A great article on the growth of gambling in the UK, The best chance you'll get?
When one of Skinner's rats pressed a lever, it was given a food pellet. By experiment Skinner then established that if a pellet was delivered only on the 10th press of the lever, the rat would quickly learn to press the lever 10 times. If, however, a random element was introduced to the lever-pressing, whereby a pellet was still introduced on average one in 10 times, but sometimes delivered twice or three times in a row and sometimes not for 20 or more presses, the rat apparently became obsessed with the lever-operation itself.
I'd love to be in that UK Labour Cabinet when they discussed the 2005 Gambling Act, to see who if anyone had any moral fibre to stand up against it. Yeh Yeh, freedom of choice for consumers and individuals, and if people are stupid enough to become addicted than it's their own fault.