That revelation was, er, revealed in Southern California this week at the Society for Neuroscience's annual meeting, which is taking place in sunny San Diego.
But we can take this lesson to heart in L.A., America's pot-shop capital.
According to a Harvard Crimson report on the study, "Those who began using pot before the age of 16 had more trouble focusing, learning from mistakes, and thinking abstractly than those who began afterwards."
Yeah, tell us something we don't know. After all, a near-majority of Californians favor legalizing pot, but the state's marijuana legalization initiative did not pass earlier this month.
Lead author Staci A. Gruber, director of the Cognitive and Clinical Neuroimaging Core at McLean Hospital, says."The more and the earlier you smoke, the worse you perform on these tasks."
Tasks such as ... voting.