In this study, the researchers simply intercepted people who were standing in line to place two-dollar bets and other people who had just left the window. The investigators asked them how certain they were that their horses would win. The bettors who had placed their bets were far more certain about their choice than the folks waiting in line.19 Yet nothing had changed except the finality of placing the bet. People become more certain they are right about something they just did if they can’t undo it.
