Ego depletion is a concept from Thinking Fast and Slow that I think is very broadly written about in other contexts and useful in general.
Across different studies and experiments, behavioral economists (like psychology but fancy) found that there’s a connection between tasks that are:
- intellectually challenging
- physically taxing
- reliant on willpower
Namely, that all three types of activities will interfere with one another when performed in tandem or in sequence. This would point towards the existence of a shared pool of energy that all of these types of activities draw on. (It might be glucose in the brain but that’s not fully confirmed.)
David Allen’s Getting Things Done methodology is based around a concept of psychic ram: that things you’re thinking about but haven’t adequately captured are a drain on your mental resources and cause you to be less efficient overall.