"Just as we learn through transactive memory who knows what in our families and offices, we are learning what the computer 'knows' and when we should attend to where we have stored information in our computer-based memories," Sparrow wrote.
You could say this is precisely what we most fear: Our mental capacity is shrinking! But as Sparrow pointed out to me when we spoke about her work, that panic is misplaced. We've stored a huge chunk of what we "know" in people around us for eons. But we rarely recognize this because, well, we prefer our false self-image as isolated, Cartesian brains. Novelists in particular love to rhapsodize about the glory of the solitary mind; this is natural, because their job requires them to sit in a room by themselves for years on end. But for most of the rest of us, we think and remember socially. We're dumber and less cognitively nimble if we're not around other people — and, now, other machines.
In fact, as transactive partners, machines have several advantages over humans. For example, if you ask them a question you can wind up getting way more than you'd expected. If I'm trying to recall which part of Pakistan has experienced tons of U.S. drone strikes and I ask a colleague who follows foreign affairs, he'll tell me "Waziristan." But when I queried this online, I got the Wikipedia page on "Drone attacks in Pakistan." I wound up reading about the astonishing increase of drone attacks (from one a year to 122 a year) and some interesting reports about the surprisingly divided views of Waziristan residents. Obviously, I was procrastinating — I spent about 15 minutes idly poking around related Wikipedia articles — but I was also learning more, reinforcing my generalized, "schematic" understanding of Pakistan.