Slot machines trick losers into thinking they're winning

Whatever casino you are in, slot machines sound more or less the same: jangly music, the whir of spinning reels, accompanied by loud beeps and chimes.

A recent study shows that some of those noises can easily fool our brains into thinking that we won - even when we have unequivocally lost money.

"The way slot machines are designed, sound is a really crucial component of player feedback," said behavioural neuroscientist Michael Dixon of the University of Waterloo in Ontario.

Because the jubilant sounds are always tied to wins or even partial losses - "losses disguised as wins", Dixon, the lead author, calls them - they act as positive reinforcement and can skew our perception of lost money.

Say you wager $1 for a single spin. If you hit a winning combination and win $5, you are rewarded with flashing animations and celebratory jingles made to give you a sense of accomplishment. When you win nothing, the machine goes into a state of rest with no lights or music. It just waits for you to play again.

The catch is, even when you win just a portion of your wager back - for instance, 25 cents out of the dollar you put in - the machine still gives you happy noises and such, similar to when you really win. So even though you have actually lost money, you come away feeling like a winner.