Harvard psychologist Daniel Wegner—and his colleagues Ralph Erber and Paula Raymond—first began to systematically explore “transactive memory” back in the ’80s. Wegner noticed that spouses often divide up memory tasks. The husband knows the in-laws’ birthdays and where the spare light bulbs are kept; the wife knows the bank account numbers and how to program the TiVo. If you ask the husband for his bank account number, he’ll shrug. If you ask the wife for her sister-in-law’s birthday, she can never remember it. Together, they know a lot. Separately, less so.
Wegner suspected this division of labor takes place because we have pretty good “metamemory.” We’re aware of our mental strengths and limits, and we’re good at intuiting the memory abilities of others. Hang around a workmate or a romantic partner long enough and you discover that while you’re terrible at remembering your corporate meeting schedule, or current affairs in Europe, or how big a kilometer is relative to a mile, they’re great at it. They’re passionate about subject X; you’re passionate about subject Y. So you each begin to subconsciously delegate the task of remembering that stuff to the other, treating one’s partners like a notepad or encyclopedia, and they do the reverse. In many respects, Wegner noted, people are superior to notepads and encyclopedias, because we’re much quicker to query: Just yell a fuzzily phrased question across to the next cubicle (where do we keep the thing that we use for that thing?) and you’ll get an answer in seconds. We share the work of remembering, Wegner argued, because it makes us collectively smarter.