@DaveHiggins There may be something in it. I notice that significant aspects of my philosophical development only really happened during a period when I was working in a job which included a lot of repetitive and dull manual work, rather than during the five years I studied philosophy at university. But I think getting even good qualitative data on that sort of experience is fraught with problems. You'd have to do a long study with detailed interviews. Quantifying it seems almost impossible.