Well posting to the BS section often has me ransacking my mental trove of trivia AND looking things up, often extensively, yet some would say that it's still a confounded bloody waste of time. You're making a case, but you haven't presented any evidence that what you say is borne out. I'm not saying you're wrong, but I am sceptical. Yes, crosswords and chess engage the brain for a while as you're doing them, but lasting benefits? Evidence please!