Do animals care about the past?

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1:09What is this noise, Oles? It's OK. You're listening to CrowdScience from the BBC World Service, the show that answers your science questions. I'm Caroline Steele, and that yowling sound is my cat, Ollie. He's just spotted his number one enemy. A white cat that sometimes likes to hang out in our garden. How dare he? It's okay, it's just a cat. Looks like you'd do with a snack. Let's not his. Let's be nice. Shall we try being nice? Ollie never fails to recognise his rival or to react with ear-splitting howls. He seems to remember this cat and their beef with each other every time they cross paths.

1:56I'm pondering my cat's memory thanks to a question from one of our listeners. I am Dr. Taiwo Olani from Morgon, Osmo State, Nigeria, but I currently live in Portsmouth in the UK. So what's your question for CrowdScience? My question to CrowdScience is, do animals care about their past? And what made you think of this question? First, I've been listening to programmes by Sir David Attenborough, of course. I used to interact with these programmes a lot. then recently I came across a textbook on the history of the English language and in the textbook it was said that the interest in the past is what distinguishes animals from a human and I was like oh can I send it to craft science and see what evidence they are going to get from it.

2:51Okay right well I like this we've got a specific line in a textbook to fact check and also you mentioned David Attenborough there so do you mean sort of you've watched Blue Planet and Planet Earth and peered into these unbelievable worlds and you're wondering you know what's going on? Yeah I have. And what do you think? Do you think like the textbook that you read that an interest in the past separates humans from other animals? I wouldn't say yes because I think that is up to cross hands to let me find out. OK, I like that. We'll talk to the experts and find you an answer. What separates humans from animals is an interest in the past.

3:36That's a 900-year-old quote from Henry of Huntington, an English writer. Now, to me, it feels a bit outdated and quite a bold claim to make nowadays. And this Nataiwo is also wondering if it still holds true, according to modern science. To understand if animals are interested in the past we first need to look at how animals understand the past which brings us to Cambridge University in the UK home to some baby magpies who are in an indoor enclosure and to be honest aren't too thrilled to see a new unfamiliar face. So they're really, really young. They're super young, yeah. They're gorgeous. They're not even two-monthers yet.

4:19This is Professor Nicola Clayton. She studies cognition in corvids, a highly intelligent group of birds that includes crows, ravens, rooks, jackdaws, jays and magpies. They're beautiful. I mean, they're sort of mostly black with a white chest. Oh, and don't forget the gorgeous green ultraviolet sheen. Ah, OK. Oh, you've heard a few peeps. Hello. If you catch the magpies in the right light, Their black tail and wing feathers appear a beautiful deep green colour. What research have you done, I guess not with these specific birds, but with this species? Well, they're a bit young for us to have done too much yet, but we're looking like psychologists do with young babies in how cognition develops.

5:09How does thinking emerge? When do they start to know things? When do they start to make inferences? when do they start to put things together? And does that include researching and understanding their memories and the way they form memories? Oh, absolutely. So one of the first things that we've started doing with them is asking if and when they develop object permanence. Object permanence is the understanding that objects that we've come across continue to exist, even when we can no longer see them, hear them or otherwise sense them. Human infants first show signs of object permanence at about four months old.

5:51If you see me with my iPhone, you can see it now. Now you can't see it anymore. But because you have object permanence, you know that my iPhone continues to exist, even though you can't see it anymore. Now, if you know it continues to exist, you have to have a memory of where you saw it and where you think it now is. and even though you can't see it, you know where it is because you have a memory of where you saw me put it. Yes, I see what you mean. You know something exists regardless of whether or not you can see it. Well, that's what memory is, isn't it? A memory is something you saw and then disappeared but you know it continues to exist because it's still in your mind's eye.

6:41It's not how memory is normally described but it is a way of describing memory, right? So one way we can define memory is an understanding that something that you can no longer see still exists. But can you test for object permanence in birds? You can hide things in little pups and see whether they know if it's something they really like, something really valuable, like a yummy food item or a shiny object, that they'll come back and search for it. when they want it. If you hide a treat under a cup and a baby magpie still looks for it, even when they can't see it anymore, it demonstrates object permanence.

7:23And the real smarty pants is behind the scenes chess. She's checking us out. She's the really clever one. And she's already past stage four object permanence, which is the stage at which they show that they can understand that something continues to exist even though you can't see it. So she understands that when you leave this room, you're still alive out there living a life. I think so. And then you come back in and you're here again. You still exist in between your visits. Yeah. Object permanence is one of the earliest building blocks of cognition, and we see it in species across the animal kingdom.

8:02It's part of how animals, including us humans, make sense of the past and understand the world around us. But we're not just looking for evidence of memory. We want to know if animals are interested in the past. And for that, we're going to need to look inside our brains. Memory is supported by a network of brain regions. But let's say the critical node in this network is generally considered to be the hippocampus. So a brain region that lies deep inside the human brain. This is Freya Olafstotir. She's an assistant professor of neuroscience at the Donders Institute for Brain Behaviour and Cognition at Radboud University in the Netherlands.

8:43Okay, so the hippocampus is kind of the most important brain region in memory, human memories. You said it sort of involves lots of different regions. Which other parts of the brain are involved? So another region that's been studied quite extensively is the prefrontal cortex. So that's really the front part of the brain, particularly in humans. So that's a part of the human brain that's quite distinct from other animals, even other primates. So it's proportionally very big in humans. And so we need the frontal cortices to really allow us to very accurately recall memories. Okay, so the hippocampus is kind of acting a bit like the library and then the prefrontal cortex is the librarian going, okay, let's get that book.

9:29Exactly. That's, I think, a useful analogy in this context. Yeah. So the hippocampus is really critical for forming memories, right? And allowing us to remember single events like your last birthday or what you had for breakfast this morning. Sometimes it's called event memory or episodic memory is the more technical term. Episodic memories are memories of personal experiences in your life. What happened, where it happened and when it happened. And a small C-shaped structure tucked deep within our brains called the hippocampus plays a key role in forming these episodic memories. Whereas the cortex is thought to kind of contain what's called semantic memory.

10:09So that's more kind of knowledge, like knowing what the capital of France is. So we've got two key regions of the brain, hippocampus, prefrontal cortex. How does that compare in other animals? Do other species basically have the same brain set up when it comes to forming memories? Rats and mice have a hippocampus. Its anatomy is strikingly similar to the human hippocampus. Cats and dogs and bats also have a hippocampus. To an extent, even birds have a hippocampus. So it's something that's shared. It's converged. Evolution has kind of converged on this region. It's come up with the same hardware for memory, you could say.

10:53So if many animals have a hippocampus, does that mean many animals also have episodic memories? There is disagreement in the field about whether episodic memory is uniquely human. I've thought about this a fair bit, actually, and obviously I study rodents. I'm well aware of the similarities, the structural similarities between the rodent and the human hippocampus. But with time, the definition of episodic memory, which has its root in psychology, has evolved. And now, you know, you're meant to be able to show that the animal is also able to consciously recall a memory. Episodic memories could be key to answering listener Taiwo's question.

11:34They're the conscious recall of past experiences. And if animals can consciously revisit past experiences, then I'd argue they're showing an interest in the past, not just responding to it. My cat Ollie always meows at dinner time. But is he reminiscing about previous meals, or is he simply following a learned pattern that earns him a reward? So it's six o 'clock, it's dinner time, and my cat Ollie has come in from outside, and now he's being noisy. What is it you want? Have you noticed the time? Do you remember something?

12:13He's saying it's six o 'clock. Excuse me, have you not noticed? So he's walked me over to where his food is because he remembers where his food is. And he's like, excuse me, why aren't you feeding me?

12:26Here's your wet food, Oles.

12:30Oli knows that he gets dinner at around 6pm and if he meows at me persistently, he usually gets it a bit sooner. Is this an example of episodic memory? Even though that could be that they have a recollection of a past event when they are doing that, that behaviour doesn't necessarily show that they have this complex mental representation of a past event, right? This is Hema Martin-Ordas, a psychologist at Stirling University in the UK. She specialises in animal cognition, including memory. When we talk about remembering past events, we are actually going back in time mentally and we project ourselves into that past event and we have this picture of the past event, right?

13:17where I was having breakfast this morning, what I was having, what clothes was I wearing. You can do what your cat is doing without actually having that complex mental representation. So he could, will be remembering in the way that we're talking about, but that alone wouldn't be enough evidence to say that they can remember the past in the way that an episodic memory will allow them to do. We can't prove that Ollie is consciously recalling the past. We know he has a hippocampus. We know he's altering his behaviour based on past events. But does he have conscious episodic memories, memories of dinner's past?

13:58We can't be sure. So to me, the best example of episodic memory is based on a study that we did a while ago with great apes. And this task asked, in this case, it was chimpanzees and orangutans. if they could remember an event that happened three years ago. So three years earlier, we showed them a task in which there was a reward and they couldn't access that reward. And to do that, they had to use a tool. But I hid the tools, so they saw me hiding the tools and then we just gave them access to the rooms where the tools were hidden and they had to go and pick it up. The apes found the tools they needed to access the reward.

14:42But what's particularly remarkable is for how long they remembered where these tools were hidden. So three years later, what we did is we showed them the task, but we didn't show them where the tools were hidden. And what they did is once we gave them access to the rooms again where the tools were hidden, they went straight away to find the tools. Wow. It was from the very start of the trial, so it didn't take them long to find them. they were not wandering around the room, so they weren't strict to retrieve the tool. Three years later. I mean, I lose my tools that I've put down three minutes ago.

15:20The fact that three years later, they remember where to find a tool. It was really impressive, and it was really impressive to see because we didn't know what they were going to do, so this was the first time that something like this was tested. And to me, this is so far the strongest evidence that we have that great apes can remember past events. So that's an example of episodic memory? To me, it is. Yeah. But again, if we go back with the definition of episodic memory in which the conscious aspect is critical, then we still don't have evidence that this is exactly episodic memory following that definition.

16:00From a behavioral perspective, it is. There is only one possible way to solve that task, which is remembering that past event. To me, it feels hard to argue that great apes aren't consciously remembering coming across these tools in the past when they know exactly where to look for a tool three years later. But again, technically, we can't prove this recall is conscious. Although, is it enough to start nudging us towards an answer to listener Taiwo's question? If an animal can use a memory from three years ago to guide its behaviour today, Isn't that demonstrating some kind of interest in the past?

16:37I think that still is a little bit of a stretch. Again, it depends on how you will define the interest, right? I think there can be a basic level, which is I have an interest in that event because it's helping me to solve this problem. But that level of reflection on the past event, I don't think we have clear evidence yet of that. Hemmer's experiment with great apes is strong evidence of long-term memory that can be applied to something useful. But we can't say the apes are showing an interest in the past, as we can't prove that they're reflecting on what they remember. The same goes for rodents.

17:14They may have a similar brain structure to humans, but still no evidence of an interest in the past. But what about Nicola's corvids, famous for their incredible problem-solving? They may not show an interest in the past as infants, but maybe we can find evidence once their brains have fully developed. That's coming up.

17:59When you hear the phrase made in China, what do you think? I'm Tristan Redman. And I'm Asma Khalid. And together we host the Global Story podcast from the BBC. And today on our show, we look at the origins and evolution of made in China because it actually wasn't inevitable. What we're talking about is the world's largest communist nation is at the beating heart of the capitalist system. For more, listen to The Global Story on bbc.com or wherever you get your podcasts.

18:32Next.

18:37You're listening to CrowdScience from the BBC World Service, the show that probes the memories of scientists to find answers to your questions. Listener Taiwo got in touch wanting us to fact-check a quote he came across in a textbook. This is what he read. An interest in the past is what separates humans from other animals. I'm going to have one last try at proving that my very intelligent and very noisy cat Ollie cares about his previous experiences. OK, I've just arrived home from work and I'm really hoping that my cat Ollie is going to greet me with a meow or two. He only does this with people that he knows and recognises.

19:17Strangers who just sort of sits and silently watches. So let's see what we get. Hopefully he's in. Let's see.

19:27Hey, Oles. Hi, Ollie. Ollie, are you aware who I am? I think we have to take that as a yes. I think observations are the absolute cornerstone and starting point. But as a psychologist, you then need to do proper experiments. Yes, OK. so I need to do some research on Ollie. Here's our Covid expert Nicola Clayton again. I think you need a bit more hard work on it. I agree. I think as an inspiration for why this could be a relevant question, yes. But I think you have to figure out whether he's just reacting to a safe smell that's been learned over time or whether there's something he specifically remembers about you.

20:22Interesting. And that's the challenge. It's a challenge because what you have to do with any animal is to really get inside their heads and think what's appropriate to them. Yes. You have to do something that means that they're motivated. Okay, so I'm going to have to start ruling some things out. You might need to join our lab for a year or so and do an internship. Sign me up. Oh my gosh, an internship on cat memory. Can you imagine? A cat research project would be new territory for our COVID expert, Nicola. Keen CrowdScience listeners may remember we spoke to another COVID researcher in our episode Do Animals Have Funerals?

21:03where we heard how they appear to have memories of people who might be dangerous to them. Check it out wherever you get your BBC podcasts. Now, Nicola is currently studying the cognition of baby magpies. But what about her previous experiments with adult birds. She's studied scrub jays and what they do with their stores of food, or caches, when they're around other birds. What we showed is that birds who have been thieves in the past, if they're watched, then they're trying to hide their caches. When those others, that public audience, has left the scene, they move them to new hiding places. So they've used their past experience of being a thief to think, those thieves over there, they might like to steal those valuable caches, in the case of jays and worms.

21:53Jays who have a history of stealing and are being watched by other birds become very protective of their food. But naive birds who haven't thieved in the past don't do it. Interesting. So they're almost able to put themselves in the shoes of a thief because they have behaved in that way before. Precisely. Except then... The only problem with that is Jays don't wear shoes. But other than that, I think you just bought them. That's so interesting. Okay, so that is using a memory of the past and using it to plan for the future. I think that's hard to argue that that's not an interest in the past. I guess you could say, okay, we don't know that the birds are sort of consciously thinking, hmm, that happened, I should avoid this happening.

22:43But still. Absolutely. Absolutely, you're spot on. I think the problem is we can never deal with the thorny problem of phenomenological consciousness. Phenomenological consciousness is the subjective experience of being aware, essentially what it feels like to be you. I don't even know you're conscious and you don't even know that I'm conscious. True, I'm just sort of taking your word for it. We infer it through conversation, right? Now the thing about the J's though is that they're very flexible. So I said experienced thieves do this, naive ones don't. But if the experienced birds are hiding the food in front of their mate, with whom they're happy, under certain terms and conditions, to share their caches, just as in any marriage, under certain terms and conditions, they don't move them to new places.

23:35It's clear that Jay's memories help them make some remarkably sophisticated decisions, like deciding to hide food from other birds if they themselves have stolen before. But if the other bird is their partner, that's OK, they're allowed to steal food. But are Scrub J's consciously thinking about the past? It's only through language that we've come to understand human consciousness. So until we can communicate with animals, we simply can't answer that. Here's Freya again. She studies rodents. So I don't think there is anything that should rule out that they are conscious. animals. But they're strikingly intelligent animals.

24:15And actually, I find that the more I study animal behaviour and the brain of non-human animals, I find it harder and harder, actually, to differentiate humans. You know, to say, what is it different about being human? Yes. I mean, there are obvious differences, but they have remarkable ability for abstract cognition. It might well be that animals have conscious episodic memories, memories of events, but we can't prove it, which means we haven't yet answered listener Taiwo's question. Do animals have an interest in the past? But maybe there are other ways of showing interest. Here's Hema, our great ape expert again.

24:56I think if you can think of interest in the past as, well, I take that event to learn or to do something different in the present to not make that mistake again, then any evidence of learning will be considered evidence of reflecting in the past. and if you can consider that having an interest in the past is that I have to remember to do something so I know that I'm gonna get that reward that I really want then I think there is evidence of that in non-human animals. Have you done any research into that? Have you got any examples from your work? There is research on that in terms of using these past memories for planning for a future events.

25:45I've done a little bit of research on that with great apes and they can definitely take into account these past events to plan for future ones. So could you tell me a bit about that research? How did you test this? Chimpanzees were presented with tasks but there were no tools and then they were taken to a different room and there were some tools but there was no task. When taken into a room with only tools, the chimps were able to remember the tasks they'd seen earlier and identify exactly what they needed. So they were able to take the correct tool and they took it to their sleeping room and they kept it for 24 hours and then they brought it back into the testing room.