Rat Park

Rat Park was a series of studies into drug addiction conducted in the late 1970s and published between 1978 and 1981 by Canadian psychologist Bruce K. Alexander and his colleagues at Simon Fraser University in British Columbia, Canada.

[1] To test this hypothesis, Alexander and his colleagues built Rat Park, a large housing colony 200 times the floor area of a standard laboratory cage.

[1] This research highlighted an important issue in the design of morphine-self administration studies of the time, namely the use of austere housing-conditions, which confound the results.

These animals rejected the morphine solution when it was stronger, but as it became sweeter and more dilute, they began to drink almost as much as the rats that had lived in cages throughout the experiment.

In another experiment, he forced rats in ordinary lab cages to consume the morphine-laced solution for 57 days without other liquid available to drink.

There were "some minor withdrawal signs, twitching, what have you, but there were none of the mythic seizures and sweats you so often hear about ..."[2] The authors concluded that isolated cages, as well as female sex, caused an increased consumption of morphine.

[6] The study was not able to replicate the results, and the author suggested that strain differences between the rats Alexander's research group used could be the reason for this.

However, some researchers have shown an interest in "conceptual" replication to continue exploring the contribution of environmental and social enrichment to addiction.

[17] The YouTube channel Kurzgesagt created and published a video based on Hari's book, which garnered over 19 million views.