My digit span, the gold standard by which working memory is measured, had doubled from nine to eighteen. Compared with my tests almost a year earlier, I could recall more lines of poetry, more people’s names, more pieces of random information thrown my way. And yet a few nights after the world championship, I went out to dinner with a couple of friends, took the subway home, and only remembered as I was walking in the door to my parents’ house that I’d driven a car to dinner. I hadn’t just forgotten where I parked it. I’d forgotten I had it. That was the paradox: For all of the memory stunts I
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