When individuals learn from what others tell them, the information is subject to transmission error that does not arise in learning from direct experience. Yet evidence shows that humans consistently prefer this apparently more unreliable source of information. We examine the effect this preference has in cases where the information concerns a judgment on others’ behaviour and is used to establish cooperation in a society. We present a spatial model confirming that cooperation can be sustained by gossip containing a high degree of uncertainty. Accuracy alone does not predict the value of information in evolutionary terms; relevance, the impact of information on behavioural outcomes, must also be considered. We then show that once relevance is incorporated as a criterion, second-hand information can no longer be discounted on the basis of its poor fidelity alone. Finally we show that the relative importance of accuracy and relevance depends on factors of life history and demography.