Let's Talk Health

How to improve your memory (and why you forget in the first place) | with Prof. Matthew Mundy

• Torrens University Australia • Season 1 • Episode 1

Share episode

Tune in to our brand-new health podcast, where leading Health faculty members and researchers dive into the everyday factors that influence how we live, feel, and thrive.

Kicking off the series is Professor Matthew Mundy: cognitive neuroscientist, memory specialist, and Executive Dean of Health and Education at Torrens University Australia. We’ll unravel the mysteries of memory, explore what happens in the brain when information slips away, and ask whether it’s possible to sharpen our ability to remember.

In this episode, we cover:

  • The difference between short-term memory and long-term memory
  • How language development shapes memory in early life
  • Why teenagers and adults experience memory lapses differently
  • The role of attention, sensory input and multitasking in memory formation
  • How stress, sleep and distraction impact brain function and recall
  • Why memories are often inaccurate and how the brain uses shortcuts
  • Techniques for improving memory retention through chunking and repetition
  • Practical ways to strengthen memory and keep your brain active as you age

Connect with us and follow our news and stories:
→ Blog and Newsroom: https://www.torrens.edu.au/stories
→ TikTok: https://www.tiktok.com/@torrensuni
→ LinkedIn: https://www.linkedin.com/school/torrens-university-australia/
→ Facebook: https://www.facebook.com/TorrensUni/
→ Instagram: https://www.instagram.com/torrensuni

Natalie Cook:

Welcome to Let's Talk Health. I'm your host, Natalie Cook, Director of Innovation, Industry and Employability in Health and Education at Torrens University Australia. On this podcast, you'll hear from experts who'll share their knowledge to help you make more informed choices about your health. This week we're diving into something that affects us all, our memory. Why is it that we can recall a childhood phone number but forget why we walked into a room? How can we be so sure we said something only to realise later we really didn't? Our memory shapes how we move through the world, but it doesn't always get it right. So what's really going on in the brain when we forget? And can we even perhaps train ourselves to remember? To unpack all of this, I'm joined today by Professor Matthew Mundy, cognitive neuroscientist, memory expert, and the Executive Dean of Health and Education at Torrens University Australia. Thanks for joining me, Matt.

Matthew Mundy:

Wonderful to be here. Thank you, Nat.

Natalie Cook:

One thing, we've worked together for a while, disclaimer, we've worked together for a while, and one thing I know about you is you have a remarkable memory. Is that something that you've always just that is that how you're made, or is that something that's come about through your research?

Matthew Mundy:

That's a really interesting point because I think that there are people in my life that would tell you I have a terrible memory. Um I won't point any fingers there, but I think memory is complex, right? And I think it's possible to have great memory for some stuff and terrible memories for other stuff, and it's about what you prioritise. And I suppose when I'm at work, I am trying to remember the things that are really important in order to do what we do. And I think putting that cognitive effort into it is one thing. Um, but then when some elements, yes, we're sort of naturally better at in the same way as we're naturally better at all kinds of things, naturally worse at some other things. Um memory is definitely one of those things that some people are just not um uh as great at internalising things as others. That's not to say they couldn't be better with a bit of training and a bit of further understanding.

Natalie Cook:

This might sound like a bit of a basic question, but what actually even is memory? I've got in my mind a vision of Inside Out, the movie, and little baubles of memories, but what actually happens?

Matthew Mundy:

Well, there's two versions of memory when we're talking about how our brain retains information, which is the basic kind of description of what memory is. It's retaining information for future use, whether it's remembering something that might be useful to you in the future or improving something that might be better used in the future, it's about improving how we interact with the world around us, essentially. We can do that mindfully, we can do it consciously, or we can do it subconsciously. And so memory people talk about something called declarative memory and non-declarative memory. And when we're talking about declarative memory, we're talking about memories we're aware of. The sort of that's what people think of when we think of memories. What we have for breakfast, where we went on holiday last year, um, what the capital of France is called. We tend to think less of the non-declarative memories, and those are more like the habits and the skills. Like we know we learned to play the piano, that's a t hing we know we do, but we don't think about how we're playing the piano when we play the piano. It's a non-conscious memory, so it's kind of helpful to think about memory in those two terms sometimes.

Natalie Cook:

Interesting, and I think well, in lay terms, people will often talk about sort of short-term memory, long-term memory. Is that a thing? Like, is there a difference between the way we remember things more immediately than in the past?

Matthew Mundy:

It absolutely is, and I think we love to categorise memories, right, in memory science. And so in declarative memory, there are two areas one is long-term memory, the other is short-term memory. And they're both memories we're aware we have, but in terms of short-term memories, those are obviously the sorts of things that we're only needing to recall for a short period of time. The clue is in the name, and it's actually a completely different brain architecture that does short-term memory compared with the one that does long-term memory. So short-term memory comes about because you're the neurons that are trying to do the remembering for you are firing, they're active. Whereas long-term memory is about how our neurons change their connections. So they wire up differently in order to hardwire a long-term memory, whereas a short-term memory is all about how your neurons are firing in the moment, which is why short-term memory is really susceptible because if something stops your neurons firing for a moment, you'll forget. Whereas long-term memory is more robust because it's built into the structure of your brain.

Natalie Cook:

Wow, okay. So that's literally you do make memories. There's something physical going on because it's true, it's right. I know I do know childhood friends' phone numbers, and I do not know my closest friends' mobile numbers now. Is it because you're not thinking about it?

Matthew Mundy:

Yeah, that's right. That's so these days all our phone numbers are programmed into the phone for us. Its memory is our memory, and so you know, the only memory you need to know is how to access your phone and find your friend's name, and there it is. Whereas obviously back in the day when you have to dial the number, it made perfect sense for you to then recall the number itself and hardwire that into your your brain's long-term memory systems. Um, and that hardwiring is really persistent, it will last a lifetime. And so, you know, that number that you spent so long remembering because it was the only way you could get in touch with your friend, it's still there because the neurons that used to allow you to do that, they're still there too.

Natalie Cook:

And is that why as people age, often, and particularly I guess when they do enter into some more cognitive decline, that they might remember how to play the piano that they learned when they were a child, but they don't recognise someone immediate to them.

Matthew Mundy:

And partially that is because some of these memories are just in different parts of the brain, and the brain ages differently depending on the area of the brain that we're talking about. And it tends to be those more habitual memories, the non-declarative memories I was talking about, that are much deeper in the brain. They're in the older evolutionary term as part of the brain that is much harder to change over time, therefore they're more persistent. So those sort of procedural memories do tend to survive longer than what we call the more episodic long-term memories that relate to things that happened. Those are more susceptible to neural loss as the brain ages, you're on to die, connections with them are weakened or things happen within the brain to prevent transmission of data between neurons. As that increases over time, those connections that have been built into long-term memory become weaker, and so the memory itself becomes weaker, and then eventually it's possible to forget it.

Natalie Cook:

I'm thinking about different life stages, so that's where we've spoken about people later in life and what's happening in there. Are there other stages of life cycles where memory changes? And I'm thinking about teenagers, but that doesn't have to be your answer, but I'm curious, is it different?

Matthew Mundy:

Yes, there's some really significant parts of development where memory can make have very significant changes. The first biggest one is the development of language, bizarrely. So when a child learns to speak and learns words and learns to be able to articulate themselves, there is a sudden change in the memory abilities of that toddler. And it's because language helps us encode our memories, it gives us uh a way of thinking, a structure, something to then hook ideas and past events and expectations of future events and things and names for things. It all becomes part of a coherent system where pre-language, none of that organisation is there, and so the memory just is very fuzzy. So people tend not to remember things from before they had language. That's the first one. Then going to school and learning further language and organisation and knowledge structures, being able to then attach further learning to further structure and further organization, your brain's almost like a library, it loves structures and it loves organisation and it loves being able to bring memories and attach them to older memories and create stronger structures. So the more you learn, the more you have to attach things to, and so that that process of learning is another step change, and then yes, it it's a more declining period after that when as as you age your brain ages and some of those structures start to break down.

Natalie Cook:

So when people might complain, I don't know, they ask their teen to do something, they're like, Did you do that? Oh I forgot, or where's your bag? I don't know. You know, what's is that memory, or is that just being they're not trying?

Matthew Mundy:

It's actually both in many respects. So one of the prerequisites to remembering something is usually paying attention to it first. Right? Um and the way we get stuff into our memories is almost entirely through our senses. So vision being the primary one, auditory being the secondary one, and so to create the richest memory possible, you you engage as many senses as possible and it creates an amazing memory. But if you're not really paying attention, you're not really engaging any one of those senses in any particular strong manner, and so you actually stand a lower likelihood of remembering the thing that you're being told. And I think one of the things that happens in those circumstances is that team has just got a whole bunch of other stuff they're thinking about, you know, who they're texting tomorrow and what's happening in the in class, and you know what what's their favourite pop star doing. I don't know. There's other stuff going on, which means that attention is not necessarily on that thing they're being told to do.

Natalie Cook:

Okay, good. That explains that. Are there other factors? I'm thinking of, I don't know, you're about to stand up and give a speech and you can't, you know, the words aren't there, or you're at a a bank machine and you just can't think of your pin at the time you need to. Like what other factors can impact memory?

Matthew Mundy:

So many, and I think that's part of the problem. It's hard to pinpoint any specific one at any specific time, but there's it's often a blend. The the biggest one, the one that can impact kind of holistically across your day, would be how well you slept the previous night. Really? Sleep has a really strong impact on all many cognitive functions, memory being one of them. So if we don't get a good night's sleep, actually the the architecture of your brain isn't functioning in the way it perhaps could be, and therefore you're more aligned key potentially to be forgetting things. Stress is another really, really strong one. So if you're stressed out about something, the chemicals in your brain that are responding to that stress actually block memory transition in some respects. So we know that you know both chronically and acutely stressed individuals is slightly different pathways depending on where the stress is coming from, but it can impact your memory. So if you're stressed out, that could just be the reason you're not remembering that. And the other thing that's probably most often the case in those instances where uh you forget your pin or there's there's just too much going on and you can't quite pin down what it is that you're trying to say at the time, distraction is a big thing, and the reason distraction is a big thing, our memory, particularly short-term memory, because it's limited in its capacity, the more things we have going on at any one time, the more things are asking of your short-term memory. And if we're asking too much of our short-term memory at a given time, things will fall out. We'll forget things. There's a rule of thumb uh which many scientists argue about in this space, but I think it's a good illustrative example. Our short-term memory is roughly between six and eight items long. So if we have more than that number of things that we're thinking about any given time, we don't forget one another.

Natalie Cook:

Huh. So multitasking that is flawed.

Matthew Mundy:

It's flawed, that's right. It's it's limited.

Natalie Cook:

Some of the examples are quite superficial and quite well, it doesn't matter, you know, I couldn't think of someone's name or bit at the moment or something. Some of the impacts of forgetting are really tragic. And I know that some of your work has you involved in understanding why that happens. Uh you know, the stories you see in the news, someone has forgotten their child is in a car. What is actually happening? Because I think people see that news and go, oh, you can't, how could you? You know?

Matthew Mundy:

And I think that's the biggest hurdle with cases like that is as a parent, it's almost impossible to conceive of a situation where you could forget your own child. There's no way in which someone would sit down and think that is possible. But I think that the important point is in the moment, in your brain, and in the neurons that are firing or not firing as the case may be. It's not your child that's been forgotten. It's one of those seven or eight things on your mind that you have to do in the moment. Item on your to-do list was I must remember to take my child out of the back of the car and put them in daycare or whatever the case may be. It was just an item on a to-do list, it wasn't in your brain in that moment your child. And all of these things that can impact your short-term memory can affect a parent in that moment. And for example, you know, many parents are sleep deprived, particularly if they've got a very young child, they're already in a position where their short-term memory is at risk. So articulating that to a parent and saying, you know you forget things on a regular basis at the moment. When was the last time you forgot to pick up your mobile phone or you know you got yourself out of the house because you forgot to pick up your keys? Oh well, that happens all the time. But in your brain, in that moment, neurally, it's no different. It's the same issue whether you forget forget to pick up your keys is the same as whether you're forgetting to bring your child to daycare in that moment. So your brain doesn't make that adjudication, unfortunately.

Natalie Cook:

Interesting. What we think it's hard to conceive, but I think as you said, you know, our brains are built to do a job and they do that job and they don't discriminate necessarily or yeah. This notion of multitasking, we've said before, there's sort of six or seven things that our brains can do. I can vividly remember my grandmother knitting, and I swear she could have a conversation with you while she was knitting. She could probably have whipped up a baked dinner, I don't know what else she could have done. It was like part of her was operating quite independently from the other part. So she's having a conversation about nothing to do with what her hands are doing. What's happening there?

Matthew Mundy:

That's more to do with what we call executive function. Okay so within the brain we've got capacity to do things from a visual perspective, capacity to do things, let's say, from an auditory perspective, and the the brain's sort of resources to run those two areas are quite separate. So if you're doing something that's visually oriented, you can also pay attention to something that's sort of more auditory. But if you're doing something that's visually oriented, you're not so good at paying attention to something else that's visually oriented because that resource is already taken up. So if your multitasking involves different inputs like that, it's possible to then start adding in more things at once. You'll rapidly reach an endpoint, but that could be one way in which a task like that that's primarily I guess in terms of a habitual memory of how to work the knitting and uh potentially a visual task in in watching what you're doing, having a separate conversation about that is actually using a different part of the brain to those two things.

Natalie Cook:

Can you develop your memory? Can you learn to have a better memory? Are there's plenty of apps that'll pop up that saying you can? Can you?

Matthew Mundy:

That's a tricky one. In first principles terms, no, you're kind of stuck with what you've got, but you can trick it. And I think that's where a lot of these things work quite well. Short-term memory in particular, so you've got that limit of I don't know, but people argue six, seven, eight items, let's say. It depends how you're defining each of those items. So, for example, if you need to remember a phone number, then eight digits might be enough for you to get the rest of that number. That's taken up all eight spots in your short-term memory, that's it, you can't remember anything else.

Natalie Cook:

Yeah.

Matthew Mundy:

But what we naturally do, we don't remember all eight digits, we break them up. And it might be we remember two blocks of four digits. That's only now taking up two blocks in our short-term memory, rather than eight blocks. So the more we can learn to chunk down, the better our memories seem to become. And you can do the same with the shopping lists by creating chunks of things that naturally go together, you're reducing the capacity, or you're increasing rather the capacity of your short-term memory by making things go together. But there's some tricks you need to then play with yourself to try and develop that skill. And those apps are often playing on how you develop the skill what we call chunking that allows those those things to work together.

Natalie Cook:

And it feels like some I don't know, you see someone that tries to teach you how to learn a deck of cards or something, like it's a neat party trick. Seems impossible, but it's not remembering the cards per se, is it?

Matthew Mundy:

No, and it's remembering how to remember them efficiently. So, you know, someone that goes on stage and remembers every card in the correct order in a deck of cards, or lists of things that hundreds of items lock, they can tell you what was item 175 straight off the bat. It's because they've engaged in a very focused memory exercise in order to do that. Their short-term memory is still only six, seven, eight items locked. It's just that they've figured out how to cram more things into each of those items.

Natalie Cook:

Are there ways in a practical day-to-day basis that you can, if you're like, oh my god, my memory's terrible? What to pick is there any, you know, I know we said, you know, can you train it, but if you can't train it and you can't change it, how do you work with what you've got?

Matthew Mundy:

I think that that's the thing. So the biggest thing you can do is sleep well. Good sleep is the key to particularly improving your long-term memory. I was talking about those connections between neurons that form to hardwire memories. Sleep is when those connections are strengthened the most. So the more and better quality sleep we can get, the stronger that consolidation of memory becomes overnight as we're sleeping, the stronger the long-term memory is in the long term. Students go through periods of revision before they go and do an exam. The reason revision is so such a strong technique for remembering stuff, your brain works best when it's exposed to things multiple pi multiple times over a period of time. And so when we're thinking about teaching topics, we don't just teach something once and then never, never, never again. It's integrated into a sort of a scaffolded approach to learning. By revisiting topics, you're sort of going back to the brain and re-strengthening some of those connections, reinforcing how that piece of information fits with the stuff you already know. And so being able to revisit information goes to strengthening those connections once more. And so that process of revisiting information across time and waiting a little while after you've learned something to then come back to it, and then that's a really strong way of improving that long-term memory piece, and then otherwise it's very hard to say don't get stressed, but you know, relaxation, mindfulness will reduce the impacts of those sorts of things on memory as well. And nutrition is important to memory. Um, eating well and ensuring your brain has the appropriate resources to do the things it needs to do, poor nutrition impacts memory, and so making sure that you have a good intake of the appropriate nutrients.

Natalie Cook:

That's fascinating. Last question given all of that, we're aging from the day we're born, but we've got an aging population, and obviously memory often comes up as something that you know is compromised as we get older. Is there anything we can do to age our brain strongly?

Matthew Mundy:

I think the biggest thing with aging is activity, both physical activity and cognitive activity. So people talk a lot about ensuring you maintain physical activity as you age in order to maintain a healthy body. Exactly the same principle when it comes to your brain. So the more you can exercise your brain cognitively, I think the stronger then lack of progression there may well be in that aging process. And so that's where some of those apps around brain training and you know, it used to be doing the crossword or sudoku, they're all valuable things to do, even though they feel like you know whiling away time. It is in fact exercising the cognitive parts of your brain and keeping them active in a in a positive manner that then reinforces the connections between the neurons that I've been as I was talking about, rather than letting them just uh be and have that potential of then uh fading away. There's a phrase we use and it's it's it's called use it or lose it. Right. And so using it is definitely positive.

Natalie Cook:

We've covered so much today, really super interesting, really, really interesting. I think the trick will be remembering some of the tips and the tools and and taking them into daily life because it's such a practical conversation and such an insight to understand what's actually going on in something we just do or not do without even thinking about it. So thanks, Matt. Thank you. Pleasure. And a disclaimer the information discussed in this podcast is for general information purposes only and is not intended as medical advice. The content should not be relied on as a substitute for professional health care, and if you have any concerns about your health, please do consult a qualified healthcare professional.

Head Shot

Natalie Cook

Host