We pick up after them, order them subscription boxes filled with treats and tote them around in purses on public transportation. In today’s society, the freshly groomed, pampered mutt nuzzled between our couch cushions couldn’t be further from the fierce, wild animal that once had to fend for itself against predators.
That’s because humankind’s best friend is an evolutionary freeloader, according to Courtney Sexton.
“Dogs have essentially outsmarted us,” says Sexton, a scientist studying how the domestication of dogs could inform our knowledge of human evolution. “They have evolved to be the laziest creatures in the world. They don’t have to do anything. We do everything for them.”
Sexton is an AAAS Mass Media Fellow writing for Smithsonian Magazine as part of the 10-week program that pairs scientists with journalism organizations. Her fellowship represents a homecoming for the trained wordsmith who started her career in 2012 at the Smithsonian National Museum of Natural History in communications and public relations.
Passionate about conservation, Sexton eventually landed at Defenders of Wildlife, conferring with experts and scientists to promote the organization’s work with dogs’ canine ancestor – the wolf.
As her 30th birthday approached, she planned a role reversal:
“I decided I wanted to be the expert,” she says.
This led her to pursue a Ph.D. at George Washington University’s Center for the Advanced Study of Human Paleobiology working in the Primate Genomics Lab under Brenda Bradley.
Sexton, who expects to graduate in 2022, is particularly interested in how dogs, which have coevolved alongside humans for millennia, could hold some clues to the mystery of human evolution.
“In the tens of thousands of years that they’ve been hanging out with humans – which from an evolutionary perspective is not very long – dogs have developed an incredible way of communicating with us without words,” Sexton says. “This can potentially inform how we used to communicate before words and how people today still communicate nonverbally.”
One of Sexton’s earliest studies focused on dogs’ propensity for cross-modal matching. That is, the ability to recognize a human, dog, or other object, across different sensory presentations.
Now she’s in the middle of her dissertation, which focuses on the facial expressions of dogs, an interest inspired by her late dog Remy, a black and white hound with a goofy, playful personality.
This research, she says, is based on studies of primates that show predominantly social species having greater diversity of face coloration – a tool that seemingly aids in exaggerating their expressions. As for dogs, scientists have already been theorizing about their tendency for using "puppy eyes" to get a treat or affection from their owners. Recent research has suggested this puppy eyes expression has resulted from the evolution of dogs' muscles around their eyes. And while puppy eyes could be an effective way for dogs to communicate and bond with humans, Sexton is looking at other dog facial expressions, too.
“Along similar lines of research in primates, we know those with more plain faces are more behaviorally expressive,” she says. “They have more actual muscle movements in their faces, because they don’t have the benefit of a colored eyebrow that’s going to exaggerate an eyebrow lift, for example.”
Sexton aimed to collect in-person data this summer until the coronavirus pandemic sidelined those plans. In the meantime, she’s collaborating with Erin Hecht at Harvard’s Evolutionary Neuroscience Laboratory in recruiting participants to upload videos of dogs reacting to various stimuli.
And while watching dog videos might seem like a dream, it’s actually arduous business.
Each clip is analyzed frame-by-frame using DogFACs (Facial Action Coding System) to identify and code specific movements. Another program, DeepLabCut, will help Sexton pinpoint underlying muscle movements algorithmically.
After completing her studies, Sexton dreams of working at the intersection of animals and society, perhaps at an animal welfare nonprofit or training conservation dogs to sniff out invasive species or track endangered animals.
Until then, she’s raising her new hound puppy, Sonder, who was rescued after being abandoned. Her dog Remy was adopted from a high kill shelter.
This situation of her dogs – all too common – speaks volumes for the hardships dogs experience when their care is misunderstood by humans.
“People don’t realize how much work it is to have a dog,” Sexton says. “The more we can understand how their minds work and how we can better communicate with them, the better we can improve the outcomes for dogs who might be in the shelter.”
Dogs, after all, have been our best friends for thousands of years – an evolutionary romance for the ages.
In particular, Sexton thinks about the trajectory of our relationships with canine companions in a society that’s breaking with in-person, nonverbal communication. For example, at the lunch table, we bury our faces in our phones. Many of us stare at computers all day.
For dog owners, however, the return from work in the evening provides a brief reprieve. Our smiles expand as we cast wide, affectionate stares into the eyes of our tail-wagging sidekicks and utter those magic words, “Who’s a good dog?”
“We’re sliding backwards with that direct form of (in-person) communication with each other,” Sexton says. “Maybe dogs will be a lifeline for us.”
