# Do Electronic Slot Machines Pick Symbols or Winners?

Does an electric slot machine have a table which determines the odds of getting particular combinations or does it determine if somebody wins and then picks a combination that produces the result?

Example of the first. Suppose two cherries in any of two (of three) columns is a \$1 win. And we want the player to have a 1% chance of getting this result.

Cherry / Cherry / Anything - Odds 0.33%
Cherry / Anything / Cherry - Odds 0.33%
Anything / Cherry / Cherry - Odds 0.33%

Then it picks “anything” at random (excluding cherry) for the last spot.

I suppose this could be a fully enumerated table as well. Assuming the other available symbols are Bell, Seven and Lemon:

Cherry / Cherry / Bell - Odds 0.11%
Cherry / Bell / Cherry - Odds 0.11%
Bell / Cherry / Cherry - Odds 0.11%
Cherry / Cherry / Seven - Odds 0.11%
Cherry / Seven / Cherry - Odds 0.11%
Seven / Cherry / Cherry - Odds 0.11%
Cherry / Cherry / Lemon - Odds 0.11%
Cherry / Lemon / Cherry - Odds 0.11%
Lemon / Cherry / Cherry - Odds 0.11%

Example of the second.

\$1 Payout - Odds 1% -> Produces a proper result.

No, I’m not planning a trip to a casino, just one of those random thoughts that pops into my head.

I’m not a slot machine programmer, but as a programmer and from things that I have read, I’m pretty sure that the answer is:

The machine plays the game the way a mechanical machine would. It assumes that it has three lists of symbols, it randomly selects an index into each list, and then looks up the value of the combination in a table of prizes.

The casino might change the table of prizes, but they wouldn’t change the odds of any particular combination coming up. Either way it works out to the same end result, but the original goal was to simulate the mechanism of the original game and so the code for the machines is going to have originally been written with that intent and for any developer after that, it would have been easier to pick three random things from three lists than to pick a random prize at the appropriate probability and then reverse engineer that back into a random answer of a type which would have given such a prize. It can be done, but it’s a hassle to do that versus just accepting the mechanics of the original game.

Interesting. I am not by any means a slot machine expert but my limited observation of them is that they like to tease the player. For example, if 777 is the jackpot, if you get 77 the last 7 will be just off. Oh so close, you should play again (sucker)! I would assume that if they are using a simulation of the wheels this wouldn’t happen so much. Again, I don’t know, and you could be correct.

I have no cite, but from what I have read, as soon as you push the bottom, a RNG, determines if you have won, and what amount, then the “wheels” stop based on that. And yes, it is programmed to give teasers, to make it look as if a payout, or larger payout was close to occurring.

So the wheels do not determine if you have won, … what you have won, determines where the wheels will stop.

That would seem both very complicated and very prone to hacking. Plus, modern machines let you pick multiple lines, so there are more possible amounts to win and lots more combinations. Simulating a mechanical machine like Sage Rat says would be a lot safer and easier.
As for the tease, all you would have to do is to increase the probability of a “7” on the first two lines and decrease it on the third. Plus, you will remember teasing situations more often than random ones, so you will naturally impute a higher probability to them than is actually the case.

It seems to be pretty widely accepted that slots are often programmed with ‘teasers’ to make it appear that you missed a big combination by just a little bit to encourage you to keep trying. That might not affect the overall odds of winning, but just creates a visual that makes the player feel as though they had almost won. So a RNG determines no jackpot was hit, but a teaser code then flips two 7’s on the line with the third just missing.

That’s just one of many cites a quick search on the subject returns.

Obviously the original, purely mechanical machines functioned as independent random elements, like dice. And when the wheels lined-up they caused payout via mechanical systems. Over the years they slowly became more and more electro-mechanical. Long ago the ‘arm’ mechanism became simply an electronic switch that triggered the action to start.

I imagine most if not all modern slot machines are now purely electronic. IOW they have no mechanical parts at all. The last mechanical remnant, the rotating display ‘wheels’, have finally been replaced with video screens. If that’s the case, well, then I’d imagine the OP is correct. As long as the math/odds for winning are still as stated then programming in teaser, fake, almost-winning, ‘near-miss’ displays wouldn’t be illegal. Or even unethical IMO. Gambling and gamblers are, well, stupid.

It would be pretty easy to have a number of pre-set animations. Just swap in the real answer at the end.

Though, even before the invention of the digital display, casino owners could have figured out that teases work and set up the reels to be heavy on 7s on the first two drums, with only one on the last. I don’t know if this is the case, but it would be alternate explanation for the phenomenon.

Surely taking advantage of the stupidity of others is, well, unethical?

I once asked this question about electronic slot bonus rounds that have you pick symbolic until you match or whatever. The answer there was it picks winners, but that struck me as a little over complicated, so maybe whatever the answer for the “main” game is true for the bonus.

In matters of gaming regulation, the answer is always “It’s completely fair and upfront. No trickery is present.” The psychology of gaming does not require trickery and teasing to keep people pumping in tokens and getting those dopamine hits.

More directly, it is against gaming regulations throughout the US to display results that are not what they seem. For instance, you aren’t allowed to show a near-miss more often than would happen naturally.

As for implementation: I see nothing in the Nevada regulations that would prevent a machine from drawing a conclusion first and then forming a fairly drawn random visual representation that gives that conclusion, but it would be bonkers to code it up that way, and probably impractical to demonstrate adherence to regulations. All the modern electronic machines that have a rich set of player choices are programmed the way you’d expect (i.e., actually simulating the game).

Of course, if there are 4 elements on the wheel - cherry, bell, 7, lemon - then the odds of 7,7,not 7 are 3 times more likely than 7 7 7. So of course it will look like you’re being teased.

The simplest way to program things would be a simulation - a separate RNG for each wheel, then evaluate the win potential of the results.

You can simulate the wheels AND hardcode near misses though, it’s not really that hard:

``````

fairly roll wheels (A,B,C), and near-miss value p in [0,1]

if (A,B,C) is a win or p > epsilon, display wheels
else (i.e. a loss where p <= epsilon), display a near-miss animation

``````

Well, that would mean banning all gambling entirely (and a lot more other things!)

Such ‘teasers’ were common on the old mechanical machines also.

The wheels in the columns aren’t just one repetition of each symbol – they occured more than once on the wheel. And the wheels for the first 2 columns could have “7” occurring more often, thus increasing the odds that the player would see “7 7 <something else>” and be fooled into thinking they ‘almost won the jackpot’, and so would play more*. (Just like games like in the McDonalds Monopoly promotion, there were many, many copies of most of the properties; but those that were needed to win the really big prizes were very rare.)

*What can be done on the current electronic machines is to program it so that the <something else> in the last column shows the winning “7” just above or below the line. That doesn’t change the odds of the game at all – it was still not a winning combination – but it can change the feeling of the player as to how close they were to winning.

I once was a programmer for a corporation that designs and builds electronic slot machines for various American Indian tribal casinos. When I started at the company, they were transitioning from mechanical reels to CGI wheels; patrons were pressing on the “glass” covering the reels, causing the glass to touch and slow the reels. This caused the display to show that a win had been attained, but there was no payout, because the reels did not end up in the configuration that had bee decided as soon as the player hit the “Spin” button.

As mentioned upthread, as soon as you press the button, the machine has already decided whether or not you have won, and, if so, what prize. Once that has been determined, all that is left is to “spin” the reels (or CGI reels), forcing them to stop at predetermined orientations. This gives the player the impression that the random conduct of the reels determines their prize, when nothing could be further from the truth.