Trust and honesty are essential for human interactions. Philosophers since antiquity have long posited that they are causally linked. Evidence shows that honesty elicits trust from others, but little is known about the reverse: does trust lead to honesty? Here we experimentally investigated whether trusting young children to help can cause them to become more honest (total N = 328 across five studies; 168 boys; mean age, 5.94 years; s.d., 0.28 years). We observed kindergarten children’s cheating behaviour after they had been entrusted by an adult to help her with a task. Children who were trusted cheated less than children who were not trusted. Our study provides clear evidence for the causal effect of trust on honesty and contributes to understanding how social factors influence morality. This finding also points to the potential of using adult trust as an effective method to promote honesty in children.

信任和诚实对于人际交往至关重要。自古以来的哲学家早就认为它们之间存在因果关系。有证据表明，诚实会引起他人的信任，但相反的情况却鲜为人知：信任会带来诚实吗？在这里，我们通过实验调查了信任幼儿帮忙是否可以使他们变得更加诚实（五项研究中的总人数N  = 328；168 名男孩；平均年龄，5.94 岁；标准差，0.28 岁）。我们观察了幼儿园的孩子们在接受大人委托帮助完成一项任务后的作弊行为。被信任的孩子比不被信任的孩子作弊的情况要少。我们的研究为信任对诚实的因果影响提供了明确的证据，并有助于理解社会因素如何影响道德。这一发现还表明，利用成人信任作为促进儿童诚实的有效方法具有潜力。