My visceral, unadulterated response to the interviewer (and the Bridgewater process) is that they are assuming some high mental barrier of entry to their process of reasoning. However, you have displayed here that this is not the case. It only took you 40 minutes to grasp the concept very well from what I can tell. Doesn’t this make their screen (whether or not you happen to have learned this process of thinking, which is determined by the chance happenings of your educational life) arbitrary? If they can teach it so rapidly why not just ale massive cohorts into training, teach them the process and then test to see who retains it the best? I suppose I like the simplicity and lack of formal nonsense in their interview process but again, I think you could teach what they are screening for so easily it makes the effort somewhat futile. Thank you for sharing your experience though, this was a good read.