Wasn't there a guy who did the "rats prefer cocaine to food" study but without having the rats isolated in individual cages, and it turns out that no, they don't actually prefer cocaine to food when they aren't (essentially) in solitary?
You’re talking about the Rat Park study. That one is also controversial and hasn’t successfully replicated. Personally I think the general idea of a connection between emotional trauma and addiction is pretty obvious, but also a but more complex than the Rat Park study implies or assumes.
To be clear, lots of studies have shown that animals in richer environments do less drugs; though the effect doesn't seem to be as strong as Alexander claimed.
