There's a guy who did a drug abuse study on rats but not locked in cages. his theory was that being locked in a cage was different than being in a social envir

There's a guy who did a drug abuse study on rats but not locked in cages. his theory was that being locked in a cage was different than being in a social environment. So he built a habitat where rats could socialize with each other, use hamster wheels, and run around obstacles. In this population he found that almost NONE of the rats did harmful amounts of the narcotics-laced water. (He was using opiates as his "drug of choice.") So his theory is that a) many animal models of addiction are wrong because they use animals in very confined spaces b) maybe people who feel "trapped" in their life are more prone to developing addiction, and we should be treating addiction as a social disease.