will become addicted to cocaine in the water and other drugs to the degree that they would and I of course the obvious assumption is that the substances were to blame for the addiction then in 1970 Bruce Alexander who is a scientist at the time mean interesting observation these rats who are addicted to the substances were placed in cages alone so we thought to himself was the next logical thing to do test whether substances are in fact blame for addiction ha let's put these rats and mice cages with friends.