How much would you pay to have a small memory chip implanted in your brain if that chip would double the capacity of your short-term memory? Or guarantee that you would never again forget a face or a name?

There’s good reason to consider such offers. Although our memories are sometimes spectacular  we are very good at recognizing photos, for example  our memory capacities are often disappointing. Faulty memories have been known to lead to erroneous eyewitness testimony (and false imprisonment), to marital friction (in the form of overlooked anniversaries) and even death (sky divers have been known to forget to pull their ripcords  accounting, by one estimate, for approximately 6 percent of sky-diving fatalities). The dubious dynamics of memory leave us vulnerable to the predations of spin doctors (because a phrase like “death tax” automatically brings to mind a different set of associations than “estate tax”), the pitfalls of stereotyping (in which easily accessible memories wash out less common counterexamples) and what the psychologist Timothy Wilson calls “mental contamination.” To the extent that we frequently can’t separate relevant information from irrelevant information, memory is often the culprit.

All this becomes even more poignant when you compare our memories to those of the average laptop. Whereas it takes the average human child weeks or even months or years to memorize something as simple as a multiplication table, any modern computer can memorize any table in an instant  and never forget it. Why can’t we do the same?

Much of the difference lies in the basic organization of memory. Computers organize everything they store according to physical or logical locations, with each bit stored in a specific place according to some sort of master map, but we have no idea where anything in our brains is stored. We retrieve information not by knowing where it is but by using cues or clues that hint at what we are looking for.