Gambling fallacies are irrational beliefs about how gambling works. They are measured using questionnaires such as the Gambling Fallacies Measure (GFM). This study compared how people who gamble on poker professionally and people who do not gamble on poker professionally answered altered versions of item 5 of the GFM. Participants were randomly assigned to complete either (1) the original item 5 of the GFM (the control condition); (2) a modified version of the item focusing on positive attitude only; or (3) a modified version of the item focusing on good deeds only. People who gambled professionally had higher scores on the GFM than people who did not gamble professionally. Compared to those in the control condition, participants were more likely to disagree with the version stating, “doing good deeds increases your likelihood of winning money when gambling.” They were less likely to disagree with the version stating, “A positive attitude increases your likelihood of winning money when gambling”. Responses to the “good deeds” version were more strongly associated with responses to other GFM items among professional players. The “good deeds” version may be more useful to assess gambling fallacies among people who gamble on poker professionally.
