Dogs and the humans who cherish them have a unique bond unlike any other. We wonder all too often, do our dogs love us as much as we love them? What are they really thinking? Are we projecting our own feelings onto these treasured family members in trying to understand them? Emory University neuroscientist Dr. Gregory Berns, has made some extraordinary findings. After spending years using MRI imaging technology to study the human brain, he then used this same approach to study dogs’ brains. It turns out that our furry friends are much smarter than we thought!
Dr. Philip Stieg: Do dogs really love us, or just care about food toys and shelter? How do we know what a dog is feeling? What do they understand about us and how can we better communicate with them? To answer these and many other questions about humankind's best friend is my guest neuroscientist, Dr. Greg Berns. Dr. Berns is distinguished professor of neuro-economics and director of the center for neuro policy and neuroscience at Emory University, He is also the author of several popular books, including the New York times bestseller. "How Dogs Love Us: A Neuroscientist and His Dog Decode The Canine Brain." Greg, thanks so much for being with me.
Dr. Greg Berns: Oh my pleasure.
Dr. Stieg: So I've watched enough Lassie movies to really wonder are dogs smarter than humans? Can we clarify, you know, how big is the dog brain in comparison to a human brain?
Dr. Berns: So the dog's brain is actually not very big and across most of the breeds it's, doesn't vary much from being about the size of a lemon. Even if you, if your dog has a huge head like those big Labs out there, or a St. Bernard I'm afraid, most of that head is either air or muscle. Or as we say in the biz, they're either air heads or meat huts.
Dr. Stieg: I like that. So just like their human counterparts, but does a dog brain have the same regions as a human brain, the frontal lobe, the temporal lobes, et cetera?
Dr. Berns: Most mammalian brains of course have the same basic structures because we're all evolved from the same common ancestors way back. Yes, there's a frontal lobe. There's occipital lobe- all the major lobes are there. In fact, you can go down to even smaller structures, find again, all the same structures are there. You can look at the brainstem, all the nuclei are there, which, you know, as, as a neurosurgeon, that shouldn't surprise you because brains are brains, really
Dr. Stieg: One question I had is about the common ancestry that you just mentioned in regard to dogs versus humans. How long ago did this actually happen? And did dogs evolve from wolves?
Dr. Berns: That's the million dollar question in terms of common ancestors. The last common ancestor that we have with dogs themselves is actually about 80 or 90 million years ago. That is incredibly long ago. So the carnivores as they're called split off from what would later become primates a very long time ago. In evolutionary time, we're not that close to dogs. Now, what's interesting though, is that sometime, I'd say maybe between 15,000 and 30,000 years ago, blink of an eye in evolution time, is when dogs appeared. And the million dollar question is exactly when did that happen? We can say unambiguously that there were dogs in the first human settlements. So settlements around, uh, the Middle East, the Fertile Crescent. You can date fossils that are clearly dogs to about 11 or 12,000 years ago. Before that it gets a little fuzzier because people weren't living in communities, people were nomadic and they moved around. And the question is, were dogs, dogs then? Or were they wolves or were they something else? And the short answer is we don't really know yet because the fossil record only differentiates changes in bone structure. So we don't know, for example, if say a Wolf brain turned into what we now know as a dog brain, because the brains are gone. There aren't any fossilized brains that have been recovered. And so now folks are turning to genetics to try to figure this out. And it's all over the map. Somewhere between 15 and 30,000 years ago is when dogs became dogs.
Dr. Stieg: So when they were found in excavations from the Middle East, I'm presuming at that point, dogs had already been socialized within the human environment.
Dr. Berns: That seems to be the case, whatever their ancestor was, you know, and kind of my view, I, you know, I envisioned nomadic humans traveling around the world and kind of these small bands of Wolf dogs, whatever they were were kind of hangers ons, if you will, maybe living off the garbage that people discarded. But eventually, you know, getting socialized enough so that they would approach the humans and, uh, eventually become friendly with them. And then once humans stopped moving around and started living in cities, then those creatures, those dog-wolf, creatures, whatever you want to call them, started breeding with each other and became more and more socialized and very comfortable living around humans. And then, then it really took off. I would say,
Dr. Stieg: I have to ask this question. I mean, given your background in neuroeconomics and neuro policy, why dogs? What interested you in the first place about dogs and how does that relate to your background?
Dr. Berns: I think I've always been a dog person. I grew up with dogs. I've had dogs in my house for really my entire adult life. My background before I got into dogs was in neuroeconomics, which simply means that I use brain imaging tools to understand human decision making. And it was, uh, back around 2011 that had the idea, well, if we're using these tools to study human decision making, why can't we do that with dogs? Why not just train dogs to go into a scanner the same way that people do and see how their brains work. And that was, that was the beginning of it. And at first, it was just kind of one of these side projects, just to crazy idea. It literally started with one of my own dogs, you know, looking at her Cali, you know, I just wonder, it's like, wouldn't be cool if I could train her to go on the scanner and see what she's thinking. And then it just took off from there.
Dr. Stieg: We've all heard the expression herding cats. And I also, I also think about that quite often when I'm trying to manage my department, is that why you didn't pick cats? It would be hard to get them into an MRI scanner and try to train them to do that?
Dr. Berns: No offense to the cat people out there. Um, it just seems highly unlikely that you could convince a cat to do this and the way, and to be clear, kind of what we started doing was was without anesthesia, without sedation, without any restraints. And so the whole idea was to treat the dog the same way as a human volunteer or perhaps a child volunteer where they have to do it voluntarily. They have to be taught how to do it and, and want to do it actually. And so it's just hard to imagine getting a cat to do that.
Dr. Stieg: Also, the important thing I would think don't cats see things differently than a dog. I think can't see things in vertical and horizontal lines, and it's my understanding that dogs actually see forms and faces. So it would be from my perspective, I think probably easier to really assess a dog's response to some visual stimulus in a functional MRI. Is that true?
Dr. Berns: Well, dogs also have rather different visual systems than we humans do. Um, so I would say that they're both different in their own particular ways. So dogs are dichromats so they, they only see in two colors, primarily blue and yellow. They also actually don't have a fovea, which is an interesting tidbit. What that means is unlike humans and other primates who have a fovea central area of higher resolution in their visual field dogs actually have what's called a visual streak. So it's like you take the fovea and you kind of stretch it out into a horizontal line across the retina. We think that's because they evolve from predators. And so they're very good at scanning things along the horizon. But I think probably, behavioral reasons aside, cats brains are actually quite small. The dogs are small, lemon size, but the cat's brain is more like a walnut. So that makes, that makes the job even harder should we even get a cat into the scanner, which I don't foresee.
Dr. Stieg: Do you think the dog's vision has anything to do with their social ability or is it other components of the brain?
Dr. Berns: I think it's part of it kind of, we think of dogs as, as having smell as their primary sense, although they are also very visual creatures, so they, they process body language amongst each other. And there's good evidence that they're also attuned to our body language as well, as well as even facial expressions. That's something common, I would say in most predators especially predators that have a history of hunting in packs, where they have to communicate with each other to bring down prey, they use a variety of signals, which could be smell. It could be visual and it could be auditory as well. We also know that dogs have tremendous hearing to frequencies as well beyond our hearing range. So I think it's all of these things. And in many ways they may be more kind of well-rounded in their use of their senses than even we are, because smell is not something that we use as much, perhaps as dogs, maybe the dogs kind of parsed it out more evenly amongst the census, but we're trying to figure all this out, right.
Dr. Stieg: Sociability in a dog is actually so much genetic, correct? As it is in humans, or, you know, I think of my dog, my son's dog, my gosh, he has to put his paw on me every time you see, as me puts his head on my lap. He just needs physical contact all the time. In fact, the most needy dog I've ever seen, which I like, but you know, it's very different than other dogs that we've had.
Dr. Berns: When we're talking about behavior. It's always a combination of genetics and environmental experience or upbringing. What we know about dogs is they have really wide social imprinting window, which means that when a puppy is born, there's typically a window and in dogs, I think it goes up to about 16 weeks. So almost four months where they're very plastic and they will just kind of glom on to whoever or whatever is around during that period and get very comfortable with them. So dogs can socialize to humans, but if you have a dog on a farm, they will socialize to the livestock just as easily. Now, it's interesting when you compare that to say wolves. Wolves who are, for all intents and purposes still the same species as dogs, actually have a really short a sociability window, only about 10 days or so. And so after those 10 days, it's like, if they did not see a human or bond to human, then in that period, then forget it. But you can socialize them. I don't know if you want to live with them, but you can get them comfortable around humans. There's something really interesting about dogs and what happened in their social process. And I think that goes back to the evolution. We actually know a little bit about what genes might be involved in that. So we're making progress on that front earlier.
Dr. Stieg: You alluded to a dog's sense of smell. It's another thing that I marvel at when I take my dog out for a walkout, how he can just stay on there for God knows how long not moving and sniffing the spot. Are there particular scents? You know, the owner, a dog biscuit, another dog, a female dog, what is it that attracts a dog's sense of smell?
Dr. Berns: The short answer is, I don't think we know. I don't think that we have good insight into what a dog's world looks like at the, at that level. There's an ongoing debate in the detection dog community. So these are people who train dogs on, on a variety of detection tasks, which could be bomb sniffers. It could be medical detection, you name it, it could be agricultural dogs. And the debate is when a dog encounters kind of a mixture of stuff, a potpourri of scents out there in the world. Are they like getting every single scent and kind of tagging it? It's like, Oh, okay. That's Rose, that's lavender. That's roadkill from three days ago. Um, we just don't know. Is smell, like our sense of vision to them. It's perplexing to us. Uh, because olfaction is, is one of the most difficult scents to study, frankly.
Dr. Stieg: Well, that alludes a little bit to memory too. Like you said, roadkill from three days ago, that would imply that they remember from three days ago,. Does a dog have that capacity?
Dr. Berns: They certainly have memory. This goes back to what we said at the beginning that they have all the same basic parts of the brain that we do. So they have a hippocampus and in fact, their hippocampus is actually quite large for their sized brains. So they're doing something with memory, probably spatial memory. And to me it makes sense that they do have that capacity. When you look at other animals that cache food, they hide it and they store it. Even a squirrel, a squirrel will store nuts. Are they just doing that on kind of autopilot? Or are they actually thinking, I need these acorns to get me through winter? I mean, I'm anthropomorphizing, but the point is that they probably do have some rudimentary abilities in terms of longterm memory like that.
Dr. Stieg: You know I always wonder whether it's memory or whether it's just programmed behavior? Again, my dog, there's a ball by the swimming pool. He's gotta be in the pool, fetching it. And he just won't stop. I can throw it a hundred times, 200 times. He just keeps going. I'm presuming that it's just inbred behavior patterns.
Dr. Berns: I don't know. I mean, some of that, some of that is behavioral patterns, but I'm also convinced that that dog probably all animals have some form of what we call episodic memory, that they have the capacity to store memories of things that have happened to them, if you will. Which is different than memory for facts, which they probably don't have because they can't store things that way.
Dr. Stieg: I presume every dog owner looks into their dog's eyes and says, they're thinking they love me. And they start thinking about their emotions. I think it's particularly creative the way you tried to analyze dog emotions by feeding a model dog. And then in the functional MRI, looking at what happened their brain. Can you explain it to us?
Dr. Berns: That experiment was ostensibly about jealousy and there's a huge debate amongst animal researchers in general and dog researchers, and in particular about the extent to which animals experience emotions like we do. Some people researchers believe that you actually need language to have an emotion that the two are so yoked together that you can't experience something like jealousy or love, for example, because you don't have the words for it. Then, then the feeling is meaningless. Personally. I don't agree with that sentiment. I actually agree with kind of the other school, which says that these emotions, uh, that we have probably evolved from some common basic function because they serve a basic function in terms of living with each other, in terms of social emotions. Actually, this is what Charles Darwin thought. He thought that emotions and man came from something in, in animals. And actually he, he looked to dogs as, as an example. In that experiment though, we were focused on jealousy. And so what we did, we had a dog in the scanner and we, they were facing their owner. And then behind the owner, we had a very realistic statue of a dog. And from time to time, the owner would turn around and instead of feeding their dog in the scanner, they would turn around and feed this very, a realistic looking dog. And so our goal was to look at the brain activity to determine what was happening. So yeah, the dog was disappointed. They weren't getting the treat. And as a control for that, we also had a bucket. And so sometimes the owner would turn around and put food in a bucket. And so we compared that—we compare it putting food in a bucket, it's a feeding this other fake dog. And what we found was activity in a particular area called the amygdala, which is associated typically with emotional arousal in humans, as well as other things was particularly active when we fed the fake dog. And it was even more so in dogs who had a history of aggression. Putting two and two together, you kind of can start to draw this picture, that dogs with a, I called it a twitchy amygdala tended to respond to these social signals in an amplified way. And in their case, they tend to, you know, become aggressive.
Dr. Stieg: Do you think dogs have a range of emotions? Like fear, love, anger, anxiety, affection. Uh, I'm sure I'd like to know that. Cause I, you know, when I look at my dog, I'm hoping that he loves me as much as I love him.
Dr. Berns: Oh sure w you know, why wouldn't they? Very few things I think are kind of all or nothing phenomena in the brain. Especially when it comes to emotion. I think the crux of the question though, is like, how nuanced do we get into the dog's brain if we're talking love, for example. Cause this seems to be what most of us want to know is does my dog love me? The problem is, we have one word to describe, you know, dozens, if not hundreds of shades of love, right? So you have romantic love. You have parental love, you have platonic love, all sorts of types. And so the question then is which of those types or shades of love does a dog experience? I don't think we're going to be able to answer that easily because honestly I don't see a way to get at say romantic love in a dog. I'm not sure that that exists, not in the way that we think of that.
Dr. Stieg: it's hard to design, I would presume, a test that you could assess that. So that that's probably the limiting thing, correct?
Dr. Berns: Yeah. I mean, when you get into the weeds of, of dogs, reproductive behavior, frankly, it's not very romantic, but you contrast that though with wolves and coyotes and other animals, coyotes and wolves, for example, mate, for life, which is very interesting.
Dr. Stieg: We had a Yale neuroscientist on, Dr. Marvin Chun, and we were talking about human functional MRI imaging and brain function and where that's going, is the applying the use of artificial intelligence for further information. Do you think that you'll be doing that with dogs as well?
Dr. Berns: It's already happening. We're doing it . Kind of my dream has always been kind of the Dr. Dolittle version of this, which is to build a brain decoder. So yes, you need AI, you need machine learning and you're right. That's how all brain imaging is going in human research. And so, yeah, we're going to do the same thing with dogs.
Dr. Stieg: I understand that you've been very involved with the training and selecting of, of service dogs. Are there particular breeds that are very effective for them or those across all breeds? Is there a gender difference? Can you expand on that a little bit?
Dr. Berns: So it obviously depends on what you need a dog to do. In the service dog industry, where a dog is trained to assist someone who is disabled in some way. So someone in a wheelchair, for example, you see a lot of retrievers, a lot of golden retrievers and actually more Lab, Labrador retrievers. And I think in large part, that's due to their just their general easygoing friendly temperament. What's interesting to me is you go back 40 years, 30, 40 years ago, if you were talking about service dogs, you would most certainly be seeing German shepherds. And so those, those were always the dogs you saw that were for blind people and they're frankly not used that much anymore, just because the retrievers have seemed to have a better, more friendly temperament. We have been involved with studies. We actually posed the question, “Could we use brain imaging in these dogs to, to predict whether a dog would actually be a good service dog, even before you embark on the training,” which is, is quite costly and time consuming. We actually adapted some of our tasks and teamed up with canine companions for independence to test this hypothesis. And it turned out that you can, you can actually recover some important signals from the dog's brain in particular, again, coming back to their amygdala. So a dog, with a reactive amygdala, we found tends not to be a good service dog, and this is not surprising. It's like the emotional person. It's like, that's an emotional reactive dog. And we can see it in their brain before it even manifests as an overt behavior. And so that seemed to carry some predictive value.
Dr. Stieg: So the better service dog is a dog that's mellow, more even-tempered.
Dr. Berns: Exactly, exactly. That's exactly what you want. Now you might want a more reactive dog in different types of jobs, for example, or in other types of jobs, you might need an independent thinker as they say. So, so a dog who can problem solve without being trained on every specific, little detail.
Dr. Stieg: I was shocked to see that you actually have, I guess you call them service dogs for people that are experiencing post-traumatic stress disorder and, you know, turning on the lights in the room when it's dark, that I find very impressive. So there are a whole set of various emotional, psychological problems in humans that you can train a dog to help them get through that, that difficult time.
Dr. Berns: Indeed. There's a huge demand for it. There are many, many more people who would like to have dogs that can help with these problems then than dogs out there. And unfortunately it's, the training process tends to be quite expensive. So if you can find someone to train them, it can cost anywhere from probably 10 to 30,000.
Dr. Stieg: Yeah. We're talking about different breeds being effective for these service dogs—are dogs, individuals like us like human beings?
Dr. Berns: Absolutely. You know, I've, I've now probably looked at probably about 300 scans of dogs, functional MRI scans. And I can tell you that they are as variable across each other as any of the human ones that I've seen. My take is yeah, they are as individual all as we are.
Dr. Stieg: Where do you see your work going in the future? I'm sure that everybody listening now is going to be fascinated by the things you've written. Where are you going to take us?
Dr. Berns: Well, in terms of the dogs, I think I'm really focused on, on decoding. So this is the AI approach and machine learning approach to, to build some form of brain decoder, to understand, you know, based on images we can record from their brain. Can we get some sense for what the thinking, whether it's in terms of images that they might be thinking of, do they think visually, do they imagine things visually as we often do, They certainly don't have an interior monologue. I doubt. I can't imagine what that would sound like, but they might have kind of a Smell o' vision version of it. That's what I want to do.
Dr. Stieg: I read a little bit about Chaser who was able to identify a thousand toys, which to me implies that there must be either it was a program dog, or they must have a memory. Tell me about that.
Dr. Berns: Chaser was the dog of John Pilli, who lived in South Carolina and he passed away last year as did Chaser actually. So Pilli, uh, had this Border Collie who he noticed from as a puppy, just, you know, like many border collies just needed a job to do. They're there they're very unhappy without jobs to do. He was a psychology professor and he just started teaching her the names of toys and, and found that she was very adept at apparently learning the names of toys. So she could go retrieve, I couldn't, I can't possibly give all the names, but he would just give weird names to things and she would go get them. And he claims that he trained her on over a thousand objects in there as kind of ample YouTube video of her doing this. She'll go into another room to get toy out of a stack. So there's no kind of inadvertent queuing. And what's weird to me about this is, I don't think I could do that kind of task because it's like, okay, think of a thousand names for just random objects in the world with kind of no way, no kind of common sense classification scheme. Could you remember a thousand arbitrary names? It's like, I don't think so. We actually don't know what she was doing or how she was doing it. I had wanted to scan her before she died, but I never got the chance to.
Dr. Stieg: I've a hard enough time remembering names from day to day. So..
Dr. Berns: Exactly.
Dr. Stieg: That's why I was really astounded by the story. I was also taken by the fact that dogs will actually listen more intently to gibberish than a human will. A human will naturally block it out and kind of go on with what they're doing. Whereas a dog will look at you and I actually tested it on my dog this weekend. And when I was speaking nonsensically he would just sit there and look at me and actually act like he was paying attention to me. What's going on there?
Dr. Berns: Yeah. So we did a study a few years ago where we try to understand how dogs process human language and the way we set this experiment up. As we kind of built it off of a standard human experiment in, in human studies of, of language. Oftentimes you'll have someone go in a scanner and if you're in, if you want to know what parts of the brain are involved in language processing, you'll play various kind of standard words to them, the person in the scanner, and then as a control, you give gibberish words or what's called pseudo language. Obviously it's not that interesting to see what lights up, uh, when you hear a word versus just some arbitrary sound. So you need stuff that sounds like language, these words and pseudo words. We did this with the dogs, but first we had to do an experiment or actually train the dogs on what the words meant. So we use the Chaser protocol where we taught the dogs, the names of new objects and new toys, and we only had two. And then we had the owner speak those words to the dog in the scanner. And compared that to what happens when they just spoke gibberish words, like kind of think like Jabberwocky words and kind of what we found was interesting because it's opposite what we find in humans. So in humans, when, when we hear words then the language, parts of our cortex tend to become very active, more on the left than the right, um, a lot of activity in the temporal lobe and the angular gyrus and parietal lobe. And in dogs, we found the opposite pattern where the gibberish words were causing much more activity. And my conclusion from that was that dogs are processing human language in ways that are different than we do. And that I guess is not terribly surprising because they don't speak. So they don't have language production like we do. I mean, they communicate, they bark and they, they whine and they groan and, and howl, but that's very different than language. So they don't speak words. So they don't have the neural real estate to make language. And so whatever they're using to process our speech is different. And it seems to be based very much on, okay, I've heard this word before in particular context, or I have not heard this word before or this set of sounds, and I need to figure out what that means. Very different than humans.
Dr. Stieg: Greg, can you tell me, can you teach an old dog new tricks?
Dr. Berns: Yeah, I think you can. I mean, I guess it depends on how old the dog is just like humans, but we've had volunteers in this project that have run the age range from puppies. really. The service dog study was in what I'd call adolescents. So they were, you know, 15, 16 months old, but we've also had people volunteer their dogs who are, shall we politely say middle-aged meaning double digits, early double digits? So that would be 10 for a dog. And they, they seem to learn the task just fine. In fact, just this last week we certified two new MRI dogs and one of them was eight and he was spectacular.
Dr. Stieg: Everybody that goes out to buy a dog now is going on Google and trying to find what is the smartest dog? Is that true? Are those ranking lists of dog intelligence relevant? And do you ascribe to them?
Dr. Berns: I don't give much credence to those rankings. One thing I learned from the service dog study that we did, we studied 50 dogs and these were all primarily Golden Retriever, Labrador Retriever crosses. For all intents and purposes they were all the same breed. And yet they were as different from each other, as other breeds were from other breeds and, and their MRI data showed the same thing. So there was, again, this huge individual variability. One thing to take away from kind of these breed lists is those are just someone's opinion and rankings based on typically arbitrary criteria, which are rarely validated. And then you're going to have huge variation even within that breed. I would not go off of that. And plus ask yourself if you really want a really smart dog, because if you have a really smart dog, then you might have a wolf on your hands.
Dr. Stieg: I don't want any dog smarter than me. But so what advice do you give to a person buying a dog? You know, the one scenario is you're going and you're picking a dog out of the litter, or, you know, you want to save a dog and you go to the compound and you find a dog. Are there characteristics, you think that make an exceptional dog as a pet?
Dr. Berns: It's really tough. I mean, uh, it's personal, you know, and I have, I have many dogs in my house right now, but only one is my favorite. And that's Cali. What's interesting to me about her was she came from the Humane Society. So she was a rescue dog. We adopted her, she was about nine months old. So she wasn't a puppy, but she wasn't full-grown either. And I didn't think I was going to like her initially, because she was kind of a standoffish dog, she's a terrier and kind of has a terrier mentality. But what I found in the course of doing the project itself, so she was the dog I trained and it was in the training and the bonding that happened through that, that certainly I changed, but I think she changed as well. And so it's partly the dog, but it's also the human. And so it's like any relationship you have to build it. And the more you put into it, the stronger it's going to be.
Dr. Stieg: Dr. Greg Berns, author of "How Dogs Love Us: A Neuroscientist and His Dog Decode The Canine Brain." Thank you so much. It helps me understand and makes me want to believe that I love my dog and my dog loves me. Thanks so much for being with me.
Dr. Berns: My pleasure.