["Bulletin of Economic Research, EarlyView. ", "\nABSTRACT\nWe examine the role of prime numbers in conscious selection, the mental process by which players select numbers non‐randomly on a lotto ticket. Using three estimators of the popularity of numbers, we show that the tendency to overselect prime numbers significantly reduces individual gains. We use 10 years of public data from the Belgian National Lottery to demonstrate our main result and to test the robustness of our findings against several confounding factors such as the tendency to play birthday dates and the preference for “lucky” numbers. Evidence from two independent survey data sets corroborates our main finding."]