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Slot machines inside New York New York hotel
Slot machines inside New York New York hotel
Ian Lloyd/Flickr

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Slot-machine science

How casinos get you to spend more money

The next time you find yourself in a casino, pause for a second to appreciate the architecture.

Casinos put an enormous amount of thought into their designs. The layout of the tables, the patterns on the carpet, the lighting — they're all explicitly engineered to make gambling more seductive and get you to spend more money.

One surprising example are the curving hallways around the property. Many casinos try to avoid making you ever have to turn at a 90° angle. As Natasha Dow Schüll explains in her fascinating book, Addiction By Design: Machine Gambling in Las Vegas, a right-angle turn forces people to call upon the decision-making parts of their brain — to stop and reflect on what they're doing. "Casinos don't want that," Schüll told me. "They want to curve you gently to where they want you to go."

But as Schüll discovered, almost nothing in a modern-day casino is more carefully engineered than its slot machines.

Slot machines and video gambling were once marginal to the success of casinos — but nowadays, they account for up to 85 percent of the gaming industry's profits. And casinos have devised a dizzying array of strategies to make these machines as addictive as possible, from the elaborate algorithms beneath the hood to the position of the armrests.

Schüll, a cultural anthropologist at MIT, spent 15 years in Las Vegas tracking the evolution of slot machines, exploring how and why they've become so addictive. We spoke by phone about how gambling has changed dramatically over time and how the gaming industry has drawn on psychological insights to make its games more addictive — often with tragic consequences.

Slot machines have become way more lucrative than traditional gambling


Slot Machines on board the Royal Caribbean cruise ship MS Independence of the Seas (Raging Wire/Flickr)

When people think of casinos, they often think of games like blackjack or roulette — high-stakes bouts of chance where fortunes can be won or lost in seconds. But that image is increasingly obsolete.

"Slot machines have this reputation for being these arcade devices only played by little old ladies," Schüll says. "But these devices are now driving the gambling industry and bringing in the majority of profits." By the late 1990s, slots were twice as profitable as all the other table games combined. She quotes one gambling official estimating that the machines account for as much as 85 percent of industry profits.

How did slots become so widespread? During the recession in the early 1990s, state legislatures started looking to increase revenue without raising taxes — and many of them settled on bills to allow machine gaming. "It was much easier to push through legislation [expanding the availability of slot machines] than things that carried a weightier vice image, like table gambling or poker," Schüll says.

The most recent recession saw another big bump. Maryland approved its first casino in 2008. Illinois began approving slot machines in bars in 2011. This past February, Massachusetts just approved its first slot parlor — at a racetrack outside of Boston. All told, there are now 39 states that legalize some form of electronic gambling in casinos, racetracks, or even bars and restaurants.

But the really crucial advance was technological. In the old days, slot machines were all-or-nothing affairs: you yanked the lever and either all the cherries or the lucky 7s lined up and you won some money — or you got nothing. That sort of game was only mildly profitable, and had limited appeal to players.

By the 2000s, better computer technology changed that. "The computerization of slot machines gave casinos such precise control over odds that they could offer much higher jackpots and more exciting games while really controlling percentage payback and the odds," Schüll says. And that's when slot machines really took off.

Today's slot machines are designed to hold your attention for as long as possible

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The gambling industry has realized that the biggest profits come from getting people to sit at slot machines and play for hours and hours on end. (Schüll says the industry refers to this as the "Costco model" of gambling.) As such, slot machines are designed to maximize "time on device."

Computerized slots have made this all possible. Again, in the old days, you pulled the lever and either won or you lost — and when people lost, they'd walk away.

Today's multi-line slot machines are far more elaborate. Instead of a single line, a player can bet on up to 200 lines at a time on the video screen — up, down, sideways, diagonal — each with a chance of winning. So a person might bet 70 cents and win on 35 of the lines, getting 35 cents back. That feels like a partial win — and captivates your attention.

"The laboratory research on this shows that people experience this in their brains in an identical way as a win," Schüll says. (And the economics research shows that these multi-line machines are far better at separating players from their money.)

That subtle advance, Schüll says, has helped revolutionize the gambling industry. Fewer and fewer people are now going to casinos to experience the thrilling chance at a big jackpot.

Instead, for many of the people Schüll interviewed, these slot machines have become a "gradual drip feed." They play because they enjoy being in the zone and losing themselves in the machine. Some players she talked to confessed that they actually get annoyed when they won a jackpot — because it disrupted the flow of playing.

The architecture of casinos helps convince people to keep gambling

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But it's not just the machine algorithms themselves. Casinos have a vast array of strategies to keep people gambling.

Modern machines now have ergonomic seats that don't cut off circulation and allow you sit for hours. Buttons and bill acceptors are placed so that they can be reached with minimal arm movement (and minimal disruption to play). Casinos have discovered that the most devoted players prefer machines to be sheltered in alcoves or crannies. "The entire architecture," Schüll says, is about ensconcing you in this comfy nook that allows you to have your own private escape."

Advances in payment systems have also been crucial — players no longer have to feed coins into the machine. Bill acceptors or player cards with magnetic strips allow people to play for longer and not think about the money they're spending. Many casinos have specialized ATMs with features that allow players to get around their daily withdrawal limits by advancing money.

There are also more subtle ways to keep people at machines. If casino officials notice that a player is on a bad streak, they can come over and offer the person free breakfast (This strategy can backfire, however, since it often irritates slot players trying to lose themselves in the flow of the game.)

Alternatively, Schüll discovered, video machines in the future may actually make internal adjustments if they notice that a player is on a losing streak and is reaching their "pain point." This has to be done carefully — it's illegal for casinos to change the odds in a game once a player has started playing. But, she says, some game manufacturers have exploring ways to reduce the volatility of a game in a way that still preserves the overall payback percentage. That's technically still legal.

There's a fierce debate about who's responsible for gambling addiction



It's hard to talk about gambling without talking about addiction, and Schüll devotes a large section of her book on the topic.

There's the woman who shows up at 3 am to play slots with her four kids in tow. There's a newcomer who sits down at a slot machine in a supermarket on Tuesday and doesn't leave until Thursday — maxing out three credit cards all the while.

(Those examples aren't random: Schüll finds that the stereotypical gambler in Las Vegas is no longer an older man betting on cards or the horsetrack but a 35-year-old mother of two hooked on slots.)

The gaming industry argues that it's only about 1 percent of the population that has a severe addiction problem. Most people, meanwhile, can play without consequence. Indeed, the American Gaming Association argues that the incidence of "problem" gambling hasn't really risen at all since 1976 — and that the amount wagered per casino visit hasn't increased significantly.* So, they argue, these machines don't appear to be fueling a massive increase in addiction.

But Schüll thinks the situation is more complicated than that. She cites studies by Brown University psychiatrist Robert Breen, who finds that video gambling machines are three to four times more addictive than games of old. "Of course some people are more predisposed to these kinds of problems by virtue of biography or brain chemistry," Schüll tells me. "But by the same token, certain technologies are more liable to addict. And I think its important to look at the technology."

"These games are solitary, they're really fast, they're continuous and uninterrupted," she says. "You're playing up to 1,200 spins an hour. And every event is another opportunity to reinforce behavior." So it's hardly a surprise that people quickly become addicted — losing themselves in the machines for days on end.

Schüll isn't convinced by industry arguments that responsibility for problem gambling belongs solely on individuals. "The whole modus operandi of the industry is to approach the human being as something that's manipulable. So I find it disingenuous that they then turn around and argue that 100 percent of the responsibility for any harm is on the person."

Some states and countries are mulling stricter regulations for machine gambling



In her book, Schüll argues that it's worth considering stricter regulations on video gambling — not a ban, but perhaps exploring ways to mitigate the worst addictive effects. "There's no equivalent of the FDA for these machines," she told me.

Still, regulating these machines is easier said than done. Countries like Canada or Australia have experimented with tweaks, like requiring pop-up messages that alert the player if they've been playing for too long. But researchers have found that other proposed interventions — like slowing down the reels — may actually backfire by lengthening the amount of time people play.

In the United States, meanwhile, Schüll argues that regulations remain lenient. States that are trying to expand video gambling as a source of revenue have been reluctant to throttle the nascent industry. That's particularly true now that casinos sales are falling and many states aren't getting the revenue they hoped.

Schüll does point to Massachusetts, however, as an example of "forward-looking" regulation, with policies that give frequent gamblers incentives to join "pre-commitment" programs — where they can limit in advance how much money they want to spend, before they start playing.

(By the way, for the opposing view, here's the American Gaming Association's view of the regulatory state of play — they argue that there are already plenty of rules and standards to prevent deception in these machines.)

But for the most part, the conversation around the addictive aspects of these machines is still fairly nascent. "I see my work as trying to open the door to discussion of this technology," she says, "and to figure out whether some sort of accountability and regulation of it might be appropriate."


* Update: Added a link to this AGA white paper on addiction numbers.

Brad Plumer:When people think of Las Vegas, they often think of blackjack or roulette or poker. But you basically argue that slot machines have become the dominant form of gambling — accounting for 85 percent of industry profits. How did this happen?

Natasha Dow Schüll:: Slot machines have this reputation for being these arcade devices only played by little old ladies. But these devices are now driving the gambling industry and bringing in the majority of profits

One of the reasons these machines rose to popularity had to do with the recession in the 1990s. States were looking at ways to raise revenue without raising taxes. And expanding the use of these devices was one way to do that. It was much easier to push through legislation there than for things that carried a weightier vice image, like table gambling or poker. And you could also classify these devices as lottery terminals — a way of legally classifying them under the lottery.

Plus, of course in the 1980s and the 1990s there was also this cultural shift, a comfort with technology. People were no longer freaking out at the thought of sitting and interacting with machines. They were becoming part of our daily routine, whether through ATMs or word processing.

But the changes I detail most extensively are the technological advances that allowed the casino industry to move beyond the three-reel mechanical devices of old — "the one-armed bandits." The computerization of slot machines gave the industry such precise control over odds that they could offer much higher jackpots and more exciting games.

Brad Plumer:What was fascinating was how much thought the gaming industry puts into the architecture of the casinos and the machines themselves — so much of it is cleverly designed to facilitate gambling.

Natasha Dow Schüll:: At every step of the way, casinos pay careful attention to how to get you to the machine, then how to get you to stay longer at it, then how to play more, and then get you coming back when the session's over.

There's this term that gets thrown out so often — "time on device." And you can see the focus on this everywhere.

There didn't even used to be seats at machines. Now there are these ergonomic seats that are carefully crafted not to cut off circulation, so you can sit there longer. There are studies showing that if sound gets bounced against walls and seems like it's coming somewhere else, players get tired more easily. So they avoid that. Same with the lighting or the sounds of the machine - everything is calibrated to create a smoother ride. The entire architecture is about ensconcing you in this comfy nook that allows you to have your own private escape.

Brad Plumer: Now you mentioned that these machines have changed — become more computerized. How has that made these machines more addictive?

Natasha Dow Schüll:: If you imagine the old three-reel mechanical slots, you would put in a coin and you would either lose the coin or you would double or triple your funds. So those machines were quite volatile.

But with the game algorithms today, you can make that experience smoother. In some of the newer video slots, you get a grid with many different symbols, rather than just three across. And now you can bet on up to 100 lines — say, a penny a line. So for the first time these slot machines aren't double or nothing. Instead you get a portion back. Put in 45 coins, get 25 back. And that means ever time you're getting some reinforcing stimuli.

Over time, you're losing money. But even when you lose, you're still getting a song, a jingle, the machine lights up and shows which lines you won on. It's pretty indistinguishable from the times you actually do win. And what the laboratory research on this shows is that people experience this in their brains as a win.

One of the arguments in my book is that the whole culture is turning to this time-on-device model of gambling. It's not so much about volatility and risk and chance. It's about the numbing comfortable experience that you're going to get — it's referred to as a smoother ride. And none of that would be possible with the old three reel, non-computerized machines.

Brad Plumer:One thing that struck me in your book is that most people aren't playing in the hopes of winning a big jackpot or playing for the thrill of it. They're essentially playing to escape — to lose themselves in the machines.

Natasha Dow Schüll:: For many people it's not about winning at all. I heard repeated stories of people who would actually get angry or frustrated or irritated when they won, because it would freeze up the machine. To me, that throws into relief that it's not about winning — it's more about the zone and time on device.

This is not gambling as we often understand it, it's not about excitement and thrill. It's about relaxing back with this glaze on your face. One of the algorithm designers for these games told me that they want people to "recline" on the mathematical model.

Brad Plumer: So let's talk about the business model here. In the old days, casinos were interested in the high rollers who flew into Las Vegas for a weekend and blew all their money. But now it seems like they're looking at repeat customers who will play video slots for as long as possible.

Natasha Dow Schüll:: This is what some have termed the "CostCo model," where casinos make their profits from volume. You're not just fleecing the big whale and getting him out. Money is made from low-rollers who are playing much, much more.

So you don't want to tap your consumers out. It's more about how to get customers to come back, or looking at the value of a customer over their whole lifetime. One place you see this is in Las Vegas and the Midwest is in a shift toward locals. There's this massive residential gambling community with their own casinos, designed in slightly different ways, and catering to this time-on-device model. Because this is what the locals want — to sit in front of the machine and zone out. These are not people who are flying into Vegas to lose everything they can in one weekend and then go home.

Brad Plumer:There have also been huge advances in payment systems to — essentially making it easier for people to put money in these machines.

Natasha Dow Schüll:: That's another level of smoothing, another way to make the experience more effortless. You just twist your hand, put in a $100 bill, get the credits and forget about them.

And what that does, it really just speeds things up. We haven't even talked about the addiction aspect. But these games are solitary, they're really fast, they're continuous and uninterrupted.

In a way, it's similar to how casinos try to avoid having pathways with right angles. Because what that does, that makes the consumer come to a stop and call on the decision-making part of their brains. Casinos don't want that. They want to curve you gently to where they want you to go. And it's the same thing with the money technology. They don't want you to make a decision about paying to gamble more. They want it to be so readily accessible at your fingertips that it's almost a non-decision to continue.

And this is why you see in various countries a discussion of whether those kinds of features are something that should be regulated. So there are ideas like slowing down the reel. Or things like reducing the amount of credit you can put into a machine, or forcing people to pay with cash.

Brad Plumer:Where are those regulatory discussions happening?

Natasha Dow Schüll:: Australia and Canada, mostly. You see long debates that themselves seem absurd, like should we slow the reels down to 2.1 seconds or 2.8? But that's because addiction is really about the intensity, the immediacy, the speed. Something happens right away, and then it can happen right away again.

Slot machines are like that. The event frequency is really intensified. On a slot machine you're playing up to 1,200 spins an hour. That's very different from a horse race or even a poker game, where you have to wait for the cards to come around. And every event that happens is another opportunity to reinforce the behavior. So that's where the addictiveness lies. It's solitary, continuous, and really rapid.

Brad Plumer: How would you characterize the regulatory environment in the United States? A lot more lenient?

Natasha Dow Schüll:: Oh yeah. Especially, post-2008, the idea is that state legislatures — whether its New Hampshire or Massachusetts — have gone through the trouble of loosening their standards to allow these machines. And once these bills pass it, no one wants these machines to fail.

And the regulators and legislators talk quite openly about this — you hear them at expos and conferences talk a lot about how it's a "partnership," how they need to work together to get innovations passed.

Brad Plumer:Your book suggests that player tracking is going to be the next big advance in the gaming industry. How so?

Natasha Dow Schüll:: It's really become super critical to the industry. If the industry is focused on regular customers or repeat players, they're going to need to get a sense of each individual's habits via data tracking, and then refine the way they market to that person.

And part of that involves mail marketing or offering bonuses. But in the future we're likely to see a shift to online or server-based games. And tracking will be critical there. So the way this might work is you sit down at a machine and it downloads particular games based on what it knows about you — the kind of games you would like, they sort of volatility you prefer.

Brad Plumer:It also seems that player tracking can be used to manage the moods of existing players. Like if you see that a player's having a bad streak, a casino worker can come by and offer a free drink or a free breakfast to perk them up and stop them from leaving.

Natasha Dow Schüll: We were talking about lax regulations and this is one perfect example of this. It is technically illegal for casinos to change the odds of game once you sit down and start playing.

But casinos can watch you play and, if they notice that you're nearing your pain point and about to leave, they can dispatch a "luck ambassador" to come give you a lunch bonus. And they can get around the rules about changing odds by classifying that as "marketing."

Although, casinos have actually found that those luck ambassadors backfired — a lot of players didn't want to be interrupted. So now they're trying to find better ways to do this. And recently there are some experiments with changing the machine mid-game. You can go in and change the volatility of the game while preserving the overall payback percentage. So you're taking a volatile machine and turning it into a smooth drip feed for a period — to get a player who's on a bad streak back on track.

And technically that circumvents the rules on changing the odds. And they're doing that by classifying some of these mathematical operations as "marketing" — even though they're actually changing the algorithm of the game.

Brad Plumer: Now walk me through the debate over addiction and problem gambling.

Natasha Dow Schüll: There are a couple different camps here. Some people — including the gaming industry — place the onus on managing the problem on the individual.

Typically, this side will also argue that there are a few poor souls out there who have just been dealt a bad hand and especially prone to addiction. If they weren't gambling they'd be doing something else. But, the argument goes, this is only 1 to 2 percent of the population. And everybody else can gamble with immunity.

I take a very different position in the book, which is that of course some people are more predisposed to these kinds of problems by virtue of biography or brain chemistry. But by the same token, certain technologies are more liable to addict. And I'd like to put some of the responsibility back there. The whole modus operandi of the industry is to approach the human being as something that's manipulable. So I find it disingenuous that they then turn around and argue that 100 percent of the responsibility for any harm is on the person.

Brad Plumer:So how do you address problem gambling? I mean in the book you describe a whole bunch of people who have real problems with this machine gambling — people who will spend days at end in the casinos, maxing out credit cards, neglecting their kids…

Natasha Dow Schüll: I do think in terms of treatment, once one is an addict, it's very important to do whatever works — whether that's Gambling Anonymous, therapy, possible medication, or just avoiding these kinds of environments.

But in terms of prevention, I do think regulation needs to be part of that discussion. There's no equivalent of the FDA for these machines. And I'm not holding up the FDA as some model of consumer protection, but these machines are affecting people far more than some over-the-counter drugs that are heavily regulated out there. It seems absurd that we draw a line between aspirin and these machines. And yet there's no discussion — because so much focus is on how people are choosing to spend money this way.

So I see my work as trying to open the door to discussion of this technology and to figure out whether some sort of accountability and regulation of it might be appropriate.

Brad Plumer:Are there regulations or preventions that have actually been shown to reduce problem gambling?

Natasha Dow Schüll:: So scholars have gone through the evidence on this, looking at various proposals, and some proposed fixes really do seem to backfire. For example, slowing down the reels might actually make people sit there longer. And that's the industry's position, that you can't fix this through the technology, because the addict will compensate by changing her own behavior.

But there's also evidence that some of these measures do work. So, for instance, if the time that people are spending on these machines is a problem, you cut people off after a certain amount of time. Some countries do this — the machine at least will beep some message saying you've been gambling for this long, would you like to take a break?

Some states like Massachusetts are experimenting with some other regulations. They'll make it easier for people to make pre-commitments. This is still pretty voluntary, but frequent players get incentives to go into these calendar models and say, okay, I only want to spend $200 today — after that the machine will freeze. So people are regulating themselves through self-tracking modules. That's one approach you see more and more.

Brad Plumer: Can't casinos use these player-tracking systems to figure out who's sliding into problem gambling and intervene?

Natasha Dow Schüll: That kind of thing was discussed in Massachusetts — but they eventually moved away from it. The idea is that casinos could track players to see when they are sliding into addiction. Because you can pick that up quite reliably with tracking. But then there's a tricky question of whether casinos have a legal duty of care to freeze up the machine or intervene when these patterns are detected.

Interview has been condensed and lightly edited for clarity.


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