A surprisingly large amount of lottery prizes are left unclaimed each year. This irony leads us to suspect that what we bet on is not money, but good mood. We present three studies that aim to explain why people play lottery games from an emotional perspective. In Study 1, a large-scale online survey was conducted to investigate lottery buyers’ mood changes of lottery playing. People are in their best mood before knowing whether they have won or not. In Study 2, we manipulated the way to reward (choosing lottery tickets vs. choosing cash) and compared participants’ mood changes at different stages of a rewards game in laboratory settings. First, participants in the lottery group were generally in a better mood. Second, 42% of participants from the lottery group did not show up in the laboratory to collect scratch cards. Third, participants in the lottery group took more time to return to the laboratory to check their tickets than participants in the cash group to resume their cash. In Study 3, we examined whether priming bad/good mood can improve people’s preference for lottery tickets/cash. People who were primed in a bad mood showed a high preference for lottery tickets.

A surprisingly large amount of lottery prizes are left unclaimed each year. This irony leads us to suspect that what we bet on is not money, but good mood. We present three studies that aim to explain why people play lottery games from an emotional perspective. In Study 1, a large-scale online survey was conducted to investigate lottery buyers’ mood changes of lottery playing. People are in their best mood before knowing whether they have won or not. In Study 2, we manipulated the way to reward (choosing lottery tickets vs. choosing cash) and compared participants’ mood changes at different stages of a rewards game in laboratory settings. First, participants in the lottery group were generally in a better mood. Second, 42% of participants from the lottery group did not show up in the laboratory to collect scratch cards. Third, participants in the lottery group took more time to return to the laboratory to check their tickets than participants in the cash group to resume their cash. In Study 3, we examined whether priming bad/good mood can improve people’s preference for lottery tickets/cash. People who were primed in a bad mood showed a high preference for lottery tickets.