Here is some research around the alcohol effect. What I found most surprising is the mean consumption was over 80g, since 8g of ethanol is a unit that's an astonishing mean of 10units.
I was of the impression that the effect was around 1 unit.
I actually hadn't realized until I went looking that the "standard drink" isn't much of an international standard unit at all. Will have to keep that in mind when reading papers/recommendations from different health authorities in the future.
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Anyway, it's pretty interesting. I'm not sure I'm going to believe the effect just on one noisy study, but even if the reality is something lesser - like it just not harming memory formation of things you'd learned earlier in the day, the implications are still a bit interesting.
It certainly adds a bit to some of the historical social biases against "day drinking", and also does a bit to explain how plenty of high-performing young people seem to use alcohol pretty heavily after they're done learning (college students partying, etc) with limited direct impacts on their educational performance.