From: Wade T. Smith (wade.t.smith@verizon.net)
Date: Mon 20 Jan 2003 - 15:36:56 GMT
Frontiers
by Gareth Cook
Speak, Memory
As certain as many of us are that we recall events when we were 3 or
even younger, scientific research suggests otherwise.
I was driving down the street when I glanced over and saw a tear
sliding down my wife's cheek.
"What if we die," she said, "and Aidan doesn't remember us?" Aidan is
our son. He just turned 1.
Even putting aside the morbid fear that something will happen to us - a
part of the mental illness called "parenthood" - it's a disturbing
idea. So much would vanish: watching trains, reading Goodnight Moon,
playing the game where I slice strawberries into a bowl and put it on a
low ledge for him to find.
I can tell him about these things when he is older, but he'll shrug. I
will probably forget most of them myself.
For scientists, memory is proving an elusive target. They are making
progress in understanding how the brain's development makes memory
possible. But it is also becoming clear that neuroscience alone can't
explain memory. Memory is tied to our ability to talk, to our ideas of
who we are, even to our place in the social universe. Sometimes we talk
about things so we'll remember them.
When Conor Liston was an undergraduate at Harvard, he did a simple
series of experiments that probed the beginnings of memory. The
results, published recently in the journal Nature, show that people
undergo a memory revolution at about age 1. And they show how difficult
memory is to capture in a lab.
Liston, who is now an MD/PhD student at Cornell University and the
Sackler Institute for Developmental Psychobiology, recruited groups of
very young children, aged 9 months, 17 months, and 24 months. He then
had them watch while an experimenter enacted a sequence of actions and
encouraged the children to copy them.
For example, the experimenter would say "Cleanup time!" while wiping a
table with a paper towel and then throw the towel into a wastebasket.
(At this age, obviously, children are too young to be given purely
verbal information to remember.) Then, four months later, the children
were invited back and given the props and the verbal cue (such as
"Cleanup time!") to see if they would reenact what they had seen
earlier. The older two groups did well, while the youngest group did
poorly: Something happens in those six months around the first birthday.
In his Nature paper, which he wrote with Harvard psychologist Jerome
Kagan, Liston suggests that the changes may have something to do with
the development of the frontal lobe, which is involved in many higher
functions of the brain.
But in looking for the origins of memory, he says, you can't just look
at the brain. For example, at 6 months, babies can remember events for
up to 24 hours. And at 9 months, they can remember events for up to a
month. But things leave the realm of today's neuroscience and become
almost philosophical when you ask the question "What is your earliest
memory?"
Liston says his first memory is standing with his mother and
grandmother, telling his grandmother what he wants for his third
birthday. He remembers his mother being pregnant and being mad at him
for issuing a set of birthday demands.
But conventional wisdom has it that most people can't remember much
that happened to them before about age 5. One reason is that it takes
children a while to discover the concept of self-identity: You can't
really remember things about yourself until you have a sense of who you
are.
Most children need to reach about 20 months before they will even pass
the "rouge test." Put a blotch of red on their nose and hold them up to
the mirror. If they reach for their real nose, not the one in the
mirror, it shows some rudimentary sense of self.
It takes longer, though, to develop the idea that you are a being,
separate from the world, that continues through time: Something
happened to me yesterday, the same me that is here now. This is so much
a part of how we adults think that it is difficult to imagine thinking
any differently. (Perhaps it could be said that all young children
experience Zen consciousness.)
Memory is also intertwined with language. Liston can't be sure whether
he is really remembering the scene at age 3 or just remembering a scene
constructed in his mind from conversations about it later.
Someday, I'm sure my wife or I will ask: "Do you remember, Aidan, how
you used to walk over here and pick strawberries from this bowl?" And
then we'll probably ask until he does remember.
Gareth Cook can be reached by e-mail at cook@globe.com.
This story ran in the Boston Globe Magazine on 1/19/2003. © Copyright
2003 Globe Newspaper Company.
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