Related Articles

Below you'll find a collection of short, supplemental articles categorized by presenter. A more lengthy feature article is also available.

Robin Ian MacDonald Dunbar
Professor, Evolutionary Anthropology
Director, Institute of Cognitive & Evolutionary Anthropology
University of Oxford, United Kingdom
Co-Director of the British Academy’s Centenary Research Project
Lucy to Language: The Archaeology of the Social Brain

Imagine No Religion

Religions are only possible because of our social brain, says evolutionary anthropologist Robin Dunbar. Building on the work of others, Dunbar is currently looking into why religious beliefs are “so intense,” as he puts it. “What makes them like that?”

Although the work has just begun, patterns can already be seen in the data. “The eye-opening thing for me is that, on an individual basis, religion is actually a good thing for people,” he says. “It is clearly something that’s built into the human psyche generally and when it works it really works as a communal bonding mechanism.”

The problem, he says, is that religions are such powerful mechanisms that it’s very easy for political powers to co-opt them and to exploit them, particularly on a large scale. “With the marriage of church and state,” Dunbar continues, “you had this big transition from these small-scale community religions to world religions, some of which are extremely powerful today. Since the whole mechanism is based on ones that are designed to create this sense of them and us and this deep bonding within the community and deep protection of the community, it doesn’t take much to kick it off,” he says, “and that’s when the trouble comes.”

Dunbar’s Number

When it comes to our social circles, we top out, on average, at 150 people. That inner circle is in essence the first degree in the six degrees of separation Rolodex, says Robin Dunbar.

What that means is that within that group, we have the kind of social bonding where we call anyone in that “inner” circle of 150 people and ask them to meet us at the pub. “This circle of 150 persons turns out to be highly structured, so to draw a visual, it consists of a series of expanding circles that start with a small core around you of about five people, then goes up in multiples of threes, as it were, to 150,” he explains. “So these layers are five, 15, 50, 150.” What happens is in the inner core layers, the five and 15, there tends to be cohesion, but as you get further out to the outer layers, then you really are referring to friends of friends and distant relatives and their 150s only partially overlap with yours. “The key difference between the 150 and everything else is that 150 is the limit you know, in terms of persons, well enough for whom to give and from whom to expect favors. Outside the 150, you have to have labels or roles for people,” he says.

Reverse “small-world” experiments, wherein participants are asked to send a letter to some random person in the middle of nowhere, starting with someone you know, have shown that people generally start to run out of new people to ask for this initial favor at about 150 or so. “The big thing is the frequency of it,” says Dunbar. “As you go down through the circles from five out to 150, the frequency of interaction declines, so you see people less and less often. But the emotional intensity of the relationship also declines in very tight correlation. That’s how you get these small-world effects, because you can find Uncle Joe who you only see once a year at weddings or funerals, but you feel you can ask him to pass the letter on, because he’ll know someone else in his circles who’s much further away. Very quickly you’re covering virtually the whole planet.”

Theoretically, our circles of sociality go beyond 150 to 500 to 1500, and perhaps beyond. But, individually, we haven’t evolved to take on more yet, Dunbar says. “The trajectory has always been onward and upward in progressively bigger sizes of communities, but that has only been possible because of our brains evolving proportionally to allow us to handle it. We’re not quite sure what it is that underpins or constrains group size here— whether it’s purely cognitive or whether it is a time issue. In other words, to have a relationship with other people you would have to spend time with them—going to a baseball game or whatever you like doing together. But spending time with people is a very costly thing to do. If it’s a cognitive limit—we’re already living in much bigger communities now, such as in big cities. And it’s clear that they’re also rather dysfunctional, presumably because they are way beyond the real limits of the 150 with whom we can cope.”

Chances are better than good that we humans are not going to evolve a bigger brain in the timescale required to solve the global problems threatening our species now. “But,” Dunbar asks, “could we cut through it with more sophisticated electronic media? Is, for example, text messaging a route to creating bigger communities? Can Facebook, MySpace, and things like that be the way through this glass ceiling, allowing you to handle more information than you could on your own, or to use your time more efficiently to contact more people than you could do in everyday life on your own?”

The answer is?

“We don't know yet. We don’t know if these electronic media are actually allowing us to cut through this glass ceiling. It may actually just be a cognitive constraint and time may be less important.” But Dunbar is wanting to find out and is taking part in projects looking into just that—whether or not the new media the Internet has fostered might allow us to break through these constraints.

Marcus W. Feldman
Professor, Department of Biological Sciences
Director, Morrison Institute for Population and Resource Studies
Wohlford Professor, School of Humanities and Sciences
Stanford University

The Man-Ning Of China

In 1979, the People’s Republic of China instituted a one-child policy as a way of controlling population growth and alleviating various social and environmental problems. The policy is controversial both in and outside of China primarily because of the individual freedom issues it raises and because of the manner in which the policy has been implemented. And, truth told, there are still many citizens that continue to have more than one child, despite this policy.

Chinese government official Wu Jianmin said that the one-child policy would be reconsidered during the Chinese People’s Political Consultative Conference in March 2008; at that time, however, a representative of the National Population and Family Planning Commission of China said that the policy would remain in place for at least another decade.

With only one child allowed and with the preferred gender being male—as it is in the majority of countries around the world—stories abound of infanticide and young girls meeting with premature deaths. The desire for males remains deeply entrenched in most cultures and especially in rural China—and the implications of that are evolutionarily frightening.

“We’ve made a prediction, a mathematical and statistical prediction, about what will happen in China,” says Marcus Feldman, who has been studying the imbalance in sex ratio in China for several years. “Within 50 years, if they continue doing what they’re doing now, they will have 135 boys for every 100 girls. That’s a disaster, because they’ll be pressured for migration out of the country, there will be an increase in violence against women, an increase in sexually transmitted diseases, and a general breakdown in social order.”

But there is hope, Feldman says. The Chinese government’s Care for Girls program is a proactive attempt to intervene and change the son-preference culture.

Erasing Race

“We never talk about the Middle Eastern race, do we?” Marcus Feldman asks.

It’s an interesting factoid, to be sure. But it’s more than that. It’s an indication the term "race" isn’t really appropriate in any context that we use it, he says.

In fact, as Feldman sees it, race as we know it needs to be erased, thrown out as an uninformed descriptor of our genetic heritage. “These days, we can be more precise about genomics and identify people’s ancestry,” he says. “Our work shows that a much more appropriate term is ancestry group rather than race. It is a much more caring meaning, from a biological point of view.”

By analysis, the Middle East falls out as a separate ancestry group. “They have ancestry in three places—Europe, West Asia, and their own area, the Middle East,” informs Feldman. “So, postmigration, we can distinguish them more clearly than people who come from Africa or Europe and we can regard them as an ancestry group. The minority group that lives in northwest China—the Uyghur—a Muslim group with genetic links to China, Pakistan, and Europe, is another example of an ancestry group.

And so it goes. We started out in Africa and from there have taken off to all parts of the world, mixing up our genetics quite a bit. These days, we’re all part something and we’re more the same than different. “In biological terms, race is an antiquated term that has lost any scientific utility,” Feldman says. “We now need another term to describe the genomic clusters of people revealed by modern technology.”

Curtis Marean
Professor, Institute of Human Origins
School of Human Evolution & Social Change
Arizona State University at Tempe

Should Women Rule?

Science has shown that plant foods were traditionally collected by women in hunter-gatherer societies while the men hunted. “The reason women don’t hunt is because it’s too dangerous for the children and the children make too much noise,” explains Curtis Marean. “In hunter-gatherer societies, the premenopausal women almost always have a child with them, because they suckle until they are four to five years of age, and they simply can’t hunt for those reasons.”

The social order that emanated in these societies tended to be male-dominant, often depicted in politically incorrect images of cavemen conking the wife on the head and dragging her by the hair when she disobeyed. In Africa, however, where climates are tropical to warm temperate, the social order among hunters-gatherers, scientists now know, leaned toward being more egalitarian—and women often had more influence.

“Within these temperate zones in the Cape Floral Kingdom, the social order would be more egalitarian,” Marean says, “although that tends to break down when you get into colder climates.” Since modern humans evolved in Africa, though, this more egalitarian form of social order was likely the context for the origins of modern humans.

In these warmer climates men hunt to provide protein to the group, and this helps them buy into the social contract, and also display their “fitness” to attract a mate. “One way that men display their fitness is with hunting, so women evaluate the phenotypic, therefore genotypic fitness of men based upon their hunting abilities,” Marean says. In other words, he says, “a man who cannot see very well, who is physically weak, and not all that smart is not a good hunter.”

The research at Pinnacle Point shows that by 164,000 years ago, humans had expanded their diet to include shellfish. “But the thing about shellfish is they’re a collectible food source and women can collect shellfish,” Marean points out. That, he says, can change the economic contract between men and women.

With women producing protein through shellfish collection, the traditional system can break down and men at that point may need to do other things to document their fitness. In ecology, there is a theoretical literature called “costly signaling theory” and the idea is that men signal in costly ways to document their fitness—for humans this can include things like warfare, sports, and so on.”

Ethnographic and archaeological data show that once hunters-gatherers started exploiting shellfish, their group sizes often increased and they lowered their mobility. “That’s because the food availability has increased in its predictability and density,” Marean says. “Often along with that, warfare increases, because their food resources are predictable in time and space, and this makes food supplies more susceptible to raiding and stealing by men from others. So the use of coastal resources may stimulate greater amounts of conflict.”

The effects on social order from the use of coastal resources can have positive impacts as well. “When group sizes get larger and mobility decreases, social relations between people can become more complex, and individuals must use increasingly sophisticated means of mediating these relations, something at which women excel,” Marean says. “Symbolic behavior—such as ornaments, body painting, music and so on—are some ways this can be accomplished. Thus, these are good contexts to drive the evolution of the complex forms of cooperative behavior. It seems no surprise then that our discovery of early evidence for coastal living comes with very early use of pigments,” he adds.

Modern humans evolved sometime between 200,000 and 100,000 years ago, most likely during the long cold glacial stage that dominates that time. “The genetic record shows us that during this time the ancestral population for all modern humans was reduced to a very small group, hundreds to a thousand,” Marean notes. This small group of early humans faced an enormous environmental crisis that likely drove the evolution of our ability to cooperate, and put a premium on its use.

“Today, we are faced with an environmental crisis of enormous proportions and we all need to cooperate at the global level,” Marean says. “The alternative is that strong countries take from the weak. Cooperation seems to be a better way, but what is the pathway to getting us together?”

Our progenitors living way back when weathered a life-and-species-threatening environmental crisis. “They likely did this by finding ways to cooperate, and women were likely a key part of that,” suggests Marean. “Perhaps that provides us with a lesson for our future.”

Dig It!

When we think back to the romantic days of archaeology—in the 1930s and 1940s—we tend to conjure scenes of dig sites and scientists reminiscent of those depicted in Indiana Jones movies—dusty, barren landscapes or deep, dark caves where bronze-skinned, swashbuckling hunks of men, dressed in khaki brown cargo pants and shirts and topped off with pith helmets, extract dried bones and strange artifacts from hidden pockets in the Earth as the sweat glistens on their foreheads.

The digs then were just that—digs—and the archaeologists and paleoanthropologists of yore had only basic tool kits, equipped with shovels, pickaxes, chisels, and tape measures. Technology has changed all that.

“Field archaeology is very expensive these days and we dig very, very slowly,” says Curtis Marean. “Cave 13B at Pinnacle Point in South Africa threw us a lot of curve balls because of the very complicated stratigraphy. Ultimately, we got it all sorted out. But it all takes time,” he says.

The first reconnaissance Marean did was in 1999. The textbook-changing Nature paper was published in 2007. “It’s a long road,” he notes.

In an effort to streamline the journeys back in time, Marean and his team at Arizona State University have helped pioneer new ways of collecting data and in the field they’re on the cutting edge of methodology. “These days, everything is plotted piece by piece and we have very strict field collection protocols,” he says.

“We don’t even use tape measures,” Marean continues. “Every site we excavate has its finds measured with a total station, a laser transit. Basically, this is a surveying instrument that projects a pulsing laser that precisely measures its target, the same device surveyors—the guys out there in their yellow jackets—use on the highways and roads. We have very sophisticated laser transits that don’t need a prism, but can measure their target directly with millimeter accuracy. It’s military technology that is directly hooked up to computers for direct acquisition of data, which is then immediately brought into our geographic information system (GIS) on a laptop.

With the right tools on that laptop, the data can, in turn, be rendered in 3D—for full immersion. That means scientists will soon be able to take you to their sites without leaving the comforts of your own living room. “When we publish a paper, I want people—even a 10-year-old kid—to be able to log onto our Web site and fly into our cave and see our results in real time, and as we field-collect the data, it appears in real time on that Web site, so a visit almost becomes like a ‘second life’ kind of experience,” says Marean.

“Then, if the student wanted a deeper explanation or to know more, they could click on an avatar and the avatar would explain what was going on there. We could even have live situations where at certain times I would be there in that cave and they could ask questions. It shouldn’t be too long before we should be able to deliver this nearly seamlessly to the Web,” Marean says. “That’s my vision.”

Dig it!

Svante Pääbo
Molecular Biologist
Director, Department of Genetics
Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany

Pääbo's Thought Experiment

What if Neanderthals would have survived 30,000 more years, just another 2,000 generations or so, not that long—and been with us today?

If that seems preposterous, consider that the Neanderthals lived through several glaciations and managed to survive 300,000 to 400,000 years. Then consider this: that’s longer that we humans have been roaming the Earth.

As a thought experiment, Svante Pääbo suggests: contemplate how we would view ourselves in relationship to other organisms if we walked alongside Neanderthals.

“Would we have this absolute division between humans and animals, this dichotomy, that we have now if we had some other beings, which in some sense were truly different from us but still had some form of language, culture, and technology?”

Neanderthal Park?

Now that Svante Pääbo and his team are working to sequence the entire Neanderthal genome, is it possible they could actually clone a Neanderthal?

No, Pääbo says. “You would need an intact cell, a single cell where all the DNA would be,” he explains. “What we have are tiny fragments of genes, broken-down genes, modified and mixed in with lots of fragments of bacterial DNA.”

Dennis J. Stanford
Curator of Archaeology
Former Chairman, Anthropology Department
National Museum of Natural History, Smithsonian Institution

Migration: The Mystery within The Mystery

Why would our ancient ancestors have left a paradise in South Africa? Why would they have left Europe, setting off on an adventure that they must have known could kill them and surely took many of them en route to their destinations. “I’m always asked that,” says Dennis Stanford.

“You could explain the human migrations as an economic model, or an exploration model, or a spiritual model,” he says. “You have to remember that the people we’re trying to study were around long before Jesus Christ or Muhammad or even before any of those concepts came into view, and they operated in a reality that a white Anglo-Saxon Protestant male from Wyoming has difficulty understanding. That’s why you have to look at the spirituality of it, because the spirituality of it is indeed true, at least in their minds. That’s how they operated and therefore it worked for them, even though that reality is just a conception,” Stanford says.

“The bottom line is that the question of why they migrated is an almost impossible question to answer. We really have no idea and if we knew we likely wouldn’t believe it,” Stanford adds. “I use a true story of a group of Baffin Island Eskimos back in the 1870s as an example. Two spiritual leaders got into a violent discussion, which is pretty uncommon amongst that group of people, and one of them was killed. So there was a big confab within the whole group and they decided they had to split into two units, and the surviving elder had to leave along with the people who supported him,” he says.

Over the next five years, the banished group of Eskimos traveled and hunted and explored the high Arctic islands above Baffin looking for a proper homeland. “During the 1870s, the whaling fleets and the Northwest Passage people were sailing around that area of the world and they would encounter these people. The ship captains would camp with them and log in who they met and where they were, so we have a pretty good map of where these Eskimos were for about five years trying to settle into a new place,” Stanford points out.

“Here’s what happened though. The leader had an out-of-body experience one night,” Stanford goes on, continuing the story. “In the morning, the leader assembled the group and said, ‘Look, last night I journeyed and I met a band of Eskimos who live north of here. They are in desperate need of help and they would like us to join them. This is how we get to them.’ It was across the Davis Strait, some of worst water of the world, and up the west coast of Greenland.”

The banished band took that journey and when they arrived at the destination, “they indeed encountered the polar Eskimos who were barely making it. “Explain that,” says Stanford, “all because of an out-of-body experience.”

Where Am I Going and Why Am I in This Handbasket?: A Worst-Case Future Scenario

“The worst-case scenario is a bleak Blade Runner future and I am worried about that,” says Dennis Stanford. “I’ve worked with Eskimos and watched the Arctic for a long time and [as a result of global warming] the ice is melting faster underneath than scientists and geologists predicted and it’s going to be gone in a couple of years. Look at what’s left now—NASA has a Web page. It shows the difference between the last glacial maximum and today,” he says.

Earth scientists everywhere agree that climate change is under way and this is only the beginning. “The weather patterns and storm patterns are going to shift,” says Stanford. “The ocean conveyor belts are already shifting. The melted water from all those glaciers is going to end up someplace. Sea level will rise a meter or two. Malibu Beach may get flooded. It’s definitely going to clean up some stuff. The distribution of precipitation will shift and perhaps places that are deserts now might become productive farmlands. That may be a good deal, because we’ve kind of wiped out the Midwest and a lot of Europe has been over-farmed. It may be that new places will be developed. But then comes the political question of who’s going to live there and who’s got the big guns to take it over? We already know right now who’s got the big army and it ‘ain’t’ us. We’ve already used ours up.”

The one thing Stanford does predict is that human population will be "reduced,” as he puts it. “There’s no doubt about that in my mind. This planet doesn’t have the resources to handle the population we have now.”

A New World: A More Desirable Future Scenario

A positive possibility for the future is that we will get smarter and somehow find a way to reconnect with the environment. “I do hope the cerebral end of it expands, and there are some interesting things going on now,” says Smithsonian’s Dennis Stanford.

“There is a consciousness shift occurring, particularly with Native American spiritual leaders joining with spiritual leaders around the world,” he notes. “They’re saying now is the time to share knowledge and reacquaint ourselves with the natural environment. We need to learn that plants and animals are not property to be owned, but are ‘all our relations,’ as they have always viewed them.”

Viewing life from that perspective, Stanford says, allows you to truly appreciate it. “And it takes away the greed. The greed, what I see in politics and business and the military, all one and the same, is one of the most dangerous and important things we’ve got to address.”