[tt] NYT Mag.: Total Recall

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Total Recall
http://www.nytimes.com/2008/04/13/magazine/13wwln-essay-t.html

Idea Lab
By GARY MARCUS

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.

In the best-case situation, this process works well: the particular
memory we need just "pops" into our minds, automatically and
effortlessly. The catch, however, is that our memories can easily
get confused, especially when a given set of cues points to more
than one memory. What we remember at any given moment depends
heavily on the accidents of which bits of mental flotsam and jetsam
happen to be active at that instant. Our mood, our environment, even
our posture can all influence our delicate memories. To take but one
example, studies suggest that if you learn a word while you happen
to be slouching, you'll be better able to remember that word at a
later time if you are slouching than if you happen to be standing
upright.

And it's not just humans. Cue-driven memory with all its
idiosyncrasies has been found in just about every creature ever
studied, from snails to flies, spiders, rats and monkeys. As a
product of evolution, it is what engineers might call a kluge, a
system that is clumsy and inelegant but a lot better than nothing.

If we dared, could we use the resources of modern science to improve
human memory? Quite possibly, yes. A team of Toronto researchers,
for example, has shown how a technique known as deep-brain
stimulation can make small but measurable improvements by using
electrical stimulation to drive the cue-driven circuits we already
have.

But techniques like that can only take us so far. They can make
memories more accessible but not necessarily more reliable, and the
improvements are most likely to be only incremental. Making our
memories both more accessible and more reliable would require
something else, perhaps a system modeled on Google, which combines
cue-driven promptings similar to human memory with the
location-addressability of computers.

However difficult the practicalities, there's no reason in principle
why a future generation of neural prostheticists couldn't pick up
where nature left off, incorporating Google-like master maps into
neural implants. This in turn would allow us to search our own
memories -- not just those on the Web -- with something like the
efficiency and reliability of a computer search engine.

Would this turn us into computers? Not at all. A neural implant
equipped with a master memory map wouldn't impair our capacity to
think, or to feel, to love or to laugh; it wouldn't change the
nature of what we chose to remember; and it wouldn't necessarily
even expand the sheer size of our memory banks. But then again our
problem has never been how much information we could store in our
memories; it's always been in getting that information back out --
which is precisely where taking a clue from computer memory could
help.

Gary Marcus, professor of psychology at New York University, is the
author of Kluge: The Haphazard Construction of the Human Mind.