Are you unfamiliar with my research?
Also, weed, no different from usual.
The funny part is that I can do triple digit multiplication in my head after a dozen bong rips. I'll do it successfully and I'll do it faster than most people could do it on their phone (assuming phone in pocket or nearby/at hand, phone must be unlocked, calculator app must be accessed, etc.).
I acknowledge it probably is responsible for my train of thought becoming derailed on occasion, but other than that, it has no clear negative effect on my cognitive performance.