Opening Skinner's Box: Great Psychological Experiments of the Twentieth Century Highlight

This rather stunning finding shows, perhaps most clearly of all, how rats, when in a “friendly” place, will actually avoid anything, heroin included, that interrupts their normal social behaviors. The rats liked the sweetened water, so long as they didn’t get stoned. At least in rodents, opiates are actually, in favorable situations, distinctly undesirable, which is a far cry from our understanding of them as inherently tempting.