Nullius in Verba—take nobody’s word for it—is the Royal Society’s great motto. Proof, not prestige, should be the true persuader. So when a group of academic research psychologists decided to take it seriously, the entire discipline was shaken by the results. The Reproducibility Project found it could substantively replicate the results of fewer than 40% of 100 high-profile experiments published in peer-reviewed journals. One study that failed replication claimed that encouraging people to believe there was no such thing as free will made them cheat more. Another study that failed the test reported on the effect of physical distance on emotional closeness. Volunteers asked to plot two points that were far apart on graph paper later reported weaker emotional attachment to family members, compared with subjects who had graphed points close together.