[Nov. 26, 2023: JD Shavit, The Brighter Side of News]
Dogs, our loyal and diverse companions, have always been a subject of fascination for scientists and dog lovers alike. (CREDIT: Grace Chon/Getty Images)
Dogs, our loyal and diverse companions, have always been a subject of fascination for scientists and dog lovers alike. From the exuberant retriever that eagerly fetches a tennis ball to the contemplative observer who pays no heed, or the herding enthusiast that orchestrates walks to perfection to the leisurely sniffer who explores every nook and cranny – the spectrum of canine behavior is as vast as it is intriguing.
But what drives these differences in behavior, even within the same breed? Erin Hecht, an assistant professor of human evolutionary biology at Harvard University, is on a quest to unravel the mysteries of canine behavior through her groundbreaking initiative, The Canine Brains Project.
In a recent talk organized by Harvard University's Brain Science Initiative, Hecht shed light on the emerging field of canine neuroscience and what we currently understand about our furry companions. According to Hecht, dogs offer a unique opportunity to study brain development and evolution. They were domesticated relatively recently, approximately 20,000 to 40,000 years ago, which is a mere blink of an eye on the evolutionary timeline.
To put this in perspective, modern humans have been around for roughly 300,000 years. This recent domestication of dogs allows researchers to compare modern dog breeds with ancient ones, shedding light on the changes that have occurred over time.
As Hecht explains, "Darwin saw dogs as a window on mechanisms of evolution. When we're looking at dogs as a natural experiment in brain behavior evolution, all we have to do is look at their brains and see what evolution did to satisfy those selection requirements."
Hecht's research laboratory conducts MRI scans on nearly 100 canine brains each year while also gathering data through owner surveys. These surveys assess various working skills in dogs, including hunting, herding, and guarding, and compare them to factors such as skull shape, body size, and breed.
The research encompasses a wide range of dog populations, from domesticated breeds like Great Danes and other hunting dogs to designer dogs, a practice that gained prominence during the Victorian era. Additionally, Hecht's team studies ancient breeds like huskies and "village dogs."
About 80 percent of the dogs living on the planet today are what's known as village dogs. (CREDIT: Creative Commons)
"About 80 percent of the dogs living on the planet today are what's known as village dogs. These are free-ranging animals that live as human commensals. So they're living within human society, but they're not pets," Hecht explains, highlighting the diversity of dog populations under examination.
One of the early findings from Hecht's lab points to significant neurological differences among dog breeds. For instance, premodern dogs, as a whole, tend to have larger amygdalae – the brain region responsible for emotional processing and memory. This heightened emotional awareness may have evolved to aid dogs in discerning which humans are more likely to offer scraps and which to avoid.
MRI machine: Modern dogs possess larger neocortices, the brain region responsible for motor function, perception, and reasoning. (CREDIT: The Canine Brains Project)
In contrast, modern dogs possess larger neocortices, the brain region responsible for motor function, perception, and reasoning. This development may contribute to modern dogs' increased behavioral flexibility and their ability to adapt to new environments.
Hecht's research further connects personality and skill differences in dogs to six distinct parts of the brain, including regions governing drive and reward, olfaction and taste, spatial navigation, social communication and coordination, fight or flight responses, and olfaction and vision. While commonalities exist among the pathways in breeds we encounter in our homes today, Hecht's work suggests that these traits are more a result of selective breeding than ancestral DNA.
"There has been very strong recent specific selection in individual breeds rather than founding effects in ancestral founding populations," Hecht notes. "So then we can look at behavior and ask whether the types of behaviors that different lineages have been selected for historically explain each dog's anatomy and these six brain networks. And it seems like there are some interesting relationships here."
Interestingly, beyond breed itself, the size and shape of a dog's head can impact these brain pathways. For instance, Hecht's lab has observed that larger dogs tend to have larger neocortices compared to their smaller counterparts, making them generally more trainable and less anxious. Conversely, dogs bred for narrow skulls may exhibit corresponding effects on their behavior.
"It stands to reason that if you're manipulating the shape of a skull, you're going to be manipulating the shape of the brain," Hecht points out. "But this confirms that dogs with these extreme skull morphotypes have impacts on their brain anatomy that likely affects behavior."
In conjunction with MRI scans, Hecht's lab employs the Canine Behavioral Assessment and Research Questionnaire (C-BARQ) to measure dogs' behavior. This survey, completed by the dog's owner, assesses various behavioral traits, including aggression, trainability, and rivalry, among others.
Hecht explains, "There was one study that collected C-BARQ data on 32,000 dogs from 82 different breeds and then performed clustering on the survey responses. And the data clustered more on the body height of the dogs than on breed relatedness. So size was a better predictor than breed in predicting temperament scores on this C-BARQ assessment."
Interestingly, beyond breed itself, the size and shape of a dog's head can impact these brain pathways. (CREDIT: The Canine Brains Project)
However, Hecht emphasizes that a dog's brain makeup doesn't lock them into specific behaviors, especially when it comes to working skills. Training remains essential for all dogs, regardless of their breed or innate tendencies.
"Training is almost always necessary. I have yet to hear of any particular breed of working dog where it's just born knowing how to do its job," Hecht remarks.
So whether you have a pit bull that behaves like a chihuahua or a Yorkie that enjoys running with larger breeds, understanding their brain may provide valuable insights into why they behave the way they do. Erin Hecht's pioneering research at The Canine Brains Project continues to shed light on the intricate and fascinating world of canine behavior, unraveling the enigmatic bonds that exist between humans and their four-legged companions.
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