Gamblers ignore important information when placing a bet

Instead, people with gambling disorder pay more attention to irrelevant information from the previous gamble to inform their next choice.

"Our research may help explain why individuals with gambling disorder continue to gamble in the face of mounting losses, and on games that have a very small chance of winning," said Eve Limbrick-Oldfield, the study's lead author and a postdoctoral research fellow at the UBC department of psychology and Centre for Gambling Research.

To conduct the study, the researchers recruited two groups of participants, 48 of whom have gambling disorder and 35 control participants. The participants were asked to complete a computerized decision-making task where they repeatedly chose between two lotteries. The two lotteries varied in prize size and chance of winning -- one lottery had a smaller prize, but higher chance of winning while the other had a larger prize, but a smaller chance of winning. The participants were given all the information that was needed to make an optimal decision.

"We found control participants paid attention to both the prize size and chance of winning when choosing between the lotteries but the individuals with gambling disorder were more likely to ignore that information. Instead, they relied on whether they won or lost in the last gamble to make a decision," said Limbrick-Oldfield. "The finding can be easily translated into real-world gambling situations. For example, someone using a slot machine that hasn't paid out in a while can believe that the machine is somehow 'due' a win."

This study is the first of its kind to see whether win size and probability information have an effect on how individuals with gambling disorder make decisions. The findings support the hypothesis that individuals with gambling disorder are susceptible to irrelevant sources of information to guide gambling decisions.

The researchers do not know whether this impaired decision-making predates the gambling disorder or is a consequence of prolonged gambling but they hope to find out in future research. They are currently working on another study that uses eye-tracking to see if problem gamblers pay more attention to certain information given to them.

"These findings could help inform psychological treatments for gambling disorder that work on dismantling erroneous beliefs and enhancing financial literacy," said Luke Clark, UBC Centre for Gambling Research director and a professor in the department of psychology.

The research team also hope the findings could be used when building algorithms for online gambling websites to identify those gamblers who might be at risk of having a gambling problem.