Does Marijuana Make You Stupid and Does It Help with Priming and Finding Associations?

From "Does Marijuana Make You Stupid" on Wired Science: The Frontal Cortex: "The scientists found that “there were no significant between group differences.” In other words, the amount of pot consumed had no measurable impact on cognitive performance. The sole exception was performance on a test of short-term verbal memory, in which “current heavy users” performed slightly worse than former users. The researchers conclude that, contrary to earlier findings, the mind altering properties of marijuana are ephemeral and fleeting:

The adverse impacts of cannabis use on cognitive functions either appear to be related to pre-existing factors or are reversible in this community cohort even after potentially extended periods of use. These findings may be useful in motivating individuals to lower cannabis use, even after an extensive history of heavy intake.

This study builds on previous work by Harvard researchers demonstrating that the learning and memory impairments of heavy marijuana users typically vanish within 28 days of “smoking cessation.” (The slight impairments still existed, however, one week after smoking.)


Interestingly, the scientists found that marijuana seems to induce a state of hyper-priming, in which the reach of semantic priming extends to distantly related concepts. As a result, we hear “dog” and think of nouns that, in more sober circumstances, would seem rather disconnected, such as “leash” or “hair.” This state of hyper-priming helps explain why cannabis has been so often used as a creative fuel, as it seems to make the brain better at detecting those remote associations that lead to radically new ideas."