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# Ask the Slot Expert: Making bonuses more frequent on a slot machine

25 May 2016

Question: Quoting from "Strictly Slots," concerning the new Gong Xi Fa Cai IGT slot game, brings up an RNG question that I’ve never seen addressed. The quote is:

“The manufacturer says the side bet also causes the bonus features to occur more frequently.” (emphasis added.)

Now, if the RNG throws out random numbers, which I would assume correspond to the bonus symbols (or whatever type of bonus triggers there may be), how can the RNG reconfigure the numbers it’s constantly throwing out to make the game’s bonus features occur more frequently? Even if the bonus feature has nothing to do with the RNG, there has to be something in the machine that is being automatically changed to make for more frequent bonuses.

The RNG does generate a stream of numbers. The numbers themselves are just numbers. They don't in and of themselves correspond to anything. If the RNG generated 732,495, it means only that the RNG generated the number 732,495.

It's up to the program running the slot machine to do something useful with the numbers generated by the RNG. Our number 732,495 might correspond to a single bar on reel 1, a triple bar on reel 2 or a blank on reel 3. One useful thing the program can do with the output from the RNG is determine where each reel will stop.

If the bonus feature the quote is referring to was triggered by symbols on the reels, then it would be impossible to make bonus symbols appear more frequently when a player makes the side bet.

The bonus feature, however, is triggered randomly with each spin. It is not triggered by symbols on the screen.

The program gets five numbers for the RNG and uses each one to determine where the corresponding reel will stop. It can then get a sixth number from the RNG to determine if the bonus will be triggered on this spin.

There are many ways the program can use this sixth number to determine whether to trigger the bonus feature. The following is probably not how it's done.

The program could scale the number from the RNG to a value between 0 and 99, inclusive, using modulo arithmetic. It could then compare the scaled number against a trigger value. If the frequency of getting the bonus feature is 1 in 100 without the side bet, the program could check if the number equals 0 (or 50 or 99 or any individual number) and if it does, start the bonus feature.

If the bonus feature frequency jumps up to 5 out of 100 with the side bet, the program could check that the number is less than or equal to 4, or greater than or equal to 95, or any one of five individual numbers.

There is no change to the output from the RNG. That is illegal. What does change is what the program is doing with the output from the RNG to make the bonus feature more frequent when you make the side bet.

Question: My question sounds a little dumb. My wife and I go to Indian casinos. She wins all the time. And people around us win.

But me?

She says it's my mindset or way of thinking. I asked how a machine knows what you are thinking.

But it is strange that I never win, but everyone around me does. I play the same slots they play. This bugs me.

Answer: One of the dumbest things I ever heard someone say while playing the slots is, after hitting a small jackpot, "I had a feeling about this machine."

It's not that the statement is dumb in and of itself. What's dumb is what it implies. Would you ever sit down at a machine thinking that it will drain your wallet? If you felt that a machine was going to be cold, why would you play it? We always have the hope that we'll win some money from a machine.

There's nothing wrong with having a positive attitude while gambling but, I agree, the machine does not know what you're thinking. Your attitude won't affect your results. (I did flip through a slot book, however, in which the author credits her success at the slots with her positive attitude.)

The most common reason for your experience is selective memory. You're convinced that you lose and everyone around you wins, so the instances in which this happens stand out in your mind. They carry more weight in your memories because they reinforce your belief. The instances in which you win and others lose don't register in your memory because they go contrary to your belief.

Scientists deal with selective memory by taking comprehensive notes. A number of years ago, video poker players were convinced that when you held two pair, you would draw a card of the same rank to replace your discard more frequently than should happen with a fair deck. When mathematicians investigated and kept records, they discovered that the same-rank flaw was a result of selective memory. Drawing a card of the same rank did not occur more frequently than it should have. Nevertheless, every time I draw a card of the same rank, it stands out in my mind because I remember this controversy. The times when I get a different rank don't stand out because there's nothing special about them.

There's another possibility. Some people have extreme luck. Somebody has to be in the tails of the normal curve.

Frank Scoblete wrote about a couple who played Joker Poker in Atlantic City. Even though it's a negative expectation game, this couple consistently showed a profit playing the game. They were consistently very lucky.

You might be consistently unlucky.

The technical term for an incredibly unlucky person is schlimazel.

John Robison

John Robison is an expert on slot machines and how to play them. John is a slot and video poker columnist and has written for many of gaming’s leading publications. He holds a master's degree in computer science from the prestigious Stevens Institute of Technology.

You may hear John give his slot and video poker tips live on The Good Times Show, hosted by Rudi Schiffer and Mike Schiffer, which is broadcast from Memphis on KXIQ 1180AM Friday afternoon from from 2PM to 5PM Central Time. John is on the show from 4:30 to 5. You can listen to archives of the show on the web anytime.

#### Books by John Robison:

The Slot Expert's Guide to Playing Slots
John Robison
John Robison is an expert on slot machines and how to play them. John is a slot and video poker columnist and has written for many of gaming’s leading publications. He holds a master's degree in computer science from the prestigious Stevens Institute of Technology.

You may hear John give his slot and video poker tips live on The Good Times Show, hosted by Rudi Schiffer and Mike Schiffer, which is broadcast from Memphis on KXIQ 1180AM Friday afternoon from from 2PM to 5PM Central Time. John is on the show from 4:30 to 5. You can listen to archives of the show on the web anytime.

#### Books by John Robison:

The Slot Expert's Guide to Playing Slots