Pathological gamblers tend to find patterns that aren't actually there and are more likely to act on impulse.

Researchers Wolfgang Gaissmaier and Andreas Wilke confirmed that gamblers tend to be prone to perceiving illusory patterns by comparing the betting habits of habitual gamblers against non-gamblers. Participants were shown a picture of two slot machines, one with a much higher probability of winning than the other—and were asked to predict whether a coin would come from the slot machine on the right or left. Rational thought would suggest to always bet on the slot machine with the better winning probability—but many gamblers feel they "know" in which trials they have to bet on which slot machine, which is of course, impossible.

Gaissmaier and Wilke also measured impulsivity amongst the participants. They administered cognitive reflection tasks where participants had to answer a question that had an answer that came quickly to mind but was incorrect, and a correct answer that was much less obvious. Habitual gamblers tended to get more of these types of questions wrong, indicating a tendency to "bet" impulsively.