Go to any casino in the world, and you’ll hear the familiar jingles, bells, and coin sounds coming from the endless rows of slot machines that cover all corners of the casino floor. According to new research from the University of Waterloo in Canada, these sounds are actually a key component to the game, helping to make the machines more exciting – and fool players into thinking they’re winning more than they are.

Sounds Affect Players’ Perceptions

The research, led by Dr. Michael Dixon, was started after his team realized that celebration noises were as old as slots themselves. But while early slots would simply ring a bell when a player won, modern slots average around 400 different sound effects each. They also noted that on modern multi-line slots, it’s quite possible for a player to actually lose money on a spin even if they win a small amount on a single line. In that situation, the player still gets the “winning” noises, despite the fact that they got less out of the machine than they put in.

The study recruited 96 gamblers to play two different sessions on a slot machine simulation. In one of the sessions, any winnings that came out of the machine were greeted by the celebratory noises, as normal. In the second session, there were no noises: only visual feedback was given to the players.

Players Prefer More Sounds

At the end of the study, the researchers found that the players had a strong preference for the version of the game that used noise to signal a win. This came across both in their own responses, as well as in subconscious responses such as skin conductance – in other words, how much their palms were sweating.

Perhaps more interesting was how the players rated their results. Players overestimated the number of times they had won on the machine regardless of which game they played. But the overestimation was much greater when playing the game with sound, rather than the one that only relayed visual information.

According to the research team, this may mean that sound is a factor in drawing players to slots – and could even be a factor in problem gambling.

“Although sounds may have contributed to players’ enjoyment of the game, sound may also lead to an overestimation of winning,” the researchers said. “Both of these effects may contribute to gambling problems, such as misbeliefs about the true chances of winning, and persistence that some players experience when playing slot machines.”