Jane: This is But Why: A Podcast for Curious Kids, from Vermont
Public. I'm Jane Lindholm. On this show, we take questions
from curious kids all over the world, and we find answers. Have
you ever...Have you ever...shoot, I forgot what I
was gonna say! Good thing today's show is all about
memory. We're going to talk with someone who can help us
understand why we forget things and how we remember.
Nick Turke-Brown: I study how the brain works and the magical
things it does that help you learn and remember and make
decisions and get along with your siblings and be creative,
make art or music, have ideas and go about and grow into, you
know, adults.
Jane: That's Nick Turke-Brown. He's a professor of psychology
at Yale University. Psychology is the study of how we think and
behave and how our minds work. Professor Turke-Brown was
excited to hear what kinds of questions you've sent us about
memory. So let's get right to them.
Brynn: Hello, I'm Brynn. I'm 11 years old, and I live in New
Katie, Texas. How does memory work?
Logan: Hi, I'm Logan. I'm six years old. I'm from [unclear].
How do humans remember stuff?
Zeph: My name is Zeph, I'm six years old, and I live in Austin,
Texas, and my question is, how do we remember things?
Clara: I'm Clara and I'm five years old. I live in Oak Park,
Illinois. How do you remember something?
Noah: My name is Noah, and I'm three years old. I live in
Sunnyvale, California. How do brains remember things?
Nick Turke-Brown: Memory is basically your brain keeping a
record of things that you experience. So when you see
something or you hear something, or you go somewhere, that
changes your brain, and your brain is able to then hold on to
that experience and carry it forward in time until you get
reminded of something, or you see something again, or you go
back to the same place, and you're transported back to the
last time you saw that thing, or you were in that place. And so
basically it has to do with the effect of seeing or hearing or
doing something on what's in your brain. And so your brain is
like a recording device. You could think of it like a phone
or a camera, but it's happening all the time without you trying.
And it's really amazing how well it works. So that's essentially
what's storing memories, is that when you have experiences, your
brain changes.
Jane: The really cool thing about that is there are
different parts of the brain that store different things and
help you form different types of memories.
Nick Turke-Brown: Some parts of your brain remember when you
learn how to ride a bike, you know that experience of falling
off and then getting going and pedaling and moving fast, and
that part of memory, you could think of it, what we might call
motor memory, or how to do things, is supported by some
parts of the brain. But there are other kinds of memories,
too. You have preferences, like you like macaroni and cheese, or
you like pizza. Those are preferences, things that you
find rewarding or valuable. There are other parts of the
brain that store those kinds of memories. When you eat something
that you really like, or when you do an activity that you
really enjoy. Then we have other kinds of memories that are, I
think of as maybe what people normally refer to as memory, is
like remembering a specific event. So I might remember going
on a vacation or my last birthday party, or when I got
grounded, or when I got my first, you know, tablet, or when
I had some very memorable experience visiting a
grandparent, those those events in our life, that's a different
kind of memory, and that's supported by another part of the
brain. And so that's kind of the answer is your brain is
influenced by what you experience. Different parts of
the brain are storing different parts of the experience.
Jane: Not only are different parts of the brain involved in
recording and saving those different types of thoughts or
experiences, but there are a couple different stages when it
comes to remembering them. The first one is that initial stage
of thinking or feeling or experiencing something and kind
of recording it in your brain.
Nick Turke-Brown: That's what we call encoding. It's like the
storage of the memory, but to make it stick, your brain sort
of chews on it a little bit. It has to keep processing that
information, and that's what happens during sleep. You think
of dreaming as a kind of chewing on your memories, and what that
does is it makes them more stable. It helps them stick
around longer. So that's the second part. So you initially,
you store the memory, or encode the memory, and then you
consolidate the memory during sleep, and then the final part
is retrieval. You have your next birthday party and you remember
the last one, or you go to a place that you haven't been in a
while and you remember that, or you remember some piece of
information that somebody told you, or you remember how to do
something, and you're accessing something that's been stored and
consolidated in your brain. So that's what I would say what
memory is, it's changes in your brain, different parts of your
brain, and there's these different stages of encoding,
consolidation and retrieval.
Jane: You know, it's interesting. You mentioned
something like our preferences, the things we like and dislike.
And I hadn't thought of that as memory, but of course, it's tied
to your experiences in the past. So something like, if you really
like cheesecake, but then one time you have cheesecake, and
then the next day you get the flu and you throw up the
cheesecake, you're gonna remember that and you're gonna
not like cheesecake anymore, even though maybe those two
things actually didn't have anything to do with each other.
Your brain makes an association, and that can change your
preferences, which is, of course, tied to your experiences
and memory.
Nick Turke-Brown: Yeah, that's there's a name for that. It's
called the Garcia Effect. So it might have been the cheesecake
that made you feel sick, but because the cheesecake occurred
before you got sick, it gets associated with that feeling of
sickness, and then you afterwards, you might not be
attracted to it as much, or like it as much, or you might want to
avoid it. And so, yeah, that's a kind of memory. It's very fast
memory. That only has to happen once, and then for the rest of
your life, you might not like cheesecake anymore.
Jane: What a bummer.
Nick Turke-Brown: Yeah.
Jane: Yeah, and then those ideas like learning how to ride a bike
and remembering how to do it, or when you have something that you
have to learn in science class and you're going to have a test
about it and so you have to remember it. And often, we're
told, if you're studying to learn something for a class, the
best thing you can do is get a good night's sleep before your
test. So that's what you're talking about, Nick, with the
idea that your brain needs to get all of that stored in the
right place so that you can pull it out when you need to retrieve
it, or when you need to know that fact. So sleep really is
important for learning and memory.
Nick Turke-Brown: Definitely. People remember better, and they
not only remember the details of what they learned before after
sleep, but you're also able to use that experience in new ways,
what's called generalization, taking something you learned
before and applying it in a new setting. We do that in school
all the time. You learn some concept about biology, and then
you have to apply it in a new way, or you learn how to use a
certain trick in math class, and now you have to use that to
answer a new question that you haven't thought about before. So
that ability to take memories and use them in new ways, that
is the specific benefit of sleep, and you can see why
that'd be really important for a test.
Jane: We got a lot of kids who want to know why they can't
remember things from when they were really little.
Sage: Hi, my name is Sage. I'm eight years old. I live in Los
Angeles, California. Why do we forget things that happened when
we were babies?
Lola: Hi, my name is Lola. I'm eight years old. I live in Palos
Heights, Illinois. Why can't you remember stuff from when you
were little?
Iris: Hi, my name is Iris. I am nine years old, and I live in
Melbourne, Australia. Why can't we remember when we were little?
Julius: Hi, my name is Julius. I am seven, eight years old. I
live in Ottawa, Ontario, Canada. Why do people forget things from
when they're little?
Natalie: Hi, my name is Natalie. I'm eight years old, and I live
in netherford, New Jersey. Why can't we remember when we were
babies?
Archer and Maddie: My name is Archer, and I'm seven years old.
And my name is Maddie, and I'm 10 years old. We live in
Melbourne, Australia. Why can't we remember things from when
we're little?
Nick Turke-Brown: Yeah, this is what's known as infantile
amnesia. So amnesia is a fancy word that means forgetting.
Infantile means from the time that you were an infant or a
baby. Generally, as older kids and adults, we don't remember
much from the first few years of our lives. Usually, if you ask
somebody, what's your first memory, if they're old enough,
they'll they'll generally say, you know, somewhere between four
and seven years old. Now, if you're a five year old, you
might remember something from when you were two or three, but
by the time you're seven or eight or nine, that's going to
be gone. So why? It's a deep scientific mystery. It's one of
the topics that my lab at Yale University works on. We study
what's happening in the brains of babies and toddlers as
they're forming memories. And so we're trying to figure out why
it is that we don't remember what happened during that time.
Now, I think it's important to say it's not just that time
passes and we forget things. So it's not just that, you know,
that was a long time ago when you were a baby and so of
course, you forget it. Because later on in life, you're going
to remember things from a long time ago, you know, from when
you're 10 years old or 20 years old, but there's a specific time
when you're sort of zero to four years old where you don't
remember very much. So we're talking before about how there's
different stages of memory, like there's the encoding, the
storage part of the memory, there's the consolidation, and
then there's the retrieval, like accessing the memory. And so
each of those stages is a possible point at which you
might have a failure, when you're really young, and be
unable to kind of access those memories. So is it that babies
don't store memories, so there's nothing to retrieve later on
because you didn't store a memory in the first place? Or do
they store them fine, but later in life, we just can't access
them for some reason, we can't retrieve them? And so our
research suggests that starting around 12 months, so around one
year old, babies are able to start storing memories in their
brain. And this is much earlier than people's first memories, so
it suggests that there are memories being stored by around
one year of age, and we lose access to them later on. And so
we're trying to figure out why is it that we can't access those
memories? And there's the there's the sort of science
fiction possibility that we still have those memories in our
brain from when we were babies, and we just can't get back to
them using the normal way. And so maybe there are, you know,
tricks we could use to remember things from earlier in our life.
Jane: You know, if you spend time with a very young kid, if
maybe you have a little sibling who's one or two, you might be
aware that they seem to have really great memories, because
you might have a two year old brother or sister who every time
they pass one street, they just say "Bird!" because you saw a
goose there once, and you would forget that there was a goose
there one time, because it either wasn't a very important
moment, or you've got a lot of other things you're trying to
remember, but that toddler remembers that one little
detail. It sometimes seems like toddlers have really great
memories.
Nick Turke-Brown: Yeah, I think that's right. That's part of the
reason we started studying this. How is it that as adults, we
don't remember anything for that period, and yet, young kids
often have, like, pretty good memories?They remember a person
that they met, or a magician they saw at the at the park, or
a song that they love, or they remember that after this turn in
the road you get to their daycare, or you remember some
little toy you know that they got on Halloween. So I think
that infants and toddlers have memory, and for whatever reason,
those memories don't stick around, and they might still be
there and just inaccessible, or they might get lost with the
passage of time, but that's what we're working on. It's
definitely true that kids, especially babies and toddlers,
are learning a tremendous amount. We talked about learning
how to ride a bike or developing food preferences. That's all
happening in the first couple years of life. If you think
about learning language, every baby who's brought up in a home
where they hear a language learns that language without
really trying, and actually, they learn it much better than
an adult or an older kid can learn that language. We're
really, really good at learning early in life. We learn how to
walk. We learn about relationships with siblings and
with parents. We learn about food. We learn about our home
environment. We learn the names of objects. So infancy is an
incredible period of learning, and that makes it even more
mysterious why we don't remember anything from that time.
Bennett: I am Bennett. I live in Sammamish, Washington, and I
want to know how and why do brains forget.
Mac: My name is Mac. I'm six. I'm from Indianapolis. Why do we
forget?
Clara: Hello. My name is Clara. I am six years old. I am from
Superior, Colorado, and my question is why do people forget
things?
Nick Turke-Brown: Forgetting is sometimes frustrating, like
you're trying to find a toy or you're trying to remember
somebody's name, but a lot of the time, forgetting is not such
a bad thing. Memory is limited, and forgetting helps clean up
our memories. So when you try to remember something, it might be
hard to access it, and that's because a lot of other memories
are coming to mind. You might be trying to remember one thing and
you're remembering other unrelated things, and that's
called interference. So part of the reason we forget things is
because other unrelated memories are coming to mind and
distracting us or confusing us. So forgetting is a way of, kind
of cleaning up memory and removing or reducing
interference. And we think of forgetting as bad, but I want to
emphasize that some forgetting is good, and it makes your
overall memory better. It makes it better able to remember the
most important things.
Jane: So forgetting isn't all bad news, but it can also be so
inconvenient when it happens.
Ella: Hi. My name is Ella. I am seven years old. I'm from
Bannockburn in New Zealand, and I would like to know why do we
forget what we are going to say while we are waiting for our
turn to speak?
Nick Turke-Brown: Yeah, so I think there's a lot of the kinds
of memory we've been talking about: remembering a birthday
party or how to ride a bike, or facts that you learn in class, I
would call those with long term memory, memories that stick
around a long time. There's another kind of memory, called
short term memory, which refers to holding on to information in
our mind for a short period of time. So if you're in class and
you're waiting to ask a question, you might have thought
about this question. You're waiting your turn, and you have
your hand up, and you're holding that question in your mind, and
then you get called on and you can't remember what you wanted
to say. That's a failure of short term memory. And what
happens in short term memory is that in order to keep that
memory alive, you have to actively think about it; you
have to focus on it. And so anything that happens that might
distract your attention--somebody else asking
a question that you think is interesting, or, you know, I
don't know, a siren that passes on the street, or maybe some
other question that comes to mind in response to what
somebody else is talking about, that could distract you. And
when you get distracted, you lose your grip on that short
term memory that you had in mind. So in that situation, it's
probably about distraction. Those kinds of short term
memories also just get weaker over time. So if you're
rehearsing something in your mind, you're holding on to some
information, the longer you have to do that, the more likely you
are to forget it.
Jane: We were talking earlier about how important sleep is to
memory, but Claire is wondering,
Claire: Why do we not remember things we say in the middle of
the night when we say we want to remember them in the morning?
Jane: And is it the same thing if, let's say you fall asleep in
the car, and your adult wakes you up to go to your bed, and
you say something, and then the next morning, they say, do you
remember that silly thing you said when I was carrying you
back to your bed? And you're like, No, I don't remember that!
Same type of thing?
Nick Turke-Brown: Yeah, it's probably similar. If you're less
awake, it's very hard to pay attention when you're dozing
off. So it might be you're also just not storing memories very
well at that point.
Jane: It's fascinating to think about how our brains are hard at
work while we're both awake and while we're asleep, even though
we're not necessarily aware of all that work our brains are
doing to consolidate, store, retrieve and even remove
memories. After the break: why are some people forgetful, and
do elephants really never forget?
BREAK: BREAK
Jane: This is But Why! I'm Jane Lindholm, and today we're
learning about how our brains remember things with Professor
Nick Turke-Brown of Yale University.
Ava: Hello. My name is Ava. I'm nine years old. I'm from
Peterborough, England. Why are some people forgetful?
Nick Turke-Brown: Yeah, you know, some people have better
memories. Some people have worse memories. Even within what you
would expect of healthy you know, typical kids and adults,
there are people who are more forgetful than others. There's
even people who have really amazing memories, you know,
better memories than everybody else in general. But all of this
is pretty normal, like even people who you would think of as
forgetful, are still healthy and remember what they need to
remember to do well. There are people who have worse memories
because of medical conditions, like if they have something
called mild cognitive impairment or dementia, or you might have
heard of Alzheimer's disease. These are medical conditions
that make memory much worse, where you forget loved ones,
even. But within the healthy kind of typically developing
population, there's variation, but it's all pretty normal and
to be expected. And again, remembering more is not always
better. What you would want to remember is the important
things, not everything.
Tyce: Hi, I'm Tice. I am nine years old. I live in Bluffdale,
Utah. Why do we forget things? And what does our brain do with
the things we forget?
Nick Turke-Brown: Well, there's lots of different reasons you
can forget. Like, the memories can be sort of erased. How
memories are stored in the brain is through cells in the brain
called neurons. These are like cells in the rest of your body,
but neurons are cells in your brain, and they they connect
with one another. They touch each other. And how they connect
with one another is how memories are stored. Those are called
synapses. Those are how two cells talk to each other, and
the pattern of how cells are connected to each other is how
memories are stored. This is different from our computer
stores, you know, a file or a photo, but our brains store
memory is that way. And so if you lose those connections,
either the cells themselves die, sometimes over time, or you lose
some of the connections break down, or the brain region grows
or changes in its composition, those memories can essentially
get get erased so that they're gone. That's one kind of change
that happens in the brain. That was one of the theories of
infantile amnesia that we were talking about before, is that as
you get older, and that sort of three to four year old range,
you have a lot of new cells in your parts your brain that store
memories, and they might be overwriting memories that you
already have in there. That's called neurogenesis, like the
birth of new neurons. So that's one kind of erasing.
Another kind of forgetting that happens in the brain is when
there's a disconnect between how the memory is stored and then
how you access it. So you might have some cells that are
connected in the brain through synapses in a certain way that
stores a memory. But if, when you see a familiar person or you
go to a familiar place, it doesn't get matched to that
memory, you're not going to be able to call it to mind and
retrieve it and remember that earlier experience. So it's not
that the memory itself is gone, it's that you can't get it. It's
like if you have a book and you can't find your book, right, you
know you have the book you might look on your bookshelf and you
just can't find it. So you can't read what's inside it. It's that
kind of an issue. The book still exists. It's just under your bed
or somewhere else. You just can't get to it. And so that's
another reason why we forget a change that happens in the brain
is that the cues, the things in the world that remind us of
things, just don't map onto or can't be used to access the
memory. And for example, when you meet somebody you know at
the park or at school, you don't just remember that person's face
or their name. You link that person to the place that they're
in. So you remember that you met this kid on the playground, and
if you see that same friend at the grocery store, you might not
even recognize them, because that's not where you saw them
the first time. So memories are stored in what's called a
context, in a place, in a situation. And so a lot of
forgetting occurs because we're not in the right context. You go
to the grocery store, you're not expecting to see a friend that
you just met on the playground, and so it's harder to recognize
them. And so a lot of forgetting happens when we're just not in
the right mindset in order to access a memory.
Jane: We have just a couple more questions. One is from Poppy,
who wonders...
Poppy: Why, when you bump your head hard on something hard, you
lose your memory?
Nick Turke-Brown: Yeah. Hopefully Poppy's not bumping
their head a lot like this, because it's, it's usually not a
great sign if you have an accident, or you fall off your
bike, or you fall down on the playground and you bump your
head and you can't remember something, you definitely should
tell a parent or and maybe go see a doctor. That can be a sign
of a concussion or sometimes called a traumatic brain injury,
TBI. So that's not a common thing, hopefully, to bump your
head in a way that would make you forget. But it is the case
that when people get in accidents like a car accident or
a bicycle accident, or fall on a playground, that can cause
either temporary or longer lasting damage to the brain. It
could be that in the moment, you know you're playing with your
friends, and you fall and then you can't remember what you were
just doing a moment ago. That could be because you maybe you
lose consciousness, or maybe you're in a lot of pain, and you
sort of forget what you were doing. So that that would be a
less scary version of this. But if you had a more significant
accident that caused brain damage, that can cause damage to
parts of your brain that are really important for memory, and
so it's not unusual in cases of bad accidents like that, to
damage some of the parts of the brain that are important for
memory, or some of the connections in the brain that
help you to take a memory and then act on it. So I would think
of that as, hopefully, a rare event, but it is a real
consequence of accidents that people have problems with
memory.
Annika: My name is Annika, and I'm five years old, and I live
in Chicago, Illinois. How do grownups remember everything?
Nick Turke-Brown: Well, the good news for Annika is that grown
ups do not remember everything.
Jane: I can say that's true.
Nick Turke-Brown: I can say that as a grown up, but it sometimes
feels like that when you're talking with your parents,
they're like, know it alls or have all the they have all the
answers when you ask them a question.
Jane: Or they remember, I told you to clean your room
yesterday.
Nick Turke-Brown: They remember some deal they made with you.
But the answer is that grown ups don't remember everything.
Adults and kids, we store some memories, but not everything. It
is also the case so that adults have more experiences. So if you
think of what we were talking about before as memory being
about, you have some experience, you're doing something, and your
brain is plastic. It's like Play Doh, it's being molded based on
your experience. Adults just have more of that. You know,
they've gone through school, they might have a job, they have
a family, they have some skills, they have a lot of
responsibilities. So they've gained knowledge over time, and
they can use that knowledge to answer questions or even to
store memories better. The more you know about the world, the
easier it is to store memories, because you're taking things you
already know and recombining them in new ways. So it is the
case that adults have more knowledge. That's a kind of
memory. It's often called semantic memory, memory for
facts or details. That is something that increases over
your lifespan as you have more and more experiences, as you
spend longer in school, and as you you know, learn new things.
So adults do have more of that, but I wouldn't say that they
remember all of the events or experiences that they've had in
life any better than than an older child would.
Eva: My name is Eva. I am eight years old. I live in Dayton,
Ohio, and my question is, how do elephants remember everything?
Nick Turke-Brown: Yeah, it's really interesting. You know,
elephants have good social memories for other elephants.
They have good memories for navigation routes. So they kind
of move a lot through their through their environment, and
they can remember different locations in their environment
well. They have an interesting social group dynamics, and so
they remember about how other elephants are behaving. And so
they do have good memories, but I don't think they're
exceptional. Most large animals and even a lot of small animals
have great memories. It's really important to survive in the
natural world, to learn from trial and error, to learn from
experience, to learn what's safe and what's not safe, or who's
kind and who's unkind. Evolution has endowed our brains with the
ability to store memories, and that's true of almost all
species. In animals like mammals, we have brains that are
really evolved, that have certain parts of the brain, like
a region called the hippocampus. It's like a hippopotamus, but
hippo-campus. And that brain region is in mice, in elephants,
in humans, and it stores memories in all of those
animals. So animals vary a lot in what kinds of things they
remember. You know, mice might remember how things smell. Dogs
might remember how things smell better than humans. Elephants
might remember large environments better because they
move a lot. So there are different kinds of knowledge or
memories that different animals need in order to survive and
thrive in their niche, and humans have that too. So
elephants, there's kind of the sense that elephants have great
memories. They do have large brains. They do have some of
these brain structures that are really important for memory are
large in elephants, and so they probably do have great memories,
but so do so do sea lions, so do humans, so do mice, and without
that, we wouldn't be able to learn from our mistakes. We
wouldn't be able to make predictions about what's going
to happen in a new scenario. We wouldn't be able to build
relationships with other animals or humans. So memory is really
the core of who we are, and without memory, you lose a bit
of your own identity, your own personality.
Jane: And don't forget your brain is storing memories all
the time, not just when you're trying really hard to memorize
something. That includes right now. What do you think you're
going to remember from this episode? Thanks to Dr Nick
Turke-Brown of Yale University for helping us understand how we
remember and how we forget things. He has his own lab where
he studies memory. As always, if you have a question about
anything, have an adult record, you asking it on a smartphone
using an app like Voice Memos. Then have your adult email the
file to questions@butwhykids.org. But
Why is produced by Sarah Baik, Melody Bodette and me, Jane
Lindholm, at Vermont Public and distributed by PRX. Our video
producer is Joey Palumbo, and our theme music is by Luke
Reynolds, if you like our show, please have your adults help you
give us a thumbs up or a review on whatever podcast platform you
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We'll be back in two weeks with an all new episode. Until then,
stay curious!