Nobody believes weed will make you better at studying.
Nobody.
Nobody.
FWIW, I am very selective with my strains - only certain types actually help, and my dosage is mild enough to not have strong psychoactive effects (higher CBD-strains). Medical cannabis has truly had a significant impact on the trajectory of my life.
Out of curiosity, what are those? I'm not an expert and I'm really only aware of the sativa/indica divide.
Here's a description of how CBD differs from THC: https://www.leafly.com/news/cannabis-101/whats-the-deal-with... and I can attest to what it says. I don't like feeling high, but I do like feeling mellow. It's sort of like the difference between having a glass of wine and pounding shots to me.
They believe it's helpful to their life in general, which this study isn't measuring. Nobody in their right mind smokes weed to improve their GPA.
Plenty of people believe this.
Subduing default mode network provides a pathway to concentration, if one's mind is set on it, like reading the book or going over the test question bank. But it could also be squandered on other activities unrelated to learning.