The experiment is simple. Put a rat in a cage, alone, with two water bottles. One is just water. The other is water laced with heroin or cocaine. Almost every time you run this experiment, the rat will become obsessed with the drugged water, and keep coming back for more and more, until it kills itself. But in the 1970s ... Bruce Alexander noticed [that] the rat is put in the cage all alone. It has nothing to do but take the drugs. What would happen, he wondered, if we tried this differently? So Professor Alexander built Rat Park. It is a lush cage where the rats would have colored balls and the best rat-food and tunnels to scamper down and plenty of friends. The rats with good lives ... mostly shunned [the drugged water]. While all the rats who were alone and unhappy became heavy users, none of the rats who had a happy environment did. Professor Alexander argues [that] addiction is an adaptation. It's not you. It's your cage. This gives us an insight that goes much deeper than the need to understand addicts. The opposite of addiction is not sobriety. It is human connection. This isn't [just] theoretical. 15 years ago, Portugal had one of the worst drug problems in Europe, with one percent of the population addicted to heroin. They had tried a drug war, and the problem just kept getting worse. So they decided to do something radically different. They resolved to decriminalize all drugs, and transfer all the money they used to spend on arresting and jailing drug addicts, and spend it instead on reconnecting them to their own feelings, and to the wider society. The results? Since total decriminalization, addiction has fallen, and injecting drug use is down by 50 percent.