Directives, expressives, and motivation
当代理人的动机受上级对其能力看法影响时，上级必须权衡信息与表达。研究发现，上级只有通过模糊指令才能可信地表达信任，而明确指令可能透露不信任并降低代理人努力水平。
When an agent's motivation is sensitive to how his supervisor thinks about the agent's competence, the supervisor has to take into account both informational and expressive contents of her message to the agent. This paper shows that the supervisor can credibly express her trust in the agent's ability only by being unclear about what to do. Suggesting what to do, i.e., 'directives,' could reveal the supervisor's 'distrust' and reduce the agent's equilibrium effort level even though it provides useful information about the decision environment. There is also an equilibrium in which directives are neutral in expressive content. However, it is shown that neologism proofness favors equilibria in which directives are double-edged swords.