> What does one do with an intellectual life other than swimming through intellectual content?
Psychology: I've used it.
HEXACO/Big 5, I've used it to find my girlfriend and test on compatibility. How do you do that? Well, I score high on "openness to experience", I can spot other open people from a mile away. Conscientious vs non-conscientious people are also quite easily recognizable by how rigid/organized they are. When a person disagrees sometimes and agrees a few times then they're moderately agreeable. Extraversion/introversion is easy to spot as well. Neuroticism is harder to spot but anxiety (or lack thereof) is correlated. There! No questionnaire needed! Though, when I knew my GF for 3 months I also gave her a questionnaire for fun which was stating the obvious: her personality was like mine. The most fun way in which you can see that is by looking at both our YouTube feeds, it's quite similar.
Priming: the idea of priming is nebulous due to the publication crisis, but it did teach me to care about the atmosphere you're setting.
Statistics: using statistics in psychology made me better at data science
Neuropsychology: one topic raised interesting questions, which was: can we want something and hate it (yes!)? Can we like something and not want it (yep)? This taught me a lot about certain aspects of addiction.
Neuroplasticity: awesome concept. Neuroplastic behavior has been observed in meditators and hardcore gamers. My guess is that anything you'll do intensely for a few hours will change your brain somewhat.
The publication crisis: many things in psychology are bullshit because there's too much of a publish/perish culture and because of that reproduction of research is an issue. This is especially why you need to put whatever research you read into practice. By using it yourself, you'll find out quickly whether it's research you can meaningfully build on yourself.
Intuition: you can trust your intuition iff (1) you've had many examples of whatever you're intuiting about, (2) the rules were structured like chess or poker (expected value + law of large numbers is needed -- see (1) ) and (3) you can sense you're own intution in the first place. Because of this I immediately realized that people that say "yup I'm good with people" might make the catastrophic flaw of thinking that they're also good with people from an entirely different culture! I've seen this happen up close. The reason is simple: you haven't seen anyone from an entirely different culture, so whatever intuition you have I would not trust it.
Just some thoughts about psychology. I've been an enthusiast about psychology for about 15 years and got academically schooled in it 10 years ago.