In a public goods experiment, subjects can vary over a period of stochastic length two contribution levels: one is publicly observable (their cheap talk stated intention), while the other is not seen by the others (their secret intention). When the period suddenly stops, participants are...

We report on an experiment using video technology to manipulate pre-play communication protocols in the lab and to study purely social effects of communication on donations and discrimination between potential receivers. The experimental design eliminates strategic factors by allowing two...