Hmm...I don't know if psychedelics usage made much permanent change in my consciousness...
I'm given to understand some people find a very small LSD dose helps them to figure out math. Considering the wobbly status of my brain chemistry, I may or may not try something similar when I go beat my head against al-gibberish...a learning disability leads to contemplating desperate measures?
Considering the visuals from cacti products are particularly supposed to be geometric, while 'shrooms seem to distort one's time-sense and the visuals are more circular in nature...that suggests what ought to be tried?
But basically psychedelics...I'm given to understand, cause a serotonin/dopamine dump, as well as working as a novel neurotransmitter-that rather overwhelms our brain and can fry it...as in induce permanent depressive episodes in people who weren't prone to them, or psychotic episodes, again in people who weren't having them.
And maybe that's the dosage. My happy pills, if I took a whole bunch of them, would frak me up royally. Maybe a microdose of psychedelics has a different effect than a "party" dose.
I think we grew more brain because the smarter we got, the more fatty foods we were able to get, and the more fatty foods we could eat, the more brain we were able to grow...reinforcing feedback loop. I doubt psychedelics had that much effect on brains themselves.
Now influencing our culture??? That's a whole different trip, man.