Given how important o-3 is to cell membranes (even if o-3 did not reduce inflammation) and how important cell membranes probably are to brain function, reducing -6 intake is unlikely to have a strong cognitive benefit. According the my amateurish models, the most important way keeping o-6 intake low impacts cognition for a young guy like you is by slowing the rate at which your brain will deteriorate over the decades. In other words, the inflammation reduction is caused by a reduction in prostaglandins, which are synthesized from fatty acids, where prostaglandins have no particular role that I know of in the maintenance of cell membranes -- they're paracrine hormones.