Sunday, December 24, 2017

Rat Park: False for Rats but True for Humans

Rat Park was a series of experiments done by Bruce Alexander on rats and drug addiction. Bruce Alexander was skeptical of earlier experiments, in which rats were given extremely bare environments and no real alternatives to pushing the drug lever. Predictably these rats had a tendency to just repeatedly hit the drug lever. Alexander gave his rats larger environments with more toys and tunnels, even other rats. Supposedly the rats with the more enriched environment used less drugs than the ones in the bare environment. suggesting that a mere lack of alternatives was to blame. It's not that the drugs themselves are hopelessly addictive, it's just that for those rats there was nothing else to do.

Except maybe rat park didn't replicate. The Wikipedia page still incorrectly states that it failed to replicate. It's true that some attempts to replicate failed. But there were several successful attempts to replicate it, too.

Maybe the rat park effect is real, and maybe it's not. I really don't know, and I don't particularly care. I actually don't think that animal studies are particularly useful for learning about addiction in humans. Human beings have foresight and planning. A rat pressing a lever never has the thought, "This will leave me with an incapacitating hangover that will preclude my working tomorrow. My boss will catch on if this becomes a pattern. So I need to either stop completely or have a strict, disciplined schedule for my bad habit that I never deviate from." The rat doesn't think, "If I pull the lever now, I won't be able to pick up my kid from daycare and my other kid from kindergarten." Intoxication makes the typical habits of a normal life unfeasible for most people. In contrast, the rats might get intoxicated but not be incapacitated in any meaningful sense. They don't perform complex tasks, coordinated with a few fellow rats for the benefit of other rats in a vast rat economy. Drug use patterns in human beings is going to be a lot more complicated than drug use patterns in rats. Even addicts often make rational choices to abstain, even for a fairly trivial reward.

I actually think that "total drugs used" might not be the correct measure here, if we're trying to measure dysfunction due to drug use. The rats in the enriched environment might consume the same amount of cocaine (or perhaps even more), but burn off the excess energy and direct it toward "pro-social" goals. The rats in the bare environment might screw themselves up on a smaller dose. I don't know how anyone would do this. Again, rats don't really have a functioning economy, so maybe it's hard to tell a "well-functioning" rat from his dysfunctional nearly-identical twin in another cage. I'm also reminded of a comparison of two human cultural groups from a Thomas Sowell book, one of which drank more total alcohol than the other. But the group that drank less alcohol had more alcoholics and alcohol-related social problems. The group that drank more had a lot of casual drinking, but very little drinking to excess. (I wish I had a more precise reference, but this is probably from his "...and Cultures" trilogy.) So plainly, in humans if not in rats, the total volume consumed is not the proper measure of social dysfunction.

The scientific debate over rat park is interesting, and I'll follow it for any definitive signs of a clear verdict. But it's ultimately a little silly. The lessons of rat park may or may not be true for rats, but they are definitely true for humans. Human beings weigh the salient alternatives and adjust carefully to incentives, even if rats don't.

See an excellent recent piece by Scott Alexander, called Against Rat Park. I suppose that title would fit for this post, too, but I'm making a very different point. Scott discusses Ogedei Khan, a son of Genghis who was at the top of the world. He nevertheless drank himself to death. Supposedly this goes against rat park because it proves that people with very (very) enriched environments are still susceptible to drug abuse problems. I draw a different lesson. If you're at the top of the world, you can afford a costly drug habit. Ogedei wasn't about to get "fired" from being Genghis' son. Certainly some people do wreck their lives with an uncontrolled drug habit, but that prospect keeps most of us in line. "Celebrities with drug problems" is a cliche. These are people who certainly work hard and put in a lot of hours while they are working on a project (say, a movie or a concert tour). But they also have a lot of "down time" and face little social censure for indulging a drug habit. So it's not that propensity to consume drugs is a simple monotonic function of social status, declining with rising status. It's not simply that desperation drives people to drug use. For some people, a drug habit would categorically change their life. They'd have to give up most of the good things (job, family, school) in order to accommodate it. I think this is a more useful way to think about what drives some people to drugs and deters others.

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