What you've heard
Rat Park proved addiction is about the cage, not the drug
Verdict
Overstated
Overstated. Environment matters a great deal, as the Vietnam veterans show, but the cage is not the whole story: drugs are rewarding in any cage.
Did Rat Park prove addiction is about the cage?
Overstated. Environment matters a great deal, as the Vietnam veterans show, but the cage is not the whole story: drugs are rewarding in any cage.
In the late 1970s the psychologist Bruce Alexander housed some rats alone in standard cages and others together in a large, open "Rat Park", and gave them morphine solution to drink. The isolated rats drank more, and the story has been retold as proof that addiction is purely a product of a poor environment. The studies were tiny and measured drinking differently in the two settings, the Rat Park rats did drink morphine, and the original papers drew no lessons for humans. A later attempt to repeat the key result failed, and heroin and cocaine proved rewarding to rats whether housed alone or in groups. Better-designed work has since shown that, given a choice between a drug and contact with another rat, most rats chose the contact.14
Where the book tests it
Sources
- 14.Alexander, B.K., Coambs, R.B., and Hadaway, P.F. (1978). "The effect of housing and gender on morphine self-administration in rats." Psychopharmacology, 58(2), 175-179. https://doi.org/10.1007/bf00426903 ; Gage, S.H., and Sumnall, H.R. (2019). "Rat Park: how a rat paradise changed the narrative of addiction." Addiction, 114(5), 917-922. https://doi.org/10.1111/add.14481 ; Petrie, B.F. (1996). "Environment is not the most important variable in determining oral morphine consumption in Wistar rats." Psychological Reports, 78(2), 391-400. https://doi.org/10.2466/pr0.1996.78.2.391 ; Bozarth, M.A., Murray, A., and Wise, R.A. (1989). "Influence of housing conditions on the acquisition of intravenous heroin and cocaine self-administration in rats." Pharmacology Biochemistry and Behavior, 33(4), 903-907. https://doi.org/10.1016/0091-3057(89)90490-5 ; Venniro, M., Zhang, M., Caprioli, D., Hoots, J.K., et al. (2018). "Volitional social interaction prevents drug addiction in rat models." Nature Neuroscience, 21(11), 1520-1529. https://doi.org/10.1038/s41593-018-0246-6 (the first Rat Park study used 32 rats, and intake was measured by weighing bottles in cages but counting drops in the park.)
Note numbers are those of Chapter 14, Wanting, Loving, Losing, Meaning.
This verdict is one of the "What you've heard" boxes in Chapter 14, Wanting, Loving, Losing, Meaning, where the book tests the claims people repeat against the studies behind them.
Educational content, not medical advice. Disclaimer.