READING #7 ― Dog & Human Evolutionary Alliance



Converging with Canines: Are Humans and Dogs Evolving Together?


[1] In our man-made world, it can feel like everything is converging all at once. Indistinguishable glass skyscrapers sprout up in cities all over the globe, near identical car models vent carbon dioxide into the air on different continents, and people around the world see their waistbands expand as they gulp down the same McFood. Global economies are more connected than ever, with natural disasters in Japan, sovereign debt issues in Europe, and rumors of Wall Street misdeeds shaking worldwide markets within minutes. Even the social media that deluge us with information seem like they’re growing more and more alike, as we now drown in unending streams of look-alike feeds, postings, messages and links from Twitter, Facebook, Google+ and others.


[2] You may wonder whether the forces of convergence are a recent phenomenon, a product of human technology, or whether they may have deeper roots in the natural world. In fact, convergence can and does occur in the realm of biological evolution, albeit at a more comfortable pace. For example, “convergent evolution” occurs when different species independently evolve similar solutions to comparable evolutionary pressures. A classic example of this is the development of wings and the ability to fly by birds, bats and pterosaurs.


[3] Closer to home, scientists at the Max Planck Institute for Evolutionary Anthropology have concluded that we may be undergoing a process of cognitive convergent evolution with dogs based on our social relationships over thousands of years with these “best friends” of ours. In a paper published in Trends in Cognitive Sciences, Brian Hare and Michael Tomasello reviewed a large number of studies focused on canine, human, and non-human primate social and communicative skills and reached some interesting conclusions.


[4] They began their analysis by focusing on research showing how well domestic dogs do at interpreting human social and communicative behavior. For example, dogs excel at tests in which experimenters hide food in one of several opaque containers and then signal where it has been hidden by pointing, gazing, bowing or nodding, or placing markers in front of the target location. The dogs easily interpret this type of cue, passing tests such as these on the first attempt and performing correctly even when humans try to trick them by walking towards the wrong container while pointing in the opposite direction to the correct container.


[5] Also, studies have shown that dogs are aware of what humans can see. For instance, if a human turns around during a game of fetch, the dog will almost invariably bring the ball back around the human and drop the ball in front of his face. Similarly, dogs have shown that they prefer to beg for food from humans whose eyes are visible than from ones whose eyes are covered with a blindfold or bucket, but are more likely to approach forbidden food when a human’s eyes are closed.


[6] Indeed, dogs actually consistently outperform chimpanzees and other primates at these types of skills, even though, in areas of non-social cognitive performance, dogs do not do so well. For example, non-human great apes are much better at making inferences about the location of hidden food based on non-social cues (such as a tilted board that might be tipped up by hidden treats) and at tests that require them to achieve food rewards by, for example, reeling in food attached to strings. With this in mind, Hare and Tomasello turned to whether domestic dogs’ specialized social skills are likely to be due to convergent cognitive evolution with humans or whether another explanation is more plausible.


[7] First, they considered the possibility that dogs learn to recognize human social cues based on their experiences growing up in human households. They found, however, that studies show that even puppies as young as nine weeks old are adept at solving problems using human pointing and gaze cues, and that puppies raised without much exposure to humans are equally skilled at interpreting these cues.


[8] Then, they considered whether domestic dogs may have simply inherited their social skills based on their common ancestry with wolves, since wolves are, after all, pack hunters who need to be able to follow complex social interactions with other wolves and with prey. However, although wolves are generally equal to or better than domestic dogs at memory tests and tasks involving general problem-solving abilities, wolves (even those raised by humans) are simply unable to match the performance of dogs at spontaneously using human social cues to solve problems.


[9] Next, the researchers sought evidence for the evolution of social skills in dogs through their long-term relationship with humans. They looked at a population of domesticated foxes, where the selection for breeding had been based solely on the tendency of individual foxes to be non-aggressive and fearless around humans. Interestingly, these foxes were just as adept as dogs in using and interpreting human social cues, and far better than a population of control foxes that had been bread randomly with respect to their attitude towards humans.


[10] Based on all of these comparative findings, Hare and Tomasello concluded that the best explanation for dogs’ specialized social skills is that they evolved as a consequence of dogs having been domesticating by humans, representing a case of convergent cognitive evolution. Interestingly, Hare and Tomasello went further and, based on their review of the research on domesticated foxes, concluded that the evolution of specialized social skills in domesticated dogs may actually have been an incidental byproduct of an initial decision to select based solely on nonaggression (as opposed to social intelligence).


[11] Finally, turning to primate evolution, Hare and Tomasello speculated that a similar process may have contributed to differences between human and chimpanzee social skills. Under what they refer to as the “emotional reactivity” hypothesis, they predicted that differences in temperament between humans and other primates may help explain some of humans’ extraordinary social cognitive abilities. They point to studies showing that chimpanzees’ willingness to cooperate with each other can often be limited by lack of social tolerance for one another resulting from fear and/or aggression, and contrast this to a more socially tolerant temperament that may ultimately have enabled our hominid ancestors to develop flexible forms of cooperation and communication. In other words, humans underwent a form of self-domestication leading to greater social abilities, thereby convergently evolving with our canine companions who were undergoing the same process. I’m not sure I entirely buy the notion that we humans are so exceptionally tolerant, but I have noticed that you’ve started to look a bit like your dog.


Canine and Able: How Dogs Made Us Human

Colin Groves

The Conversation | June 6, 2012


[1] What role have dogs played in human evolution? Woof … now there’s a question. Anthropologist Pat Shipman, in a recent issue of American Scientist, suggests dogs gave our human ancestors an advantage over Neanderthals when they arrived in Europe. Dogs, she argues, made a real difference to the success of the hunt. They respond to human communication— even to the direction in which our eyes are turned. She also points out dog remains have been found— (controversially)— in sites in Belgium, the Czech Republic and as far east as the Altai Mountains in Siberia, going back as far as 33,000 years.


[2] Of course Shipman, who works at Penn University, is not the first to have suggested a close relationship with dogs provided an advantage for humans. Catalyst presenter Dr Jonica Newby, in her 1997 book The Pact for Survival, proposed more or less the same thing, citing the then-unpublished work of veterinarian and author David Paxton. Around the same time, I myself was impressed by a DNA study by Vila and colleagues that seemed to suggest dogs had separated from wolves at least 150,000 years ago, and that they and we had begun to establish a symbiosis as long ago as that, leading even to humans’ sense of smell being reduced because our association with dogs had rendered it unnecessary.


[3] "The relationship was stable over 100,000 years or so, and intensified during the Holocene epoch into mutual domestication. Humans domesticated dogs, and dogs domesticated humans.” Now David Paxton, cited extensively by Newby, has published his ideas himself, going into some depth about such things as the loss of the sense of smell, and the advantage that dogs helped our ancestors to gain over Neanderthals.


[4] It turns out that the “at least 150,000 years ago” date is wrong. The geneticist Simon Ho and his colleagues have found the initial rate of DNA evolution appears to be extremely high, and slows down to the “molecular clock” rate only after 1m years or so. They haven’t done the recalibration for the dog-wolf separation time, but under the conditions they set in their paper it has got to be less than 100,000 years. And the “sense of smell” idea will probably not hold either, because there are no wolves, so no potential ancestral dogs in Africa, where modern humans originated; yet the sense of smell is reduced (as I documented in my 1999 paper) in all humans, not just non-Africans.


[5] So the human-dog symbiosis occurred in Eurasia, and dogs spread into Africa only after that. We don’t know how early this might have been, and it could indeed have been very early, so that it affected all modern human populations alike. Where, actually, did this symbiosis occur, and when did it lead to domestication? Generally, it has been supposed that the dog is descended from the pale-footed wolf, Canis pallipes, which lives in the Middle East and India. On the other hand, the earliest apparent dogs come from Europe, inhabited then as now by the grey wolf, Canis lupus.


[6] It has also been argued that these early Eurasian dog-human associations were dissolved when the Last Glacial Maximum forced the human populations to contract back to warmer climates, so that after the recession of the ice ages the dog-human association would have had to have begun all over again. I do not see why dog-human associations could not have moved south along with the human populations when the ice came. Indeed, there’s no reason why such a symbiosis could not have occurred independently in different parts of Eurasia— dogs could also have been exchanged between different human populations— the descendants of grey wolves and pale-footed wolves intermixing (they used to be regarded as just races of one species anyway).


[7] The final question is: when did the symbiosis become actual domestication? The earliest “real dogs”, that everyone would agree were domesticated, are buried along with their human owners in sites towards the end of the Pleistocene: first at 14,000 years ago in Bonn-Oberkassel in Germany, and just a little later in the Middle East. But these signs of domestication, and close companionship between humans and dogs, very obviously do not denote the actual beginning of human-dog association, and this is quite consistent with those early dogs that have been claimed 33,000 years ago. But the principle holds: dogs have made a great deal of difference to us. In a way, as Pat Shipman and David Paxton alike have argued, they really have made us human.


How kindness built civilization

Gareth Cook

Boston Globe | June 5, 2011


[1] It’s about time the dog got a little more respect. If you’ve ever owned a dog, be it a prize purebred or a lovable mutt, then you know that they are smart. Well, now science is catching up. In some ways, it is increasingly clear, dogs can be even more intelligent than chimpanzees, who sit much closer to humans on the evolutionary tree. And this remarkable gift, according to a fascinating new theory, reveals something profound about the origins of intelligence— and, possibly, the origins of our own humanity.


[2] For many decades, the dog received relatively little scientific attention, explains Brian Hare, the Duke scientist who has offered the new theory. For Hare, this changed after a conversation with his academic adviser, scientist Michael Tomasello. The two were discussing the limits of chimp intelligence. Although chimps are considered socially sophisticated creatures, they struggle to understand even basic human gestures like pointing.


[3]Young children follow a pointed finger, and know that the thing being pointed to is important. But this requires tremendous cognitive leaps. It requires knowing that there is another animal out there with thoughts of its own. That this other animal knows something that I don’t. That it is trying to communicate to me. The fact that even our closest living relatives have trouble doing this suggests its difficulty.


[4] Yet Hare had a thought: My dog can do that. Indeed, back in his parents’ garage, with a video camera running, Oreo and Daisy easily passed the test. Hare placed two cups on the floor, one with a treat underneath. He pointed to the right one, and a dog went to get the treat. Since then, researchers have found many ways in which dogs outsmart chimps. In another experiment, there are two humans, one with a blindfold: Which one do you beg for food? Dogs get that. Or if there is a forbidden treat, dogs are more likely to understand they should steer clear if a human’s eyes are open.


[5] Where, Hare wondered, do these abilities come from? The answer came from an amazing experiment in Siberia. In 1959, Russian scientist Dmitry Belyaev set out to understand domestication. He gathered wild foxes, and separated them into two groups. One, he bred randomly, as a control. The second, he bred for kindness. Only the foxes that were the nicest to humans— the ones that would approach a person without fear or aggression— got a chance to mate. By the time Hare visited Belyaev’s old compound in 2003, this selection process had been repeated over many, many generations. He tried his two-cup test with the wild group, and they failed. The nice foxes, though, were just like the dogs— they understood pointing. They had leapt past chimps.


[6] Hare suggests that dogs went through essentially the same process, over a much longer period. Many thousands of years ago, wolves began to approach human settlements, looking for scraps. Some of those wolves would been less fearful, less aggressive. These animals were rewarded with more food. Over time, these wolves became our dogs. To understand what makes this insight so important, with implications for our own origins, remember that Belyaev’s foxes, and the early dogs, were not selected for intelligence, but for niceness. The animals became nice, and intelligence followed naturally.


[7] Chimpanzees are clearly smarter than dogs in many ways, says Hare, who heads the Canine Cognition Center at Duke University. But chimps are also emotionally volatile, so much so that they can find it hard to cooperate, even when it’s clearly in their own interest. A chimp’s social abilities have been circumscribed by its emotional explosiveness.


[8] Human intelligence is often described as a steady accumulation of new kinds of smarts, as the brain expanded. But Hare has come to believe this would not have been possible unless our species first made an emotional breakthrough— the ability to tolerate each other, to be kind enough, and patient enough, that we could cooperate more deeply. This led to language, tools, and civilization. It’s an insight that Hare would not have had were it not for dogs. And so it deserves to be dubbed the Wisdom of the Dog: To be smart, first play nice.


How the Domestication of Dogs Changed Civilization

Linda Cole


[1] For centuries, dogs have been used by humans to do a variety of jobs. Before the invention of gunpowder and firearms, canines were instrumental in helping hunters put food on the table and protect their family. However, the greatest and most significant impact of dog domestication was how it changed human civilization.


[2] History is an intriguing and complicated mixture of stories passed down from generation to generation, and documented accounts preserved in paintings, sculptures, ancient writings and cave drawings. Archaeological discoveries add important information about events that took place thousands of years ago to help scientists unfold the why, where, when and how.


[3] When we use the word “theory” it means an idea or hunch about something. In the scientific community, theory is how researchers interpret facts. During the very early years, our closest now-extinct human relative, Neanderthals, and modern humans (Homo sapiens) co-existed for a time in Europe and Asia after humans migrated from Africa into Neanderthal territory. Both used fire and tools, and were expert hunters, but Neanderthals became extinct while humans flourished. The general consensus as to why Neanderthals died out is believed to be climate change which caused changes in the environment that Neanderthals couldn’t adapt to.


[4] A new theory, however, from Pat Shipman, an adjunct professor of anthropology at Pennsylvania State University, is challenging this widespread belief. Her theory is that modern humans, who were still hunter/gatherers, were able to adapt to climate change because they had dogs. For some unknown reason, Neanderthals never established a relationship with canines. Dogs would have given early humans a huge advantage in locating and killing prey, guarding small villages, humans were close by. The cooperation between man and dog made hunting more efficient with less risk of being injured, and provided more food for people and dogs.


[5] Humans living with canines would have had advanced notice of danger, giving them time to react. Neanderthals hunted with hand weapons which meant they had to get close to kill prey, putting them at greater risk of being hurt or killed. If Shipman’s theory is correct, early dogs were already having an impact on human history.


[6] It’s an interesting theory and has some archaeological backing from research conducted by Mietje Germonpré from the paleontology department at the Royal Belgian Institute of Natural Sciences. She found evidence of large carnivores at huge collection sites of mammoth bones in Europe. Originally, the large carnivores were assumed to be wolves, but further study of the bones showed they were early domesticated dogs larger than modern canines.


[7] With one species of man extinct, human civilization began to evolve when modern humans transitioned from hunter/gatherers to an agricultural society around 10,000 or so years ago. Archaeological findings do suggest domesticated dogs were living alongside humans before they turned to farming, and both adapted together to a new way of life.


[8] Humans understood the benefits of their partnership with dogs when they discovered that canines were helpful with everyday tasks. They began to domesticate other animals including sheep around 11,000 to 9,000 BC and goats around 8,000 BC. Both animals were used for food and milk, and their coats had other uses. Pigs and cattle were domesticated about the same time. Horses weren’t domesticated until around 3,000 BC and were used for food and milk before humans discovered horses could be ridden. The horse gave humans the ability to move faster and farther. Oxen were domesticated about 4,000 BC which helped farmers increase production of wheat and rice and transport their crops over longer distances. The camel, llama and alpaca were domesticated around 3,000 to 1,500 BC.


[9] Taming other animals meant there was always a steady supply of meat and dairy when farmers were able to manage and herd livestock. This played a huge role in an emerging agricultural society which aided in the expansion of human civilization. Larger farms produced more food. Access to more food caused an increase in population that then needed infrastructure, a social pecking order, and architecture. Interactions between different civilizations grew as trade routes were established.


[10] The domestication of animals transformed human civilization and had a huge impact on the lives of people. It opened up the world to expansion, trade, and knowledge. However, it was the first domesticated animal– the dog– that helped humans understand it was possible to tame other animals. This realization changed human civilization and ushered in our modern society.