After reading this thread on Hacker News I am realizing that as a self-taught designer, I should know more about actual objective research on best practices.

I was wondering if anyone could recommend any books that would help with explaining or justifying design decisions, such as "such and such study showed that having a button this size makes this happen" or "the maximum recommended number of options to show at a time is 5 because of such and such study".

Thanks!