I'm quite interested in my own mental processes, simply because I'm a failed scientist, and because I'm interested in how the brain and the mind works, and I like to avoid easy descriptions.
The systematic experimental study of reproducible errors of human reasoning, and what these errors reveal about underlying mental processes, is known as the heuristics and biases program in cognitive psychology. This program has made discoveries highly relevant to assessors of global catastrophic risks.
I was interested in the nature of human mental processes, which is what got me interested in psychoanalysis. And it became clear to me after a while that mental processes come from the brain, and in order to understand them, you need to be a biologist of the brain.
Words for mental processes are all derived from physical things.
The results of ethnic psychology constitute, at the same time, our chief source of information regarding the general psychology of the complex mental processes.
On the other hand, ethnic psychology must always come to the assistance of individual psychology, when the developmental forms of the complex mental processes are in question.