BrainStuff Classics: Why Can't People Remember Being Born?

You probably remember your last birthday, but not your first – or your zeroth. Learn why scientists think we lose those early memories in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:02):
Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff,
I'm Lauren Vogelbam, and I've got another brain Stuff classic
for you. Our former host, Christian Sagar, explores the puzzling
question why can't people remember being born? Hey, I'm Christian

(00:23):
Sagar and welcome to brain Stuff. A lot of things
are easy to remember. My high school graduation, for instance,
or my first summer job, or that time I got
arrested for emptying a bunch of jello packets into Brian
Kranston's gas tank. It's it's a long story, but it
doesn't take a scientist to notice that adults don't generally
remember things that happened before the age of about three

(00:46):
or four. Why is that, well, why can't we remember
the earliest events in our lives up to an including birth? Okay,
here's an experiment. Try to remember what happened the last
time you ate a burrito? Where were you, who was
with you? Was the burrito full of spiders? These kind
of memories, being able to recall details of a particular

(01:06):
event in the past, are called episodic memories. A person
at age sixty will usually have some episodic memories from
age thirty. She might not get all the details right,
but she will be able to recall some events and
explain what happened. But if you take that same person
at age thirty and ask her to describe something that
happened to her during her first year of life, you'll

(01:28):
typically get nothing at all. Sigmund Freud referred to this
whole in our memory as childhood amnesia or infantile amnesia.
Freud being Freud, explained it by saying we needed to
repress memories from infancy because of their inappropriate or traumatic
sexual content. But sometimes a blank is just a blank,

(01:48):
and contemporary scientists don't tend to throw in with Freud
on this one. Another hypothesis that used to be popular
says that babies can't form episodic memories until they develop
certain cognitive of capacities, like language. But there's a major
problem with the language based hypothesis. Experiments have shown that
animals like mice also display both long term memory and

(02:11):
infantile amnesia. Since childhood amnesia acrosses species lines, it's probably
something to do with brain biology rather than language. One
possible answer would be to say that baby brains simply
can't make memories. It's true that memory encoding isn't as
efficient in infant brains as it is in the brains
of older children or adults, possibly because the prefrontal cortex

(02:36):
of a baby's brain hasn't reached maturity yet. But recent
studies have shown that very young children can form some memories,
leading scientists to think it's not that we don't make
memories early in life, but that after a certain point
we can't access them. The memories are made, but something
happens to them, they get erased or put behind some

(02:56):
kind of memory blockade. Patricia Bauer and Marina Larkina of
Emory University have led research on this hypothesis. For example,
in one study, researchers recorded children at age three describing
a recent event, like a trip to a theme park.
Years later, the researchers followed up with these same children
to see how much they remembered, and at ages five, six,

(03:19):
and seven, the children could recall more than sixty percent
of the earlier events, but by ages eight and nine,
their recall was less than More research of this kind
is needed, but this looks like watching the onset of
childhood amnesia as it happens. Another recent study has considered
the role of neurogenesis in the hippocampus. The hippocampus is

(03:41):
a part of the brain that's crucial for creating and
storing episodic memories. If you don't have either of your
hippocamp i, you could end up like that guy in Memento,
unable to make new episodic memories. Neuroscientists Sina Jocelyn and
Paul Franklin have proposed a theory that childhood and nisia
happens because of rapid formation of new cells in the

(04:04):
hippo campus when children are young. This is known as
hippocampal neurogenesis. Basically, while your brain is manufacturing lots of
the cells you will use to make memories for the
rest of your life, it wipes away or obscures the
memories you already created as a young child. Today's episode

(04:25):
was written by Joey McCormick and produced by Tyler Clang.
If you miss Christian, check out his current pop culture podcast,
super Context, and check out our online story at public
dot com slash brain Stuff. Every purchase supports brain Stuff directly,
and of course for more on this and lots of
other memorable topics, visit our home planet, how stuff works
dot com