Biased information about the payoffs received by others can drive innovation, risk taking, and investment booms. We study this cul- tural phenomenon using a model based on two premises. The first is a tendency for large successes, and the actions that lead to them, to be more salient to onlookers than small successes or failures. The second premise is selection neglect—the failure of observers to adjust for biased observation. In our model, each firm in sequence chooses to adopt or to reject a project that has two possible payoffs, one positive and one negative. The proba- bility of success is higher in the high state of the world than in the low state. Each firm observes the payoffs received by past adopters before making its decision, but there is a chance that an adopter’s outcome will be censored, especially if the payoff was negative. Failure to account for biased censorship causes firms to become overly optimistic, leading to irrational booms in adoption. Booms may eventually collapse, or may last forever. We describe these effects as a form of cultural evolution, with adoption or rejection viewed as traits transmitted between firms. Evolution here is driven not only by differential copying of suc- cessful traits, but also by cognitive reasoning about which traits are more likely to succeed—quantified using the Price Equation to decompose the effects of mutation pressure and evolutionary selection. This account provides an explanation for investment booms, merger and initial public offering waves, and waves of technological innovation.