`with_milk` and `with_sugar` are booleans that people have (lots of) experience with. this seems to help us think about this stuff – we've seen how milk/sugar "

`with_milk` and `with_sugar` are booleans that people have (lots of) experience with. this seems to help us think about this stuff – we've seen how milk/sugar "work" many times, and we've already internalized some model of that situation – we already "get it" on an intuitive level. hence, reusing that model for general Boolean variables reduces the cognitive effort required[0]. for a similar example, see [1]. summary: a study presented people with a logical problem. they failed miserably if the question was about abstract math-y stuff, but got it right most of the time if the variables were like `X is underage` and `X can buy beer` (explained in the "Policing social rules" section) --- [0] as a bonus, we can quickly sanity-check if our reasoning is correct – if there's `no (milk or sugar)` in my coffee, there's obviously `(no milk) and (no sugar)` in it! [1] https://en.m.wikipedia.org/wiki/Wason_selection_task https://en.m.wikipedia.org/wiki/Wason_selection_task