How Memory Works

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Brian Lehrer: Brian Lehrer on WNYC. One of the mysteries of life is our relationship with our memories. We think we remember things worse as we age, we associate loss of memory with disease, fairly or not. It's become an issue in politics now too, with questions about Trump's and Biden's memories. Did Trump really forget that Nancy Pelosi and Nikki Haley are not the same person as one of his campaign speeches seem to suggest?

Well, a new book by a University of California Psychology and Neuroscience professor suggests we may be thinking about our own memories in some of the wrong ways, and we might be happier with a little attitude adjustment toward what we remember and what we forget. The book is called Why We Remember: Unlocking Memory's Power to Hold on to What Matters by Charan Ranganath, who is a UC Davis professor of psychology and neuroscience . Professor Ranganath, thanks very much for coming on. Welcome to WNYC.

Charan Ranganath: Thank you. It was very exciting. I'm actually now jonesing for a WNYC hoodie or hat.

Brian Lehrer: Maybe we can work something out. Listeners, anything you've ever wanted to ask an expert on memory but never had one over for dinner, now is your chance. Text or give us a call at 212-433 WNYC, and that's obviously our on airline. We're never going to ask you for money on the air. 212-433-9692 if you have a question about memory. You write that instead of asking, "Why do we forget?" we should be asking, "Why do we remember?" I'll bite. Why do we remember?

Charan Ranganath: Well, memory is, at heart, about the present and the future. It's not about the past. As a result, our brains are extraordinarily economical in grabbing the most essential parts of our past so that we can carry it forward to understand what's happening now and to take it into the future. I think part of why we have these wrong expectations is because we think memory is supposed to be an effortless replay of the past entirely as it happened, and those are just not realistic expectations nor would we want to have a memory system like that.

Brian Lehrer: You write that we should try to remember better, not remember more. What's better, if not more when it comes to memory?

Charan Ranganath: That's the great question. What does it mean to have an optimal memory? If we were to carry around every piece of information we've ever encountered, it would be a massive amount of information and there would be gobs of redundancy, and we wouldn't be able to use it very efficiently. Imagine you're trying to carry around as much cargo as possible where you could create a container ship or you'd create a big truck. Effectively you'd be using tons of resources to move that thing around. You'd require a lot of energy, and it would be very hard to turn it around and move it quickly and make it agile because that vehicle is designed to carry a bunch of junk.

In fact, that's pretty much what ChatGPT is when it comes to memory. It's basically just loaded with a lot of junk. On the other hand, our brains are extraordinarily efficient, which allows us to access what we need when we need it. Sorry. No, go on. I'm losing track of the question.

Brian Lehrer: Well, you write that "Forgetting isn't a failure of memory. It's a consequence of processes that allow our brains to prioritize information that helps us navigate and make sense of the world." That's a quote from your book. What does that mean? Unpack that for us.

Charan Ranganath: Well, just take the simplest example. I'm, right now, actually in a cafe on the fifth floor in London, and I've never been to this place before. If I go back to my hotel room and I wake up in the middle of the night, I've got insomnia, which is happening because I've got jet lag, I wake up at 3:00 in the morning, my first thought is, "Where am I? This is an unfamiliar room. I've been here less than 48 hours." I have to ground myself in space and time by saying, "Oh, yes. I actually checked into this hotel yesterday. I was completely jet-lagged, and then I had to go to all these meetings."

By doing a little quick moment of mental time travel and retracing my steps, I now know where I am in the present moment. Now take into account another example like you're watching a movie. At any given moment, some character comes in, but really to make sense of what's happening in the moment, you need to call back on all of these other things that happen.

If you're watching a horror movie, for instance, and you see a character just walking down a hallway, you're probably not paying attention to that character walking down the hallway, you're thinking about the fact that in the past they had left the group. In the horror movie, the person who leaves the group is most likely to be killed. [chuckles] You're thinking, "Where's this person going? Why did they do this?" You're thinking about the person you can't see which is the chainsaw-wielding maniac who's in the kitchen, and you're wondering, "Is this person going to get killed or not?"

You're using memory to generate this rich model that's not what's in front of you, but it's really the meaning of what's in front of you. It's really saying to yourself, "How did this person get here, and where's this person going?" It's this thread that connects to the past, the present, and the future.

Brian Lehrer: That connects to another interesting concept in your book, which, I guess, is fairly self-evident, and that is that multitasking impairs memory. I want to ask you about another thing that I found fascinating and many listeners probably will. You say that memory updating is at the heart of psychotherapy. Memory updating is at the heart of psychotherapy. What do you mean by memory updating?

Charan Ranganath: Sorry about that. I had a little glitch with my microphone. Are you still there?

Brian Lehrer: It's okay. You're back.

Charan Ranganath: Okay, good. Sorry about that. What I mean by that is-- geez. Hello? Sorry. Are you there? Do you hear me?

Brian Lehrer: We hear you. We do hear you.

Charan Ranganath: Okay, good. Sorry about this. I think intuitively we tend to think of memory as this playback of the past. If you play a movie from your computer, every time you play it it's exactly the same. The thing is that when we remember things, we're actually not replaying the past. We're actually both playing and recording at the same time. That is, every time we recall a memory, we actually change that memory itself. If you have a memory that you call back, many, many times, you've updated that memory. Sometimes people update that memory based on their beliefs that are based on shame or based on guilt or something like that.

These memories are loaded with all of this heavy baggage basically. In psychotherapy, I really learned this, and this was one of the things that really led me into my scientific career in memory research, is that when I would be working with patients, what patients really wanted was to share these painful memories that they hadn't shared before. Once they would open up that memory to me it was an act of updating the memory, because first of all, just to explain it, you have to shape it into some story that makes sense to someone else. Then me as an outsider, I'm reacting to and reflecting on this memory, and I'm integrating it into a story that's not from their perspective.

I think this is a hugely important thing, is that we view the past through a particular perspective, but we're capable of changing it, we're capable of updating, and often these perspectives that we get locked into or what keep us in a bad place. Getting an outside perspective can lead you to update the memory and see your past from a different way, say from something shameful that you experienced to being a survivor who's resilient.

Brian Lehrer: My guess, if you're just joining us, is Charan Ranganath, UC Davis professor of psychology and neuroscience . His new book is called Why We Remember: Unlocking Memory's Power to Hold on to What Matters. Ron in Manhattan, you're on WNYC. Hi, Ron.

Ron: Hi. My question is, what is a mental block? I'm a writer and I can write a piece. As I'm writing, I don't remember a certain person's name, and then the next time I try to remember it, I can't remember it, and then the next time I can't remember it. The question is, what is a mental block? Does it get worse as one ages? I'm in my 60s.

Charan Ranganath: This is a great question, and it happens to me all the time. [chuckles] In particular, it happens to me more when I'm sleep-deprived or if I'm stressed out. I don't know if this is you too. It definitely happens more as you get older. What's going on is that essentially memory is not something that essentially you just pull up one memory and it's all good. You actually have an ecosystem of memories that are fighting against each other.

Sometimes what happens is that if we pick the wrong thing by accident, so in other words, if you pull up the wrong name, now you're in trouble because that wrong name becomes very active in memory, and it starts competing with and suppressing the memory that you're trying to find. As a result, what happens is you can get blocked and you can get stuck, or another thing might be you're just in the wrong mindset, and you're not thinking about it in just the right way, because essentially, you have to have a queue in memory that's like the key that unlocks the door to that memory.

Those things often can be unlocked later on when you're in a different mindset and you're away, and you don't need that information anymore. Normally, you'd rely on a brain area called the prefrontal cortex to be able to suppress the stuff that you no longer need to help you generate a good search strategy, and so forth. As we get older, the prefrontal cortex becomes a little more inefficient. As a result, it takes us longer to pull up what we need.

Brian Lehrer: You can work on it, according to your book. One thing you say is you can sharpen your memory skills using a process known as chunking and you cite memory athletes like Scott Hagwood and Yänjaa Wintersoul using that process called chunking. My first question about that is, there's such a thing as a memory athlete?

Charan Ranganath: Yes. This actually is a tradition, in some ways, that goes back to the older carnivals and things where people would do a memorization show, and you'll still see these [unintelligible 00:11:20] around even now. You could probably hire one for one of your birthday parties [chuckles] or something. It's been adapted and evolved into these competitions, where people will get an entire deck of cards, and they'll test people on their ability to memorize these cards. They'll get 200 names and faces, and they have to memorize all of these names in 20 minutes or something.

These are extraordinary features. One of them, I believe her name is pronounced Yänjaa Wintersoul. She was a memory athlete and decided to memorize an entire IKEA catalog.

These people are doing these extraordinary feats, and yet, if you ever hear any of these memory athletes talk, they'll all tell you that they're not actually extraordinary people in the sense of being born with some magical memory ability. They just use strategies like chunking, which is using your knowledge and using things that you know very well as a way of organizing information and reducing the amount that you have to memorize.

A memory athlete doesn't memorize more, they just memorize less, and they utilize more of what they had before.

Brian Lehrer: That's chunking, breaking it into chunks?

Charan Ranganath: That's exactly right.

Brian Lehrer: Maria in Central Jersey, you're on WNYC. Hi, Maria.

Maria: Hi. My question, I'm really interested in the part that relates to therapy and people's memories because I have a very distinct childhood memory. Many years later, I'm now in my 60s, I discussed this event with my sister, who lived through it with me. I took away guilt from this experience I lived with my whole life, and my sister took away something totally opposite and nothing to do with us being guilty for something.

It was just so incredible to me. I actually was able to let go of that memory and that feeling a little bit because of it, because I had remembered it one way and she remembered it another way, and I trusted her memory of it. I've also been in the other situation with a family member where you tell a story and they have a take on it that you're like, "No, that is not how it happened, and I don't remember it that way," and you feel threatened by their way of remembering it. What explains that? How do you deal with that?

Charan Ranganath: One of the fascinating things about memory is when we remember an event, we remember it based on our current beliefs and our current situation. As a result, sometimes what happens is people come to believe certain things about their past and then that gives them a perspective that allows them to build a story in a certain way. As a result, what happens is that if you and a sibling, for instance, like your sister, if you have different beliefs about where you're at in life now and you have different beliefs about how your childhood transpired, that will give you a different way of reconstructing the story.

One of the things I say in the book is that memory is much more like a painting than a photograph where a good deal of a painting is some of a painting, some people might be very photorealistic with their paintings, and some artists may be very abstract and impressionistic. There's always some degree of detail and then there's some degree of distortions of whatever it is that the subject is, and then there's a lot of inferences and interpretations that just reflect this person's perspective.

As a result, two people can experience the exact same things and come to very different conclusions. This is why people who are in two different political parties might watch a debate and walk away remembering completely different sound bites of what the candidate said based on their own political preferences too.

Brian Lehrer: It's so interesting. I was just having a conversation like that with my mother about why I didn't go to a certain high school. Was it because she didn't want me to go, or was it because I didn't want to go? We'll never really know the answer. We're both coming as people of good faith in that memory conversation, but we remember it exactly the opposite. That certainly happens in families.

Let me give you one more. We have a minute left, and here's a question from a listener that turns the whole thing on its head. Listener asks, "If there are ways that people try to improve what they remember, can we also work on things we want to forget?" Whoa. There've been Star Trek episodes about that, where people have traumatic episodes and then somebody figures out how to wave their magic wand from another planet, and they forget the traumatic memory. Have you ever been asked that before, to improve your ability to forget things?

Charan Ranganath: Yes, actually. One of the things that people ask me a lot about memory is trauma because those are the memories that often stick with us. Our brains are designed to carry with us the things that are most biologically important and traumas are part of that. They elicit emotions like fear and sadness and so forth. These are the things that really are often biologically important events, but in our human world, they can actually just get hijacked by things that we don't want to carry with us.

I'm actually doing a panel discussion tonight for the movie Eternal Sunshine for the Spotless Mind. The whole premise for this movie is that these people try to hire a company to erase their memories for particular experiences.

There's definitely a school of thought and there's researchers like Mike Anderson in Cambridge who have developed a technique where they basically tell people-- they try to cue a memory to get it to come alive, but then they tell people to suppress it over and over and over.

Brian Lehrer: We have 15 seconds.

Charan Ranganath: Oh, sorry. That technique can, in fact, reduce people's memory for those things. I would argue that you don't want to forget the traumatic experiences, but you want to change your relationship with it and reframe and change your perspectives.

Brian Lehrer: Charan Ranganath, UC Davis professor of psychology and neuroscience and also runs what they call the Dynamic Memory Lab out there at the University of California at Davis. He's now author of the book Why We Remember: Unlocking Memory's Power to Hold On to What Matters.

Thank you so much. This was fascinating, and I could tell from our caller board texts that listeners really appreciated a lot of the information.

Charan Ranganath: Thank you for having me.

 

 

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