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How Many Friends Does One Person Need?: Dunbar's Number And Other Evolutionary Quirks Hardcover – Mar 30 2010

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Product Details

  • Hardcover: 304 pages
  • Publisher: Faber & Faber (March 30 2010)
  • Language: English
  • ISBN-10: 0571253423
  • ISBN-13: 978-0571253425
  • Product Dimensions: 13.4 x 2.8 x 20.5 cm
  • Shipping Weight: 440 g
  • Average Customer Review: Be the first to review this item
  • Amazon Bestsellers Rank: #109,096 in Books (See Top 100 in Books)
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Product Description


An eclectic collection of essays on humanity and evolution with something for everyone. Dunbar explains, among other things, why monogamists need big brains, why it is worth buying a new suit for an interview, how to interpret an advert in a lonely hearts column, the perils of messing with evolution and, of course, how many friends one person needs (150 as it happens, aka "Dunbar's number"). He speaks with authority and seduces us as only a master storyteller can.
--Kate Douglas, New Scientist

Lucid and provocative.
--Bryce Christensen (Booklist 2010-11-01)

Entertaining and informative...Covering an impressive breadth of topics and disciplines, Dunbar explores the ways in which our brains control every aspect of our social lives (surprise, we are less complicated than we think). Our needs, preferences, and commonalities are a function of what--not who--we are...Full of interesting facts and Dunbar's winning personality, his effort reads like a fascinating lecture that most readers would be all-too-happy to attend. (Publishers Weekly (starred review) 2011-01-24)

[A] fascinating volume that ranges widely across time, space and human practices...Tossing off light-hearted examinations of such fairly innocent topics as why we kiss and why all babies look very much alike, Dunbar is unafraid to tackle sensitive and controversial issues as well. These essays deal with race, gender, intelligence, class, and nationality in dispassionate and unflinching ways that do not seek to cushion hard facts with mealy-mouthed sanctimony...Far from being a catalogue of gloom and doom, this book leaves the reader marvelling at how far homo sapiens has come, and how far we might yet ascend.
--Paul Di Filippo (Barnes & Noble Review 2011-03-03)

For the past thirty years [Dunbar] has conducted research designed to uncover the workings of our ancestral hardware: to decode the scripts that drive much of our behavior and make us what we are as a species. Although Dunbar emphasizes the value of kin, he is anything but a sentimentalist. In this book, he chases after averages and patterns, after predictive links between current behavioral and physical traits and what, in the Pleistocene or Neolithic past, would most likely have been mating or survival advantages...In general, understanding the Darwinian back-story of our species is arguably a way to short-circuit the infelicities of our gut responses: a way to combat gut-level racism, sexism, beauty/symmetry biases, height biases, ageism, and the many variants of tribalism and jingoism...Dunbar shows that, if we go far enough back in our family trees, we are all the product of a tangled skein of heroes and villains, of conquering populations and conquered ones, of dominant and minority races, of in-groups and out-groups. Whether we as individuals call ourselves one or the other is often just a matter of how far back in time we set our stakes combined with the limits of our instruments for probing ourselves. Knowledge such as this may well be the only way out of the ancestral cave.
--Michele Pridmore-Brown (Los Angeles Review of Books 2011-05-24)

It is an entertaining as well as informative read.
--Rosalie West (Portland Book Review 2011-06-01) --This text refers to an alternate Hardcover edition.

About the Author

Robin Dunbar is currently Professor of Evolutionary Anthropology at Oxford University and a Fellow of Magdalen College. His principal research interest is the evolution of sociality. He was elected a Fellow of the British Academy in 1998. His books include The Trouble with Science, 'an eloquent riposte to the anti-science lobby' (Sunday Times), and Grooming, Gossip and the Evolution of Language. The Human Story was described as 'fizzing with recent research and new theories' in the Sunday Times and 'punchy and provocative' by the New Scientist. How Many Friends Does One Person Need?: Dunbar's Number and Other Evolutionary Quirks was published in 2010.

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Most Helpful Customer Reviews on (beta) HASH(0x9db24cc0) out of 5 stars 14 reviews
15 of 15 people found the following review helpful
HASH(0x9db4803c) out of 5 stars Provocative short course in anthropology Dec 25 2010
By Ursiform - Published on
Format: Kindle Edition
I first encountered Robin Dunbar with his excellent book* "Grooming, Gossip, and the Evolution of Language", where he put forth the theory that gossip replaced grooming as we evolved from ape to human, thus allowing larger social groups to form. (This, in fact, is the topic that inspired the title of the current book. His answer is about 150, "Dunbar's Number".)

This book is a collection of previously published articles which have been updated for the book. As such, it doesn't have a strong, integrating theme. But it does provide a series of provocative insights into why we are as we are. Dunbar explains how our evolution has shaped how we are, what traits we share with the great apes and where we have surpassed them, and why we act as we do.

In a lively skip through many topics, Dunbar covers topics like why gossip is good, why we like presidential candidates who are tall and have symmetrical faces, and why kissing may be an adaptation for choosing mates with desirable immune systems. (Yes, really.) He even considers why humans are such religious critters. All-in-all, a highly engaging and thought-provoking book.

* Grooming, Gossip, and the Evolution of Language
31 of 36 people found the following review helpful
HASH(0x9db48090) out of 5 stars Interesting, but flawed. Jan. 16 2011
By Wayne Robinson - Published on
Format: Hardcover Verified Purchase
I thought it was a very good book. I found it very enjoyable to read. I also thought that it provides a lot to think about.

However, I didn't give it 4 or even 5 stars, because it has major flaws.

For one thing, at least in the Kindle edition, the author doesn't cite any references.

More seriously, a lot of the author's statements are just wrong.

For example:

In chapter 10 'The Darwin Wars', it's stated, "Chris Organ from Harvard University and his colleagues carried out the first successful extraction of DNA from a 65 million year old Tyrannosaurus rex ..." Well, no actually, it was collagen protein. DNA is so fragile that around 100,000 years remains its limit for recovery. The only reference to dinosaur DNA and Chris Organ I can find is his observation that the lacunae in fossil T rex bone (which previously contained the bone cells, osteocytes, are smaller, so therefore the osteocytes were smaller, so therefore the nuclei were smaller, so therefore the genomes were smaller (with less 'junk' DNA)-like contemporary birds (there might be one or two 'therefores' too many).

In the very same chapter, it's stated, discussing Kennewick Man the 9,000 year old remains found in Washington state, "There is now compelling evidence to suggest that the earliest inhabitants of North America did in fact come from Europe (the vicinity of Spain, as it happens)" sometime around 20,000 years ago". Again no; extraordinary claims (humans managed to cross the Atlantic, in a glaciation, and then crossed the entire North American continent?) need extraordinary proof. The alternate interpretation that Kennewick Man more closely resembles the Ainu of northern Japan and came from there is more plausible.

In chapter 5 'The Ancestors That Still Haunt Us', in a discussion about Indo-European languages, it's stated " ... Finnish and Hungarian, both of which derive from the invasions by Mongolian peoples, the latter most famously associated with Attila the Hun and his chums". Again no; Hungarian (and Finnish and Estonian) are derived from an Ugric language of western Siberia 3,000 years ago. Nomads, but not Mongolian.

The book would have been considerably improved if someone else had read it before publication and checked the 'facts'. The errors don't damage the authors arguments seriously, but I'd advise that I'd check any 'facts' proffered before using them, particularly if they seem difficult to believe.
15 of 16 people found the following review helpful
HASH(0x9db483fc) out of 5 stars An enjoyable book, albeit a bit lacking in depth April 24 2010
By M. Moran - Published on
Format: Hardcover
This is a collection of previous material from New Scientist, The Scotsman, and other periodicals. Stylistically, this makes it quite repetitive. For example, he says several times within a few pages that babies are born "wildly premature". A little more tight editing would make it feel like a cohesive whole.

What I find more grating is how he continually speaks as if our ancestors, and their genes, had changed behaviour based on knowledge of future hardship:

"... their descendants decided to increase the size of their brains dramatically ... The inspired solution our ancestors eventually came up with was ..."

Maybe I'm going a bit Dawkins, but this is not how it works. I know Dunbar doesn't think anything other than evolution is involved here, but it'd be far better if his wording reflected this. I know this is hard to do, and I struggle now to think of an alternate wording, but the assignment of intentionality should be avoided if possible.

Factually, it raises itself above a lazy New Scientist article by delivering an occasional nugget of information you wouldn't often see. For example, men have only one X chromosome meaning they have a heightened chance of colour vision defects arising from mutations, compared to women who have two X chromosomes and hence a backup copy. This also means that mutations in one X chromosome can lead to extra receptor types in women. In a very real way, women may see differently than men. I don't buy his followup argument that this is why women are supposedly more colour conscious than men. Still this is populist science, and a nice hook.

I've previously read Dunbar's The Human Story, and wrt Dunbar's Number this book is mostly a recap. Back then 150 didn't have a name, but it did have a reasoned argument behind it. A little of that is repeated here, but without the useful explanatory graphs (that seem so anathema to science in public today).

He drops in a bit of irrelevant numerology in as well: he claims something special about the scaling of three which relates the respective size of shells of friendship groups (people you choose to see daily/weekly/monthly/yearly). This could just be happenstance. Similarly, there are some interesting examples of where groups of 150 people appear in modern life. However, if you go looking for numbers, you will find them. I'd like some more concrete examples backed up by reasoning, not just anecdotal evidence.

Overall, it's an enjoyable book, albeit a bit lacking in depth. If you are really interested in some more tighter arguments (with graphs!) then I'd recommend his previous book, "The Human Story".
8 of 8 people found the following review helpful
HASH(0x9db4890c) out of 5 stars The Answer is "150"--And, for a Change, Not "42" March 7 2010
By William Holmes - Published on
Format: Hardcover Verified Purchase
Robin Dunbar, Professor of Evolutionary Anthropology at Oxford University, offers a fascinating collection of essays about the evolution of humans and human society. The answer to the book's title, "How Many Friends Does One Person Need?", is somewhere around 150 (Dunbar's Number). From groups of hunter-gatherers to well-run corporations and armies, the number 150 is a basic (and maximum) building block for human organizations. Groups with fewer than 150 individuals can generally function on a first name basis--members can actually know, to one degree or another, everyone in the group. Groups larger than 150 tend to exceed the capacity of individual members to keep track of social complexity, which means that, like large corporate enterprises, they need heirarchy and management to preserve manageable group structures.

According to Dunbar, the complexity of human society--not tools, or walking upright, or hunting--it the primary force driving the growth of the human brain. Our brains enable us to speak and sing and otherwise communicate with each other without actually touching, so we can groom each other at a distance, so to speak. Because our social interactions don't require one-on-one contact, human groups can be larger than the groups of our primate cousins--but group size still has a limit, which appears to be about 150.

Dunbar's book is very readable and is filled with fascinating tidbits, like the fact that all human infants (even the ones who are carried to a full nine month term) are born premature. For our children to be born at the same level of development as, say, a chimpanzee, the gestation period would need to be about 22 months. Human children are born prematurely and require a great deal of parental care because that it the balance evolution has struck between large brain size, the woman's pelvis, and the woman's ability to walk upright. The relative helplessness of human infants puts an additional premium on pair bonding, communication and group support, thus driving a feedback loop rewarding bigger and more social brains.

Dunbar tackles a number of other intriguing questions about human behavior, including why are we often, but not always, monogomous? From which single conqueror are more than 8.5% of the men in Asia now descended? Why is gossip important? This book is an easy one to pick up and keep at, with each chapter drawing the reader in with yet another insight about the quirks that make us human. I highly recommend this book, along with Dubar's equally fascinating The Human Story.
2 of 2 people found the following review helpful
HASH(0x9db481e0) out of 5 stars Some new things, but mostly a good, funny collection of essays on evolution Dec 31 2013
By Souvik Mitra - Published on
Format: Kindle Edition Verified Purchase
I had a good time reading this book. It's funny & builds on stories & research. It pokes you by relating all that science to things like gossip & culture. And then throws in some religion, God & morality. It gets didactic on exercise, & endearing on familial bonds. And why polygamy is know. The only juicy topic to miss out perhaps was an evolutionary angle to alcoholism or substance abuse.

So yes, the chapter on number of friends is certainly new. Though I'm sure I've read a business book that talked about this company which always broke itself up when it reached a certain manpower. My point is, it is all very enjoyable & fast, but I would not go so far as saying that this is new stuff. It is a decent read for folks who read science otherwise - a sort of a refresher on evolution. For those that are not that much into popular science reading - it is a good collection of essays on evolution, albeit slightly random.

Whether you read this book or not would not matter much anyway. I would say that you should read it. May be.