Human Evolution: Our Brains and Behavior

Robin Dunbar presents a marvelous new perspective on how humans evolved as social animals. But as an evolutionary psychologist, his perspective is limited by his poor understanding of what humans actually do within their social groups. To learn more about that, I strongly recommend to the reader that this book be read in conjunction with the book, Moral Origins, by the anthropologist Christopher Boehm. Moral Origins: The Evolution of Virtue, Altruism, and Shame

Very easy to read and replete with ideas about human psychological evolution. Having said that I have to admit that I find Dunbar's videos more entertaining. I also am not sure what I think about the rather larger than normal fon though it did ease the reading in lower light levels.

I am on Chapter 4 so my comments are premature.I have enjoyed the book so far because it gives me new insights from an unfamiliar science.I believe, Robin Dunbar's hypothesis is correct. Ideally we need to be involved with about 150 other people to obtain the necessary information+motivation to evolve.

I am a long time fan of Dunbar's, back to his  Grooming, Gossip, and the Evolution of Language , where he showed that there was a relationship between neocortex size in primates and the size of the groups they lived in, that that relationship implied that humans should have a group size of about 150, that many lines of evidence supported a group size of about 150, and he then posited that humans could maintain such a large group size because language, and "gossiping", had replaced (normal primate) grooming in binding people together.He has since been responsible for many more interesting ideas about human evolution. This book brings many of those ideas into a possible scenario of many millions of years of evolution. There is, as the author acknowledges up front, a fair amount of speculation involved in his scenario. He also acknowledges that future discoveries may forces changes in the story. But it is a well argued story, and one that invites contemplation as well as offering the opportunity to throw stones at it, although stones with facts attached are much to be preferred.Dunbar explicitly chooses to go beyond the "stones and bones" of conventional paleaoanthropology, looking for inferences that can be drawn from how lifestyles of the range of existing primates can be used to constrain or inform the options for how human ancestors may have lived.He begins with the common and reasonable assumption that the common ancestor between humans and chimps was generally chimp-like. He then identifies and tries to explain a series of transformations that lead from there to us. In the process he identifies five transformations, beginning with bipedalism and concluding with living in large groups reliant on agriculture.One key concept he uses is time budgets. There are only 24 hours in the day. Primates generally rest at night (owing to poor night vision and predators). In the tropics they also rest mid day due to the heat; how long depends on their size and corresponding heat load. In the remaining hours they need to find enough food (including travel time to feeding sites), and to groom each other to maintain cohesion.The feeding and travel time can be estimated based on individual size and brain size (brains being big energy hogs), group size, whether the group feeds as a whole or breaks up and regroups, food type, and food density in the environment. Dunbar relies on what we know about existing primates living in various group sizes and environments coupled with what we know from the stones and bones to estimate food needs at different evolutionary times.Grooming time he estimates from observed primate grooming and from group size, which can be estimated based on brain size (as braincases don't provide a direct measurement of neocortex size).Put it all together and he finds time deficits at different stages of ancestral evolution, then sets out to understand how the deficits could have been closed through changes in behavior or diet. For example, he posits that the development of laughter, then singing, and finally full-blown language and storytelling improved the time efficiency of "grooming" by allowing multiple people to interact at once, rather than being a one-on-one activity like physical grooming. Similarly, the use of roots, the use of tools, and finally the use of fire improved food collection and processing, allowing more efficient use of the time spent eating. The processing of food before eating it also allowed the evolution of a gut that required less energy for digesting food, thus reducing the need to find and eat as much.On the issue of fire he references another book I particularly like, Wrangham's  Catching Fire: How Cooking Made Us Human . Dunbar disagrees with Wrangham, however, on when ancestral humans routinely controlled and cooked with fire. He finds no need for it as early (more than a million years ago) as Wrangham posits, instead believing its use became routine only about a half million year ago. At that point there is clear evidence of routine fire use, Homo had developed a much larger brain which would explain the ability to control fire, and cooking would be needed to close the time budget. Including the need, by the way, to now make time to gather wood and maintain the fire! Going beyond cooking, Dunbar suggests that the use of fire also increased the useful hours in the day by extending the time with light into the night. With the development of modern language capability he speculates that storytelling around the campfire, as it were, was another advance in "grooming", using re-purposed nighttime to allow the social activity required for modern human sized groups. (He also discusses the quality of language Neanderthals and other humans of their time would have had.)There are lots of theories (and books) out there claiming this or that drove human evolution. Dunbar argues that it wasn't one thing, it was many things interacting with each other, and playing out in a series of steps, that led from a chimp-like ancestor to creatures that can read and write books. He examines each step based on stones and bones as well as what the wide range of existing primates tell us. He tries to work out the sets of changes that best explain each step, avoiding unlikely leaps of evolution, advances not needed to survive in the environment, and deus ex machina solutions. He acknowledges uncertainty, as a good scientist should. The result is a great story that might even be true, and is very likely true at least in parts. Sure, it should be read with a grain of salt. But it should be read. There is a wealth of information in this book, and I don't know of anyone who has presented a more compelling theory of human evolution. As more is learned, the story of our evolution will evolve, but I doubt the day will come when someone picks up this book and thinks "boy did he get it all wrong!".I was provided a copy for review by the publisher, but have ordered a copy of the final version for my library. This one's a keeper!

Although this book was not what I expected, I enjoyed it nonetheless. I was expecting another book on paleontology or DNA to explain evolution. This book however focused on evolutionary psychology and anthropology. The information is well-explained and clear. No biology background is required to enjoy the book. I am not in a position to say whether the conclusions that Robin Dunbar reaches are correct, but based on the data he presents, they seem to make sense. I enjoyed his writing style and I found the book hard to put down. I recommend this book for anyone interested in human evolution.Disclosure: I received a complimentary copy of this book via Netgalley for review purposes.

This is a curious book. The author is well-known and knowledgeable, but the discussion often rambles and arrives at no conclusions. The focus on time management, while important, is extended far beyond what is justifiable: when you are in societies where bonding is managed by complex alternative arrangements, what is the point of computing how much time you would waste if you had to groom all the folks you liked? You don't. If you change your hunting and gathering approaches you have to know what those are to evaluate how much time they take. For example, he notes that Neanderthals appear to have hunted whatever was around where they lived: from huge mammoths to small birds. These involve different strategies and approaches to identifying prey, making kills, and using the resulting catch, and thus will have different impacts on time budgets, which are unlikely to resemble the time chimpanzees spend hunting for fruit: but not a word in the book about such issues.Also not a word is devoted to the fantastically vital capability of preserving information within a society. For example, there is no gene for fire starting: it's a skill that someone had to figure out and then teach to others. But you won't find any consideration of that issue here: fire just magically appears to reduce feeding time burdens 400,000 years ago. In similar fashion, the author dismisses the invention of agriculture, permanent housing, walls, and so on as trivial, even though, for example, Jared Diamond (Guns, Germs, and Steel) has shown that many key inventions in human society only happen a handful of times or even just once, and the whole human world is dependent on borrowing those ideas. Dunbar presents some experimental results showing that the first function of language is to transfer social information, but then fails to even address how other information is to be preserved. (The answer, of course, is visual learning. Humans teach each other in ways chimpanzees do not. Why is this not important?)If you are looking for an overview of the current state of the field, I recommend "A Pocket History of Human Evolution" by S. Condemi and F. Savatier, from 2019, which also contains lots of very recent interesting developments in the fossil and genetic records. Dunbar's book is certainly worth reading but only in the larger context.

Robin Dunbar’s writing is as genial as himself, but he doesn’t patronise. The non-standard larger print was an unexpected bonus given that most academic books need a magnifying glass but the statistics require a bit of work.

Excellent.