The difference in standard deviations is not, from a theoretical perspective, all that strange a phenomenon: at the very beginning of this page, I covered some basic principles of nootropics and mentioned how many stimulants or supplements follow a inverted U-curve where too much or too little lead to poorer performance (ironically, one of the examples in Kruschke 2012 was a smart drug which did not affect means but increased standard deviations).
To our Brainfood students and youth supporters: It’s your potential that inspired us, your laughter that sustained us, your incredible talent that challenged us to dig deep and build programs that you deserve. Whether you were with us for one year or one week, know that there’s probably a Brainfood staffer who has bragged about how awesome you are. We hope that what you learned in Brainfood sticks with you, even if it’s just using that pumpkin chocolate chip muffin recipe to make someone’s day a little brighter. You’ve given us hope and made us so very proud. Thank you. Now go out there, get what’s yours, and bless the world with your many, many talents.

Took pill 12:11 PM. I am not certain. While I do get some things accomplished (a fair amount of work on the Silk Road article and its submission to places), I also have some difficulty reading through a fiction book (Sum) and I seem kind of twitchy and constantly shifting windows. I am weakly inclined to think this is Adderall (say, 60%). It’s not my normal feeling. Next morning - it was Adderall.
Some nootropics users are hopeful that the drugs could be permanently “neuroprotective”—in other words, that the compounds could slow down the neuronal aging process, and help avoid cognitive deterioration later in life. (For what it's worth, most of the users I spoke to said that didn't matter much to them. “I doubt anything I’ve tried has made me smarter in a long-term way,” Baker says. “That’s still science fiction.”)
Amphetamine – systematic reviews and meta-analyses report that low-dose amphetamine improved cognitive functions (e.g., inhibitory control, episodic memory, working memory, and aspects of attention) in healthy people, and in individuals with ADHD.[21][22][23][25] A 2014 systematic review noted that low doses of amphetamine also improved memory consolidation, in turn leading to improved recall of information in non-ADHD youth.[23] It also improved task saliency (motivation to perform a task) and performance on tedious tasks that required a high degree of effort.[22][24][25]