The Current - Babies can store memories, new study suggests

Episode Date: March 21, 2025

A new study suggests that babies as young as a year old can store memories. One of the study’s authors explains why humans don’t remember being a baby despite that newfound fact, and what questions remain about our earliest memories.

In the complex world we are living in, today's boards must be resilient by design. Join the Institute of Corporate Directors on June 3rd and 4th at the Edmonton Convention Center for the National Director Conference and Fellowship Awards Gala. Network with Canada's largest director community and learn how to be more resilient in the face of increased demands on the board. Register at conference.icd.ca slash join. Institute of Corporate Directors. Think beyond the boardroom.

This is a CBC podcast. Hello, I'm Matt Galloway and this is the current podcast. In an episode of the kids TV show Peppa Pig, the title character comes face to face with a surprising reality courtesy of her friend Susie. And that reality is that Peppa used to be a baby once. Mummy Pig is working on the computer. Mummy!

Hello Peppa. Susie is talking nonsense. No I'm not. She said in the olden days I was a baby. Well you were Peppa. Look, here are some photos on the computer. Who do you think that is? It's Baby Alexander.

Baby Alexander is Peppa's cousin. No, that's you as a baby, Peppa. Baby Peppa. Peppa, of course, does not really remember being a baby pig and we humans don't really remember being baby humans either. This is a phenomenon called infantile amnesia. We are unable to recall events and experiences that happened to us before about the age of three or four. Now, new research in the journal science is getting us closer to understanding why this

actually happens. Nicholas Turk Brown is a psychology professor, director of Yale University's Wutsi Institute. He's the senior author on this study. Nick, good morning. Good morning, Matt. This is so interesting because people like to believe that they can remember things before they were three or four years old. But tell us what's going on here. How common is this that we don't actually remember the things that happened to us before that age? You know, there's patients out in the world who have damage to their brain

and they can't store new memories, and these are exceptionally rare cases. We've studied some of these folks in my lab, but every human being on earth, billions of people walking around are amnesiac for this period of infancy. And we might think that we remember this time, but in fact, those are mostly stories we've heard or pictures we've seen as you just heard in that clip.

Pete That somebody kind of feeds that memory to us or we feed it to ourselves, but it's not actually something that we remember. Pete Indeed. Pete Tell me more about this concept of infantile amnesia. What is that? This is a really old mystery. Why is it that we have this blank spot in our personal history? And there's been various ideas about this. For example, maybe the brain just isn't mature enough to be able to store memories.

Or maybe they're getting in, but later in life we just can't access them. And so that's what our study was trying to figure out. is that we're not storing the memories in the first place, or are they there perhaps, but not accessible? This is this idea of the brain encoding memories, right? That's right. Encoding just means your brain, a particular brain region we're studying here is called the hippocampus,

taking a snapshot of the current experience that you're having. Do we know how early that begins? I mean, that's at the heart of this research. When do we start to encode those memories? So that's what we're looking at in this study based on what adults report. Traditionally, it was thought around four or five years old. In fact, what we found in this study is that beginning around one year of age, this brain

region called the hippocampus is able to form memories. I wanna come back to that and what those memories might be, but how do you go about studying this? I mean, there had been some experiments with mice, but how do you test this in babies? Yeah, it's a really, it's a passion project in my lab over the last decade to try to figure out how to do this. Most of the tools that you can use to study a baby's brain

involve putting sensors on their head, but these tools don't really get deep in the brain where the hippocampus is located. And so what we did is we took the techniques that we use with adults, it's a version of MRI called functional MRI that's able to find brain activity all over the brain, and we had to figure out how to do functional

MRI in babies. In some ways, they're the worst possible study participants for an MRI to work. You have to be completely still, even one millimeter, and yet babies are wiggly. Imagine taking a- Good luck with that. Yeah. I mean, it's like taking a photograph in low light. If you move at all, it gets blurry.

So we had to develop methods to keep them still. We use a lot of little tricks, getting parents involved in the research, giving the baby a bottle or a pacifier, making sure they're comfortable and happy, and that we're showing them something that they think is really interesting. Tell me more, part of this is about what you're looking for

when the babies are actually able to be still in that MRI? What specifically are you hunting for? Yeah, this is a very simple experiment. We show the babies photographs of, it could be a person's face or a dog toy or a waterfall, and then after some amount of time, maybe a minute or so, we show them that photograph again, paired with a new photograph they haven't seen before, another face, for example, and we measure where they look. You can't ask a baby, what do you remember? They can't speak. And so we use their eyes as a window into their memory,

and they tend to look more at a picture if they remember seeing it. And then the brain activity, what do you see when they actually seem to remember something? Yeah, so we use what they look at to figure out which of the photographs they're remembering, and then we look back at when they first saw that photograph, what was going on in their brain

when they saw something that they later remembered versus something that they later forgot, and what we found is that the hippocampus is more active, it's more engaged in encoding the photographs that they later remember beginning around one year. So tell me more about that. If the hippocampus is more active in that moment when they see something that they've seen before,

what's going on? Yeah, so it's when they see it for the very first time, the idea is that the hippocampus is taking a snapshot of what they're seeing. And when that happens, then when they see that photograph later on, again, after other things and after a delay, then they look at it more when the hippocampus is active.

So it tells us that they, we were sort of observing the formation of the memory in the hippocampus at that time that predicted what they later remembered. And so that would suggest that the memory of the thing that they have seen has been encoded somewhere, that there is a snapshot has been created. Indeed.

This happens as early as 12 months old, you're saying? Yeah, we didn't know when this was gonna happen. So we studied babies from four to 24 months. And overall, this was true. But if we drill into the data, the effects are much clearer beginning around one year. Is it fair to call it a memory? I mean, memory is such a slippery term in some ways.

Is it fair to call that a memory? Oh, yeah, so memory means many things, and there are many different kinds of memories. So this is a particular kind of memory called an episodic memory. It's a memory for something that has just happened once, what you had for dinner last night, where you went on your last vacation,

some particularly memorable event in your life. You just experience that once and you can store it rapidly in one go. So that's one kind of memory, but there are other kinds of memories as well. Learning language, that doesn't happen in one go. You pick up on patterns of the sounds you hear as a baby over months and years. Other kinds of memory have to

do with how you move your body, learning to ride a bicycle. You can't really describe that memory, but you know how to do it. And so we're looking here at the idea of episodic memory, memory for specific events. And this is what people often refer to colloquially as memory when you're being nostalgic for something that happened in your life. So if you pull back a little bit, what are some of the things that would be collected from 12 months on?

Some of that information that would be coded in 12 months on? Yeah, I mean, it's hard to know. This is a frontier now. We didn't know this was possible, and so now we're doing research to try to understand the characteristics of this baby memory. Instead of showing photographs, we're now having parents

record home videos of what their baby's experienced at home. You know, it could be going to the playground or meeting a grandparent or going on a trip. And so we have the ground truth. We know what the baby's experiencing in their real life and now we can bring them to the lab, use functional MRI, show them videos from their own life versus from another kid's life

and see what kinds of content get encoded in memory and how long those memories last. If those memories are there, it goes back to what we were talking about earlier, why can't we access them? If those things have been imprinted somewhere, why can't we get to them? Yeah, it's a really interesting question. It's something we're working on. Here's an idea. Here's our current sort of speculative theory. Imagine you're a baby, say a 12-month-old baby, and you go visit your grandparent.

You're lying on your back. You can't walk yet. Maybe you're looking at the ceiling. You're hearing chatter around you. You're hearing sounds, but you can't make sense of the language. You're seeing objects, but you don't really know what they are. But you're at your grandparent's house. Then let's say, and you store memory of that.

Let's hypothesize. Then you go back there when you're a five-year-old or a 25-year-old. Maybe it's the same house, the same people, maybe the same topics of conversation, but now you are different. The way you're experiencing that environment is very different.

You are walking around, so you have a different vantage point, you're making sense of the conversation, you recognize the objects and the concepts that are around you. And so the way that your brain is experiencing that repeated place is different. What the hippocampus does when it forms memories, it takes a snapshot of how the brain is experiencing the world at that moment.

So when you do that as a baby and then you go back to that same place as an older kid or an adult, that input to the hippocampus has now changed dramatically and you might not be able to look up the memory that's there because the input is wrong. It's like if you enter the wrong term into a search engine, for example. You have said that there's a sci-fi element to this where those memories might endure,

but they're still inaccessible. And that the sci-fi part of this is we can figure out some way to get back to those early memories. What's tantalizing to you about that? Well, I think it's just a deep scientific curiosity about why we have this gap in our autobiography and it's fascinating to think about whether those really early experiences linger in us.

This is something that's been tested in mice, where you can go in and directly stimulate the memory in the hippocampus in an adult mouse and show that they can retrieve a baby experience. We can't do that in humans, but maybe there are tricks we can use to bypass these issues of why memories aren't accessible and pull up fragments of our early life experiences. I mean, parents think about this a lot

because we think about what are the experiences that we can create that will stick with our kids. And there's this whole concept of core memories. I wanna play you something, this is from the movie Inside Out, which kind of put this idea of core memories into the public consciousness. Have a listen to this.

These are Riley's memories, and they're mostly happy, you'll notice, not to brag. But the really important ones are over here. I don't want to get too technical, but these are called core memories. Each one came from a super important time in Riley's life, Like when she first scored a goal, that was so amazing. So if you go on social media, you'll see parents orchestrating these elaborate kind of experiences for their kids and they say, we're creating a core memory.

This is something that we are going to create that will be coded into our children forever. Is that a thing? Can we actually influence what children remember about their childhoods? I mean, what a wonderful idea of trying to make your child's life memorable. I'm skeptical that parents have that kind of power to control what

kids remember ultimately, but it's certainly the case that creating a home environment, creating experiences that lead to a rich, fulfilling life is a wonderful thing to do. The implication in that clip is that those memories define the kid's identity, their personality. That's the link that's not really proven that you could have a really memorable trip or score a goal, and then that would define who you are. I think that's a bit of an open question. And certainly the ability to shape a kid's memory

really only would start in terms of being accessible around five or six years old. What is the question you still want answered? I mean, I'm sure you have a lot, but what is the big burning question you still want answered when it comes to children and memories? Yeah, this study demonstrates that the baby's hippocampus has the capacity to store memories around 12 months. There are many open questions.

How long do they last? We only tested a few minutes in this case because we had them in the MRI machine. So we're doing longitudinal studies now where we follow families for years and hopefully for many years where we know what they experienced as a baby, like the Peppa clip where they saw a picture from that time. But we know what that is and we can measure the persistence and the durability of those memories over time to see whether it's really true that they last into childhood and possibly beyond. This is so interesting.

Nick, it's great to talk to you about this. Thank you. Thanks so much for your interest. Nicholas Turk Brown is a psychology professor and director of Yale University's Wu Tsai Institute.