Ben-Ner, Avner and Louis Putterman. 2009. Trust, communication and contrast: An experiment. Journal of Economic Behavior & Organization 70(1-2):106-121.

In the one-shot trust or investment game without opportunities for reputation formation or
contracting, economic theory predicts no trusting because there is no incentive for trustworthiness.
Under these conditions, theory predicts (a) no effect of pre-play communication,
and (b) universal preference for moderate cost binding contracts over interacting without
contracts. We introduce the opportunities to engage in pre-play communication and to
enter binding or non-binding contracts, and find (a) communication increases trusting and
trustworthiness, (b) contracts are largely unnecessary for trusting and trustworthy behaviors
and are eschewed by many players, (c) more trusting leads to higher earnings, and
(d) both trustors and trustees favor “fair and efficient” proposals over the more unequal
proposals predicted by theory.