How does the process of information transmission affect thecultural products that emerge from that process? This questionis often studied experimentally and computationally via iter-ated learning, in which participants learn from previous partic-ipants in a chain. Much research in this area builds on math-ematical analyses suggesting that iterated learning chains con-verge to people’s priors. We present three simulation studiessuggesting that when the population of learners is heteroge-neous, the behavior of the chain is systematically distorted bythe learners with the most extreme biases. We discuss implica-tions for the use of iterated learning as a methodological tooland for the processes that might have shaped cultural productsin the real world.