WEBVTT - Why Can't People Remember Being Born?

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<v Speaker 1>Welcome to brain Stuff from How Stuff Works. Hey, I'm

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<v Speaker 1>Christian Sager, and welcome to brain stuff. A lot of

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<v Speaker 1>things are easy to remember. My high school graduation, for instance,

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<v Speaker 1>or my first summer job, or that time I got

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<v Speaker 1>arrested for emptying a bunch of jello packets into Brian

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<v Speaker 1>Kranston's gas tank. It's it's a long story, but it

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<v Speaker 1>doesn't take a scientist to notice that adults don't generally

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<v Speaker 1>remember things that happened before the age of about three

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<v Speaker 1>or four. Why is that, well, why can't we remember

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<v Speaker 1>the earliest events in our lives up to an including birth. Okay,

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<v Speaker 1>here's an experiment. Try to remember what happened the last

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<v Speaker 1>time you ate a burrito? Where were you? Who was

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<v Speaker 1>with you? Was the burrito full of spiders? These kind

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<v Speaker 1>of memories, being able to recall details of a particular

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<v Speaker 1>event in the past, are called episodic memories. A person

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<v Speaker 1>at age sixty will usually have some episode memories from

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<v Speaker 1>age thirty. She might not get all the details right,

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<v Speaker 1>but she will be able to recall some events and

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<v Speaker 1>explain what happened. But if you take that same person

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<v Speaker 1>at age thirty and ask her to describe something that

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<v Speaker 1>happened to her during her first year of life. You'll

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<v Speaker 1>typically get nothing at all. Sigmund Freud referred to this

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<v Speaker 1>whole in our memory as childhood amnesia or infantile amnesia.

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<v Speaker 1>Freud being Freud explained it by saying we needed to

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<v Speaker 1>repress memories from infancy because of their inappropriate or traumatic

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<v Speaker 1>sexual content. But sometimes a blank is just a blank,

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<v Speaker 1>and contemporary scientists don't tend to throw in with Freud

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<v Speaker 1>on this one. Another hypothesis that used to be popular

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<v Speaker 1>says that babies can't form episodic memories until they develop

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<v Speaker 1>certain cognitive capacities, like language. But there's a major problem

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<v Speaker 1>with the language based hypothesis. Experiments have shown that animals

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<v Speaker 1>like mice also display both long term memory and infantile amnesia.

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<v Speaker 1>Since childhood amnesia across his species lines, it is probably

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<v Speaker 1>something to do with brain biology rather than language. One

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<v Speaker 1>possible answer would be to say that baby brains simply

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<v Speaker 1>can't make memories. It's true that memory and coding isn't

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<v Speaker 1>as efficient in infant brains as it is in the

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<v Speaker 1>brains of older children or adults, possibly because the prefrontal

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<v Speaker 1>cortex of a baby's brain hasn't reached maturity yet, but

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<v Speaker 1>recent studies have shown that very young children can form

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<v Speaker 1>some memories, leading scientists to think it's not that we

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<v Speaker 1>don't make memories early in life, but that after a

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<v Speaker 1>certain point we can't access them. The memories are made,

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<v Speaker 1>but something happens to them they get erased or put

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<v Speaker 1>behind some kind of memory blockade. Patricia Bauer and Marina

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<v Speaker 1>Larkina of Emory University have led research on this hypothesis.

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<v Speaker 1>For example, in one study, researchers recorded children at age

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<v Speaker 1>three describing a recent event, like a trip to a

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<v Speaker 1>theme park. Years later, the researchers followed up with these

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<v Speaker 1>same children to see how much they remembered, and at

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<v Speaker 1>ages five, six, and seven, the children could recall more

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<v Speaker 1>than sixty of the earlier events, but by ages eight

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<v Speaker 1>and nine, their recall was less than More research of

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<v Speaker 1>this kind is needed, but this looks like watching the

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<v Speaker 1>onset of childhood amnesia as it happens. Another recent study

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<v Speaker 1>has considered the role of neurogenesis in the hippocampus. The

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<v Speaker 1>hippocampus is a part of the brain that's crucial for

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<v Speaker 1>creating and storing episodic memories. If you don't have either

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<v Speaker 1>of your hippocampy, you could end up like that guy

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<v Speaker 1>in Memento, unable to make new episodic memories. Neuroscientists Shina

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<v Speaker 1>Jocelyn and Paul Franklin have proposed a theory that childhood

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<v Speaker 1>amnesia happens because of rapid formation of new cells in

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<v Speaker 1>the hippocampus when children are young. This is known as

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<v Speaker 1>hippocampal neurogenesis. Basically, while your brain is manufacturing lots of

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<v Speaker 1>the cells you will use to make memories for the

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<v Speaker 1>rest of your life, it wipes away or obscures the

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<v Speaker 1>memories you already created as a young child. Check out

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<v Speaker 1>the brainstuff channel on YouTube, and for more on this

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<v Speaker 1>and thousands of other topics, visit how stuff works dot com.