You sure you knew the same guy? My working memory is crap, and, presumably, getting worse. ;)

I find that functional programming really cuts down on the amount of mental state I need to maintain. So while I'll have some API docs and another module or two open for reference, I don't need to worry about what that variable gets set to two pages above.

Maybe avoiding that kind of unnecessary detail makes one's unconscious better able to work on the program too. Still learning about this: http://joeyh.name/blog/entry/on_not_coding_late/