Book Review Trusting What You Are Told by Paul Harris 2012, Harvard University Press, Cambridge, MA Review by Felix Warneken for The Quarterly Review of Biology Felix Warneken Harvard University warneken@wjh.harvard.edu December 2013 Cultural learning has been identified as a fundamental capacity to explain what makes us human. It allows humans to acquire knowledge and skills from others, rather than individuals having to reinvent the wheel on their own. Much discussion has ensued about the extent to which these capacities are human-unique, enabling cultural transmission at a rate and efficiency not found in even our closest evolutionary relatives. Paul Harris adds a new spin to this debate by pointing to a feature that had been neglected in these deliberations: children ask questions, lots of questions. Harris shows how children take an active role in the process of cultural transmission by seeking answers from others and evaluating what is presented to them. From a surprisingly early age, children weigh new pieces of information against their own experience and the multiple (and often conflicting) answers that different adults provide. For example, four-year-old children can track a person’s past accuracy and are thus not lost when two people call a new entity by different names – they will go with who had been proven to be a reliable informant and ignore the person who mislabeled known entities in the past. Moreover, even if an informant appears to be completely certain about something, they ignore that information if a group majority disapproves the individual’s claim. The minds of children as formulated by Harris’ work are curious, but also inquisitive and critical, allowing them to sift through the abundance of information that culture provides them. While developing his argument, Harris reviews a large body of empirical work, extending from developmental psychological experiments over cross-cultural and ethnographic studies to comparative experiments with apes. The descriptions of these studies are quite detailed and thoughtful, so that readers can gain a deep understanding of the evidence without necessarily having to consult the original literature. Aware of the fact that the readers’ inquisitive minds will not uncritically believe every claim, Harris preemptively populates the discursive space with counterarguments and concerns, addressing them carefully throughout the book. In doing so, this book is a wonderful example of how to build an argument by integrating many voices. This book is a treat for everyone interested in cultural evolution and the ontogeny of the human mind – you can trust me on that.