Why we love dogs — and they love us back

Science & Tech

‘Harvard Thinking’: Why we love dogs — and they love us back

Samantha Laine Perfas

Harvard Staff Writer

April 29, 2026

long read

In podcast, experts break down evolution and biology of this special relationship

Nearly half of all American households include a dog, according to Pew Research. That same survey found that most pet owners, especially dog owners, consider their pets to be part of the family. How did dogs go from being wild animals to our best friends?

“Scientists think that dogs probably domesticated themselves. Nobody really knows for sure, but the current thinking is that there were probably wolves that were hanging around human settlements tens of thousands of years ago, and the wolves that were less afraid of humans and could make humans less afraid of them were able to obtain survival benefits,” said Erin Hecht, director of The Canine Brains Project in the Department of Human Evolutionary Biology.

In this episode of “Harvard Thinking,” host Samantha Laine Perfas explores the special relationship between humans and dogs. In addition to Hecht, she is joined by Alice Hoffman, author of “The Best Dog in the World: Essays on Love,” and Elizabeth Frates, an associate professor at the T.H. Chan School of Public Health and Harvard Medical School, who explains how some dogs even act as “lifestyle coaches” for their owners.

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The transcript

Erin Hecht: There’s sort of a tongue-in-cheek idea that dogs are psychological parasites, that they’ve evolved to hack our psychology and worm their way into our emotions and take over the types of psychological urges that we would normally invest in a human social partner. So I think, they maybe trick us, in a way, into thinking of them almost like little people.

Laine Perfas: Most U.S. families are pet owners, with just under half the population owning a dog, and in the vast majority of the cases, the owner thinks of the animal as a member of the family. The love goes both ways. Dogs depend on us for their survival, just as humans benefit from their presence. Research shows that having a furry companion is good for us physically, emotionally, some might even say spiritually. Why is that?

Welcome to “Harvard Thinking,” a podcast where the life of the mind meets everyday life. Today I’m joined by:

Alice Hoffman: Alice Hoffman. I am a novelist and also an alum from the Divinity School.

Laine Perfas: She’s published dozens of works of fiction, including the bestselling “Practical Magic” series. She most recently edited the nonfiction anthology, “The Best Dog in the World: Essays on Love,” which features the stories of various authors and their dogs. Then:

Elizabeth Frates: Dr. Beth Frates. I am an associate professor, part-time, at Harvard Medical School and the immediate past president of the American College of Lifestyle Medicine.

Laine Perfas: She spearheaded the Harvard Medical School special health report, “Get Healthy, Get a Dog.” And finally:

Hecht: Erin Hecht. I’m an associate professor at Harvard University.

Laine Perfas: She directs the Canine Brains Project, which seeks to better understand why canine minds and brains work the way they do.

And I’m your host, Samantha Laine Perfas. I’m a writer for The Harvard Gazette. Today we’ll look at the science of dogs and why having a furry companion can be so beneficial to our wellbeing.

How did dogs go from being wild animals to our best friends?

Hecht: Scientists think that dogs probably domesticated themselves. Nobody really knows for sure, but the current thinking is that there were probably wolves that were hanging around human settlements tens of thousands of years ago, and the wolves that were less afraid of humans and could make humans less afraid of them were able to obtain survival benefits in the form of scrapped food and maybe shelter. So then, gradually over time, we had this population of wolves that gradually turned themselves into dogs and were living around people. And that’s actually how most of the dogs on the planet live now: not inside human households as pets, but just around. They’re called village dogs.

“There’s sort of a tongue-in-cheek idea that dogs are psychological parasites, that they’ve evolved to hack our psychology and worm their way into our emotions … and maybe trick us in a way into thinking of them almost like little people.”

Hoffman: It’s interesting because I have a new dog and she’s a Tibetan terrier. And when I finally did research to try to understand why, I’ll be walking her, and she’ll leap into some strange man’s arms, that they were village dogs. They were raised as village dogs. They weren’t connected to one person, but to the entire village. That’s who she is. I’m not used to that, but in my further research, I found that they also make very good support dogs and therapy dogs because they’re so friendly and because they don’t have stranger fear; she never barks when someone comes to the door. She’s really a village dog, but I don’t have a village, really. So I think I’m going to change my life to suit my dog.

Frates: I find that so fascinating, Alice, because what we find in the research around lifestyle behaviors and pet owners or dog owners is that the human in the relationship prioritizes the dog. For example, I must go out and exercise my dog. Now we know that humans need 150 minutes of moderate-intensity physical activity each week, and humans are much more motivated to do such when the human believes the furry friend needs this. And even in terms of when a human is thinking about nutrition, many people are thinking about the preservatives in their dog’s food and the quality of the dog food as well as thinking about their food. Their behaviors around food and what they believe to be healthy, they want to do for their dog.

Laine Perfas: You could make the argument that initially, dogs benefited the most from being around humans. But as we have seen, it’s this true symbiotic relationship. So I wanted to talk a little bit about the ways that we see the benefits for dogs. And then what is it for humans that we are also benefiting from this relationship?

Hecht: I could talk about the benefits for dogs. They are truly adapted to live in the human world. They cannot exist out in the wild without us. I guess maybe an exception is dingoes: They have adapted to live out in the wild, but they really are an exception. Dogs have to live with people. They have to live in a human environment, and they need us as social partners. We are their primary social partners. They bond to people. They treat humans like conspecifics, like members of their family. And research has shown that when dogs and humans interact, both members of that pair release oxytocin in their brains, which is a hormone that’s involved in social bonding. It potentiates the action of dopamine in your brain, which is a feel-good reward hormone. And it also inhibits stress chemicals in your brain. So it makes you feel good, and it also helps you not feel bad. So if a dog has a bond with a person, just the presence of that person can help buffer negative experiences for the dog. And the reverse is true also for the person. The presence of that dog can help buffer negative experiences for the person. And that effect is so real that dogs can actually function as health aides for people who have PTSD or anxiety disorders.

Hoffman: I feel like in my life, in my personal life, that I was always closest to the dog. That was my primary relationship. I grew up in a very dysfunctional family. I felt like I didn’t have a family: I had the dog. And it’s always been like that for me, that my main relationship has been with the dog, probably why I’m divorced, but anyway, that’s another story. But now that I have this other dog, that we are not each other’s primaries, I’ve felt more stress than I have a freedom from anxiety. And I realize, as Beth was saying, “I have to change my life to suit this dog.” And in a way, it maybe is what I need because it’s opening my life to other people. I feel like maybe it’s meant to be that it’s not just me and a dog sitting in a room together crying, that maybe this dog is leading me to other places.

Frates: I found my first dog, who was a goldendoodle named Reese. I got her with my family when my kids were young. I was afraid of dogs. When I was a child, a neighborhood Doberman was with us at a skate park. I was with the dog’s owner child, and we were skateboarding tandem together, and we were a little bit out of control and going a little crazy. Probably going to crash. And the Doberman grabbed me with its teeth on the shoulder. I viewed this, as a child, as the dog biting me and was petrified of dogs thereafter. Now, being a dog person, I see this whole scenario and I say, “Oh, the Doberman was trying to save me and its owner from potential disaster.” My husband loves dogs, is a dog whisperer, and finally convinced me to agree to getting this dog Reese, the goldendoodle. And what I want to share in terms of personality and a dog helping us was that at the time I was the mom of two young boys, was working. I also had older parents. There was a lot going on, and I wasn’t very social, even though I love people. I love people. I love my friends, but I was really hunkering down and just getting by, just doing what I needed to do for cooking, cleaning, parenting, work. And then I got Reese and, just as I said earlier, she needs to go out for a walk. So I would go out for a walk in the neighborhood. Suddenly I had 20 new friends. I was suddenly invited to dinner parties and dog play dates and events that the ladies in the neighborhood were having. I made so many new friends and became so much more social because of Reese.

“When I think about a dog now, I think about them as a lifestyle medicine coach because one of our pillars is physical activity. Another pillar is stress reduction. And then we have the pillar of social connection.”

Laine Perfas: One thing, Beth, you mentioned in your response was the personality of dogs. Are there dogs or dog breeds that are more naturally friendly, more intuitive, or more aggressive? How do their genetics versus their environment affect how they behave around us?

Hecht: This is something that scientists have been really interested in for a long time, and it’s been a difficult thing to study because it’s tricky to separate the genetics from the environment, because those things tend to not be randomly distributed. Certain types of people end up liking certain types of dogs. If you’re a really athletic person, you might like a dog that’s super athletic, and certain types of breeds are more athletic. And then you wind up with dogs that have personality traits that kind of go along with an active lifestyle. But all that is to say, there are breed differences in behavior and personality. You can trace them to variants in the genome that we know are related to similar aspects of personality in humans. But breed doesn’t determine everything. Genes don’t determine everything. You might think of it as a breed sets a range where personality might fall into for a particular dog, and then the dog’s environment and upbringing and a little bit of random chance kind of sets where that particular dog is going to land within that range.

Frates: I also think this is good to know for anyone who’s listening to this and thinking, I really need to get a dog for my health. I think it was 2016, soon after I got my first dog, my colleagues tapped me for this Harvard special health report on “Get Healthy, Get a Dog.” I dove into all this literature on how the dog does in fact help us as the human to attain the physical activity guidelines, which I mentioned. And then there’s now guidelines on nature, recommendations to get out in nature for 120 minutes per week. The dog absolutely helps us with that. When I think about a dog now, I think about them as a lifestyle medicine coach because one of our pillars is physical activity. Another pillar is stress reduction. And then we have the pillar of social connection, which we’ve talked about a little bit in terms of feeling connected, as Alice was saying to the dog itself. And then I mentioned how my dog Reese helped me socially connect outside my own home. So this dog can help us in many of our lifestyle behaviors, and also is a real mindfulness instructor. The dog is just living in this moment. Happy to be outside. Smelling everything in the present, right now, right here. Really living with its five senses.

Laine Perfas: Who should not get a dog?

Frates: Dogs come with a lot of responsibility. They take a lot of time to love. You need to love that dog and treat that dog like a real member of your family. You really do need to have time. And not everyone can afford a dog. There are vet appointments, there’s food, there’s time out of work that you need to spend with the dog. I love dogs and I do believe they’re great for our health. And again, there’s data that shows people who own dogs tend to have lower blood pressures, tend to also have lower cholesterol levels, even. This is likely all due to the movement that they’re encouraged to get and the stress resiliency. Yes, dogs are wonderful for health, but we also have to think about what responsibilities come with that dog. And perhaps piggybacking on the breed, and also researching the breed, and does that breed match your lifestyle.

Laine Perfas: I wanted to pick up on something you said about how important it is to treat dogs as if they’re a member of our family. I think sometimes with animals, we assign a lot of human characteristics to them. We want them to be like us. What do we know about their actual emotional depth and capabilities compared to humans?

Hecht: So first of all, I think dogs absolutely have emotions. They have an inner life. They experience the world, they have an awareness. But I think we shouldn’t assume that their emotions are identical to ours or that they experience the world the same way that we do. And some emotions that we experience might have a little bit of cognitive complexity that doesn’t exactly map onto what dogs experience. One example might be jealousy. I think, when humans experience jealousy, we have some sort of complex understanding of somebody having something that we don’t have and what it would be like if we had it and why it’s not fair that we don’t have it. There are a lot of layers going on there. If you have a dog, you’ve probably had an experience where it feels like your dog is jealous, either of another dog getting something that your dog’s not getting, or you’re giving attention to another dog and your dog starts to get upset or something like that. So it starts to seem like your dog is jealous. I would guess that your dog is experiencing something like jealousy, but their internal awareness probably doesn’t have all of the layers of complexity that we have. But things like love and fear and happiness and joy, curiosity, playfulness, I think they have all of that.

Hoffman: I have a book that’s an anthology, and 14 fantastic writers like Amy Tan and Isabel Allende and Roxane Gay all wrote about their own experiences with dogs. It was so interesting to hear about other people’s most intimate relationships with their dogs. And I felt like most of these people, I knew. I knew their writing and I knew them. But I got to know them in a different way when they wrote about their dogs because it was a certain kind of intimacy and depth that I had never seen before. And it was just a different way of knowing them to know how they felt, what their relationship was with their dog. I think you’re so right in that we assume that they’re feeling certain things that we are feeling, but it’s pretty hard not to assume that when you’re so close to them; you’re living in such an intimate space with this other creature.

Hecht: Our minds are built to understand human minds really on a fundamental level. And I think dogs have probably evolved to tap into that. There’s sort of a tongue-in-cheek idea that dogs are psychological parasites, that they’ve evolved to hack our psychology and worm their way into our emotions and take over the types of psychological urges that we would normally invest in a human social partner. So I think they maybe trick us in a way into thinking of them almost like little people. And that probably helps them integrate into human families. But I wonder if, in some ways, it could also hurt them. If we don’t also keep in mind that they’re not humans and they have some different needs than humans do that we also have to account for.

Hoffman: Yeah, my current dog does not feel like a human. And I think that’s part of the reason I have a little bit of trouble relating with her. And she’ll do things like sit in a darkened corner staring, and I’m thinking like, “What is she seeing that I’m not seeing?” We’re like in two different worlds. I do feel that with her.

Laine Perfas: Alice, are there any essays from your book that stood out to you regarding people’s different relationships with their dogs?

Hoffman: One that I love is by Roxane Gay, and she said she didn’t grow up with dogs. Haitian families don’t usually have dogs. They’re like village dogs in Haiti. And her wife wanted to get this dog and was a dog person, and they got this dog, and Roxane felt that the dog didn’t like her. And she was then very upset and depressed that the dog didn’t like her. By the end of the essay, she is that dog’s person. And things just completely changed. But there were several things. Jodi Picoult also has an essay about a dog that really didn’t like anybody, and she had several dogs. So it was like, it was interesting to see how it’s not all the same, where you just get this dog and you just love each other, that these relationships are all so different.

Frates: In our family, it seemed that our dog, Reese — by the way, she lived a beautiful life of 12 years, and now we have Athena, who is a German shepherd, a very different dog. But using the example of Reese, the goldendoodle, when the boys were younger, and for me as an adult, middle-aged woman, it seemed that with Reese, she was the unconditional love that everybody wants and needs at times. And I know, as a lifestyle medicine expert, physician, coach, listening is key to any relationship. I believe that Reese had this capacity to sit at attention and listen to me, to my kids, almost like a little lifestyle coach, and almost respond with empathy, it seemed to me. Reese could behave in a way that led us all to feel she loved us so much and understood us and would even lick you right when you were sensitive or if you were crying. She would come to you, actually reach for you and sit by you, maybe even sit on your foot when you were upset, near crying, not even yet having tears.

Laine Perfas: I grew up with dogs. I am currently a cat owner, but growing up with dogs, I’ve got to say it was only when one of our dogs died that I ever saw my dad cry. My brother, very stoic, but will weep at movies where the dog dies to the point where he won’t even watch them anymore. Dogs have this capacity to bring our emotions to the surface in a way that seems special.

“When we get a dog, we know, unless we’re a certain age, you know that you’re going to probably outlive your dog, and there’s something just tragic from the beginning about that.”

Hoffman: I think part of it is that they don’t live long enough, and so there’s always something kind of tragic about that. There’s one essay in the book that I did by Emily Henry, who’s a wonderful writer, and she starts her essay with, “The dog dies in this. Before we go any further, you should know that.” When we get a dog, we know, unless we’re a certain age, you know that you’re going to probably outlive your dog, and there’s something just tragic from the beginning about that.

Frates: I think losing a dog is really a challenge for many people. It certainly was for me. It was my first dog. So I’m an adult woman, and I didn’t understand the depth of the grief, losing a dog. And I will say that I was thinking, I don’t think I can do this again. That’s important for people to understand when they want to get a dog, and get a dog with a family that has children — because my children, it was also hard for them. But I wouldn’t change it. I wouldn’t not get Reese, no.

Hoffman: I know that when my dog passed away, Shelby, which was about a year ago, and we were extremely close, we were together every moment. She was my soul sister and very special to me. And afterwards, I joined a grief group, and people were so deeply in grief that oh, I couldn’t bear it. Also what was interesting, none of them had replaced the animal that they had lost. And I rushed to replace, which was a mistake. I now realize why these people hadn’t: They needed a long time to grieve, and I think sometimes people, and myself included, don’t really understand how long it takes to get over something like this. So I left the group that night, but I wish I had stayed. I think I was too afraid of their grief.

Hecht: Alice, I think you hit on something I wasn’t quite sure how to put into words. I wonder if there’s this layer to human relationships that is complicated. It involves language and rationalizations and all this complexity — and with dogs, it’s just really simple and emotional and raw. And maybe that’s why losing a dog is really hard. And why dogs can just get right to your emotions in a way that sometimes people can’t.

Laine Perfas: People are complicated, like you said, Erin, and I wonder if there is something about dogs that does provide that space that is a little bit more accessible to people. We’ve learned so much about dogs and the ways that they have affected and changed us. What are we still hoping to learn about dogs, both dogs themselves, but also the relationship they have with humans?

Hecht: For me, one of the things that I hope that we’ll learn that our lab is working on right now is how to help dogs that have experienced trauma. Dogs that have experienced stressful events early in their life, just like people, often have lingering challenges, emotional and social challenges, for years to come. People who have dogs that have these kinds of challenges often struggle a lot to try to deal with things like separation anxiety or reactivity or tearing up the couch when the person leaves the house, that type of stuff. We have some treatments, but they’re not great. We have seen from some research in our lab that it seems like different breeds of dogs have different levels of sensitivity to early life stress. Some breeds seem to have pretty low sensitivity to early life stress. So lucky them, they can go through difficult things and be resilient and bounce back. And other breeds seem to have pretty high sensitivity, so they’re more likely to be more impacted. What this tells us is that there’s probably some genetic underpinning, some genes that we could identify that are either conferring resilience or sensitivity. If we could identify those genes and the biological pathways that they’re involved in, that might lead us to treatments. So that’s something that we’re working on now, and we’re actually enrolling dogs that have experienced early life stress and that have behavior challenges as a result. So if there’s anybody out there that has this type of dog that’s within driving distance of Harvard, we’d love to study them.

Frates: I think on the medical side, perhaps people have heard that dogs can sense diabetes and can be helpful for patients who have diabetes in detection of their hypoglycemic episodes. I think that better understanding how a dog could help a human manage, even, seizures. Some dogs can help with seizure management. I’ve seen studies with migraines and narcolepsy. So how can the dog use its special capabilities to help the human manage some chronic conditions that can be really debilitating? That research is ongoing, and it’s powerful. It lets the dogs do a tremendous job to help their own humans. Now, I’m giving some sort of human qualities to the dog, but I feel that the dog would feel value and also feel perhaps pride and be happy to be able to help in this way, because surely they know when their owner is suffering.

Hecht: Yeah, that’s really interesting that you mentioned that. Our lab is actually also studying these service dogs and medical detection dogs. I absolutely agree with what you say. I think that this bond between the dog and their handler is really crucial, and I think that most handlers would agree that their dog cares about them and wants to help them when they’re in trouble. A surprising thing that many people don’t know is that about half of the dogs that go through training to have these types of really specialized working roles, they don’t make it through training. It’s a really high bar to pass to have these really challenging working roles. The organizations that are breeding and training these dogs, they’re really struggling because they’re providing these dogs for the people that need them at either low cost or often no cost. They’re struggling to provide the number of dogs that are needed, with a large number of dogs washing out. As a result, there are often multi-year waiting lists to get a dog of this type. So one of the things we’re working on in our lab is to try to figure out what’s going on in the brains of the dogs that are doing a good job, and can we use that information to help these organizations produce more dogs more quickly and more efficiently?

Laine Perfas: Does anyone have any advice for someone who doesn’t have a dog but is thinking about getting a dog?

Hecht: You could foster a dog, or you could go to your local humane society and volunteer to walk dogs and see how you like that. Get a little practice run before you commit fully, so that way you can make sure that it’s really something you want to do before you take it on.

Frates: I like that idea. Maybe dog-sitting for someone who has a dog, living a little bit with a dog could be helpful. Even going to a park, a dog park with a dog owner. Because I found that very overwhelming as the dog owner that was afraid of dogs and is new to dogs and came to the dog park with all the dogs jumping and everything happening. Having some experience with those dog-owner activities may be fun and also helpful. Reading a book about dogs, what it takes to care for a dog, what a responsibility it truly is, and are you ready for that emotionally, financially, family-wise. Also just doing a little bit of research on breeds, or if you want to go for a shelter, I would say researching how to be the best dog parent of a dog who’s come from a shelter whose background you don’t know, maybe preparing for that.

Hoffman: I agree so much with Erin and Beth. I think, like a lot of things, part of it is luck. It’s like falling in love, and you just never know what’s going to happen. You’re just going to have to wish for the best. It takes a lot out of you. It’s a huge commitment. Sometimes it works out, sometimes it doesn’t. But you’re in it. And so I think it makes you work harder to have a really great relationship that is going to be maybe one of the most important relationships in your life.

Laine Perfas: Thank you all for this really great conversation.

Hecht: Thank you very much.

Frates: Thank you.

Hoffman: Thanks.

Laine Perfas: Thanks for listening. For a transcript of this episode and to find all of our other episodes, visit harvard.edu/thinking. And if you like this podcast, rate and review us on Apple and Spotify. Every review helps others find us too. This episode was hosted and produced by me, Samantha Laine Perfas. It was edited by Ryan Mulcahy, Paul Makishima, and Sarah Lamodi. Original music and sound design by Noel Flatt. Produced by Harvard University, copyright 2026.

Recommended reading

“Loving your pup may be a many splendored thing” by The Harvard Gazette

“Quiz: How well do you know your dog?” by The Harvard Gazette

“Get Healthy, Get a Dog” by Harvard Medical School

“Does your dog care if you die?” By The Harvard Gazette