Slot Machines: Expectations vs. Reality

Row of Slot Machine Games in Casino
Slot machine games are great profit centers for online and land-based casinos. Even though most players know the games favor the house, they continue to deposit their money.

There is a social aspect to playing real money slot machine games in a casino. You can chat with your neighbors, whether they’re friends or strangers. The casino is relaxing and exciting at the same time.

Researchers in the fields of gaming science and psychology began publishing studies in the late 1980s and early 1990s that peeled back some of the secrets of the slot gaming industry.

They were playing up our expectations to keep us playing their games. While that shouldn’t come as a surprise to anyone today, the public was more naive back then. We didn’t have the internet to help us expose industry secrets.

If you were lucky, you found an honest book about gambling in bookstores. Most people probably got their Vegas inside secrets from newspaper insert magazines and little booklets bought in grocery stores.

Where is the dividing line between what real money slot gamers expect and what they receive? Here are a few things that come to mind.

Everyone Expects to Win

Deep down inside you really do expect to win at some point no matter how much you tell yourself that you’re just playing for fun.

After all, the games pay prizes. Some slot machine prizes are just less expensive losses.

Slot machine games are designed to reinforce the expectation of winning. Several research studies, like this one by “Journal of Gambling Studies”, have found that games create and reinforce this expectation.

That study evaluated how multi-line video slot games use “LDWs” (losses disguises as wins) to lure players into playing longer. Say you’re playing a 50-line slot machine game and it charges a penny per pay line. It may pay a prize of 30 cents on a basic bet.

That’s a loss but it looks like a “win.” The game may even say, “you win 30 cents!”

Games Come Close to Paying Off

This is another old tactic. The Nevada Gaming Commission held a series of hearings in which game-makers and casino operators admitted to using “clustering” to simulate “near wins.”

On older slot machine games, the reels (controlled by computer chips) would align two out of three winning symbols but the third reel stopped on a blank slot. Some real money games were designed to pause on the winning symbol then roll up or down to a blank slot.

Up Close Slot Machine Keys

This deceptive trick was called out by gambling addiction advocates and other groups. It’s fallen out of practice and in some jurisdictions, it’s forbidden.

Your expectation that a game comes close to paying off isn’t that far-fetched. If all you need to win a jackpot is a single random number like 998 and the random number generator produces 997 for the next spin, that is mathematically close.

But this expectation is easily exploited into creating a false hope. The bottom line is always the same. You either win back your bet or more, or you lose money.

Playing Longer Improves Your Chances of Winning

This is a controversial expectation. On the one hand, if you’re a budget player who isn’t concerned about winning, then it makes sense to use a conservative strategy.

That means making only minimum bets and extending your play time as long as possible. I met one player who compared it to putting more quarters into an arcade video game so he could keep shooting. He was just a terrible shot with the arcade’s gun.

At least, with a slot machine game, you might win a jackpot. In an arcade video game, you get to list your initials on the Top 10 Players page until someone knocks you off.

In 2008, Kyle Siegrist of the University of Alabama in Huntsville published a groundbreaking paper titled “How to Gamble If You Must.” His research used an imaginary even-money game called “Red and Black.” This is not a realistic scenario because no casino would offer such a game.

Siegrist’s finding that the longer a timid bettor (playing on minimum bets) plays, the greater the probability the house wins has often been cited.

Siegrist’s model says you have a better chance of reaching a target goal through bold play (betting the maximum) than through betting the minimum.

This finding assumes the house has an unlimited supply of money, and the player does not. In other words, he who has the most money wins. It just takes longer for the timid player to lose everything.

Your chances of reaching your target goal are better with bold bets because of the wild swings in random results. All you have to do is reach the goal once and you’re done. That’s more likely to happen with a big win than with a small win.

In reality, slot machine games are designed to pay less often than Siegrist’s “Red and Black” model. You still have a better chance of reaching a target goal with maximum bets but the odds are stacked against you.

And it’s not just because the theoretical return to player is less than 100%. It’s also because the house has more money than you.

Every Slot Game Is “Due” to Pay Off

I heard a story that a New Mexico casino was closed by the Indian tribe that owned it in the late 1990s because it went an entire day without paying a single slot game jackpot. I’ve tried without success to find a source for that story other than the person who told it to me.

If true, it would be an unusual event in the history of real money gambling. What the story tells me is that everyone expects slot games to pay sooner or later. By “pay,” I mean pay a big jackpot.

You can explain to someone how slot machine games work in fine detail, down to random number generators and virtual reels. They’ll understand you. But something happens when we start playing slot machine games.

We develop unrealistic expectations while playing the games.

Four Reel Casino Slot Machine, Money

In 1992, Michael Walker of the University if Sydney published a paper titled “Irrational thinking among slot machine players” in the Journal of Gambling Studies.

The study involved 27 university students who recorded their thoughts while playing slot machine games. The study found that slot game players are 38% more likely to engage in irrational thinking during gameplay than real money video poker and arcade game players.

The study participants were 80% more likely to make irrational statements about strategy while playing slot games.

When slot players say, “this game is due to pay off,” they’re not thinking rationally. They may acknowledge how random the results are before they sit down but as time goes by, their thinking becomes less rational.

In reality, every new spin has the same chance of triggering a jackpot as the last. That never changes.

You Win More With Higher Bonus Multipliers

If a slot bonus game is designed fairly, then when you’re asked to choose more free spins or higher multipliers, the math should work out about the same.

That doesn’t guarantee you’ll win the same amount of money on each bonus game. It does promise an equal chance.

There is no law I’ve heard about that requires all these bonus options to play by the same rules. Part of the mystery could be finding the combination that pays best.

Some slot machine games are designed to increase the bonus payoffs as you play through multiple bonus games. But when presented with a single screen and three or four choices of bonus round options, the player’s expectation should be that each set of options pays about the same.

That’s only fair. In reality, I’ve found myself preferring higher multipliers for wins on some slot games and more free spins on others. When I’m not playing the games, I realize these are irrational preferences. But I’d rather be paid 3x a prize than 2x a prize.

You have a better chance of winning big prizes with more free spins. Or do you?


I really do prefer blackjack to playing slot games. It’s more predictable and rational to me. The more I learn about how slot machine games are designed, the less I want to play them.

But I still play them when I’m in a casino and bored with the cards. Knowing that my thinking is biased toward unreasonable expectations doesn’t change my mind. I guess they got me there.

But that’s why I stick to a gambling budget. When I run out of slot game money, I go home.