We report on an experiment using video technology to study effects of communication on donations to and discrimination between potential receivers. The experimental design eliminates strategic factors by allowing two receivers to unilaterally communicate with an anonymous dictator before the latter decides on her gifts. Through the use of three communication setups (none, audio, and audio-visual) we analyze purely social effects of communication. A silent video channel leads to discrimination between potential receivers based on impression formation, but does not affect average levels of donations. When the auditory channel is added, average donations increase. The social processes invoked by the visual and audio channels are heterogeneous and communicator-specific but not unsystematic.