Alan Dix’s book (aptly named “Human Computer Interaction”) is quite good, even if somewhat old by now. HCI is an actual academic discipline with, yes, tons of theoretical and empirical results that govern what a good UI should be. Many of which are indeed grounded in psychology, others in physiology, etc (what we call Human Factors). There is a whole special interest group of the ACM just about it: SIGCHI.
Do not confuse this with fashion/trends/taste. These change, resulting in widely different possible flavors of UI over the years. But the underlying principles are the same.
Another thing to remember is that the fact that Apple, Google, or someone else implemented an UI in a certain way doesn’t mean they are following best practices and guidelines. Novelty sells, even if at the end of the day it does a worse job of things…
Edit: added link to SIGCHI
OTOH, if you build a playlist manager for playlists everyone can add to, you make sure nothing anyone adds will break it…