https://en.wikipedia.org/wiki/Rat_Park#Reaction_to_the_exper... http://www.ncbi.nlm.nih.gov/pubmed/9148292?dopt=Abstract

I should say, the results have not been replicated. There's only been a few attempts. Maybe the replicators screwed up!

To quote the root article: "But ultimately I should be able to replicate your findings and you should be able to replicate my findings, otherwise it’s not science, it’s bullshit."

So far Rat Park has not be replicated.