Some scientists did a study trying to determine whether or not marijuana is addictive. They allowed monkeys to push a button which caused them to be injected with THC. The study found that the monkeys pushed the button up to 30 times when THC was being injected, but only 1-4 times when water was being injected. This led some researchers to believe that marijuana might indeed be addictive.

This kinda sounds like a no-brainer. No shit they injected themselves more with THC than water. If I had an IV hooked up to my arm, and simply had to push a button to get injected with THC, you're damn straight I'd be pushin' it all the time. And if it was battery acid rather than THC, I'll bet I'd push the button fewer times. :)

Stolen by stoned monkeys from NeoFlux.