for The Outline

In 1979, Bruce Alexander, a researcher at Simon Fraser University, separated rats into two cages, a stimulating one and an isolated one, and gave them morphine in order to measure the effect of environment on addiction rates.

The so-called “Rat Park” experiment was intended to debunk some of the flawed understanding around addiction at the time, specifically the notion that the drug itself was the most important factor in whether someone became addicted. The rats in both cages became physically dependent on the morphine, but the Rat Park rats consumed less morphine than the group in the boring cage. “Addiction isn’t you — it’s the cage you live in,” Alexander concluded.

The Rat Park study was flawed in its design and its findings, however, and it was ignored for almost three decades — until a group of experts rediscovered and started promoting it around 2008. The Rat Park study undermined one popular misconception about addiction, that chemistry of drugs is the single most important factor in addiction. But instead of pushing the popular understanding forward, it merely replaced that misconception with a new one: that environment is the most important factor. (continued)