Problem gamblers tend to have a winning streak or big win early in their gambling careers.
They've been conditioned to believe it will pay out. People who win early on tend to get both positive reinforcement, from the thrill of winning and the financial pay-off, as well as negative reinforcement, as a temporary escape from emotional or other problems. The study of more than 150 people also found that, although problem gamblers had a slightly worse understanding of odds, in general most people did not have a sense of how randomness worked. Winning therefore reinforces any player's incorrect perceptions, and also feeds into dreams. The Centre study also found that problem gamblers were more likely than social or infrequent gamblers to find patterns in a series of lines, whether there was an actual pattern or the lines were randomly drawn and just interpreted as patterns.