal and Informal Arrangements
通过实验检验正式合同与非正式安排的关系，发现合同能促进非合同维度的自我执行，尤其在重复交易可能性低时互补效应显著，未发现合同替代社会规范的证据。
While some argue that incomplete incentive contracts facilitate the self enforcement of informal dealings, other authors submit that they substitute for or ‘‘crowd out’’ social norms supporting informal arrangements. We use experimental evidence to test these theories by manipulating the extent to which individuals transact repeatedly and the level of contract costs. We find that, by enforcing contractible exchange dimensions, contracts facilitate the self-enforcement of noncontractible dimensions. This complementarity effect is particularly important when repetition is unlikely and thus self-enforcement is difficult. Although our data suggest the existence of reciprocity as an alternative, informal enforcement mechanism, we do not find evidence that contracts substitute for this social norm.