Is it costly to deceive? People are adept at detecting gossipers' lies but may not reward honesty.

The possibility that gossipers may share dishonest reputational information is a key challenge to claims that gossip can shore up cooperation in social groups. It has been suggested that imposing social costs on dishonest gossipers should increase the honesty of these reputational signals. However, at present, there is little evidence of people's willingness to impose costs on dishonest gossipers; there is also little evidence of their ability to detect gossipers' lies in the first place. This paper aims to shed light on people's abilities to detect dishonest gossip and their treatment of those who share it. To do this, we report the results of two trust game studies using the strategy method (study 1) and repeated interactions in the laboratory (study 2). We show that in an environment where gossipers tell spontaneous lies people are more inclined to believe honest than dishonest gossip. We also show that people are more likely to treat favourably gossipers they believe to be honest, but that this does not always result in more favourable treatment for gossipers who were actually honest. We discuss the implications for the potential utility of social sanctions as a tool for securing honesty. This article is part of the theme issue 'The language of cooperation: reputation and honest signalling'.