won some money — or you got nothing. That sort of game was only mildly profitable, and had limited appeal to players.

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.

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 theaddictive 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."

(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.)

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.

In the United States, meanwhile, Schüll argues that regulations remain lenient.