It dawned on me later that we also phrase graph titles like this, and that maybe I'd been puzzled because I was thinking of the wrong sense of the word. I guess we'd all figure we know what this graph - showing how increasing obsession maps onto your precision - would look like. Caring about your results will make you better but only up to a certain point. Like the eponymous CK scent, obsession can be enhancing but too much will make you stink. (At least, it will make people wrinkle their noses and wonder if they should clue you in.)
I was kind of boggled by the idea of making the call on how obsessed is too obsessed, and I wondered how a scientist would even measure that. And then I remembered something I saw in the paper that morning: the Curiosity Shop pop-up. It's a travelling booth put on to educate Ontarians about what researchers do; they take folks' questions for scientists and get back to you with answers. I thought it was neat when I read it but I never imagined I'd have something to ask them. Mere hours later, I was racing from work to make it to their gig at the Metro Convention Centre. I was too late. When I got home I banged out an email. So, I've sent my question off to them and I'll let you know if I get an response!