Archive for the 'News' Category

By Christopher Stringer via Edge

I’m thinking a lot about species concepts as applied to humans, about the “Out of Africa” model, and also looking back into Africa itself. I think the idea that modern humans originated in Africa is still a sound concept. Behaviorally and physically, we began our story there, but I’ve come around to thinking that it wasn’t a simple origin. Twenty years ago, I would have argued that our species evolved in one place, maybe in East Africa or South Africa. There was a period of time in just one place where a small population of humans became modern, physically and behaviourally. Isolated and perhaps stressed by climate change, this drove a rapid and punctuational origin for our species. Now I don’t think it was that simple, either within or outside of Africa.

[CHRISTOPHER STRINGER:] At the moment, I’m looking again at the whole question of a recent African origin for modern humans—the leading idea over the last 20 years. This argues  that we had a recent African origin, that we came out of Africa, and that we replaced all of the other human forms that were outside of Africa. But we’re having to re-evaluate that now because genetic data suggest that the modern humans who came out of Africa about 60,000 years ago probably interbred with Neanderthals, first of all, and then some of them later on interbred with another group of people called the Denisovans, over in south eastern Asia.

If this is so, then we are not purely of recent African origin. We’re mostly of recent African origin, but there was contact with these other so-called species. We’re having to re-evaluate the Out-of-Africa theory, and we’re having to re-evaluate the species concepts we apply, because in one view of thinking, species should be self-contained units. They don’t interbreed with other species. However, for me, the whole idea of Neanderthals as a different species is really a recognition of their separate evolutionary history—the fact that we can show that they evolved through time in a particular direction, distinct from modern humans, and they separated maybe 400,000 years ago from our lineage. And morphologically we can distinguish a relatively complete Neanderthal fossil from any recent human.  More…

From Eric Michael Johnson at Scientific American, The Primate Diaries…

Let’s face it, as a species we’re obsessed with ourselves. The vast majority of us spend our days at work or school where a considerable amount of time is taken up not discussing the important issues of the day, but rather the juicy details of one another’s personal lives. Then we go home only to sign on to social network services like Facebook, Twitter, or Google+ and continue where we left off. In this respect we’re fairly typical primates. Most of our simian relatives, particularly our great ape cousins the chimpanzees and bonobos, like nothing better than keeping a watchful eye on what other members of their troop are up to. But our species has taken this preoccupation one step further.

Human beings are the most social of the primates and have the largest group sizes of any species in our order. For about 90% of our existence we lived in hunter-gatherer societies with populations that likely clustered around 150-200 individuals. By way of comparison, baboons come in a distant second with an average of about 50 group members. Now, thanks to modern industrial agriculture, our species has pushed that range well into the millions, a development that has resulted in considerable stress on our slightly above average primate brains. Of course, all organisms need to successfully predict and navigate their environments in order to relay their genes on to the next generation. It’s just that this becomes increasingly complicated when there are many individuals all interacting in the same environment simultaneously. Merely keeping track of these relationships requires a considerable amount of time and energy, not to mention brain power. More…

Photo by juliejordanscott on flickr

From physorg.com

Parents are often amazed by the speed at which children acquire language in early childhood, becoming fluent around three years of age. Compare this with the average adult attempting to acquire a second language, and it’s a quite remarkable achievement.

A five-year research project led by Professor Ian Roberts from the University of Cambridge aims to work out what it is about how a language is built that guides a child’s innate ability to acquire it.

In the late 1950s, the American linguist Noam Chomsky suggested that children are born with an innate ability to acquire language – a ‘blueprint’ for speaking any language on the planet. According to Chomsky, encoded in the human brain is an innate set of linguistic principles he called the ‘universal grammar’ that encompasses all of the properties that any language can have. The language the child then actually speaks is simply determined by exposure to the language (or languages in the case of a multilingual family) they hear as they develop.

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From physorg.com

Did you take a deep breath before pushing and shoving your way into a crowded train this morning? Stepped on a few toes or nerves perhaps? Phew, well, if you thought dodging elbows and trying to hop on that crowded morning rush hour train was bad, try thinking about this – the world’s population recently hit 7 billion and in an already crowded planet, that poses quite a problem.

According to the United Nations Population Fund, the world’s population more than doubled just in the last fifty years. This staggering growth is certainly a cause for alarm and has scientists, economists and sociologists scrambling to find a solution to combat the problems that come with an overcrowded planet.

Though some have hailed this as a milestone for humanity, there are probably many more reasons to fear our population boom than cheer it.

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From Lin Edwards, Physorg.com

The researchers, led by Jerome Sallet of Oxford University, said the results of the new study bear some similarities to research by other groups working with humans, that related brain size to the extent of social interactions. These studies include recent work that suggested a link between the volume of some regions of the brain and the number of online friends people have in social networking sites such as Facebook.

The new study observed 23 macaques in a number of groups of different sizes. The monkeys were kept in their groups for an average of over a year, and a minimum of two months. One monkey was alone in its cage, but in all the other groups, which had from two to seven individuals, a heirarchy developed in which an individual’s rank depended on the monkey’s ability to form successful social interactions, such as friendships and partnerships.

The study used magnetic resonance imaging (MRI) to compare the brains of the monkeys, and the results showed that in the temporal areas of the brain associated with social interaction skills, around a five percent increase in the volume of gray matter was found for each additional group member. The regions of the brain that increased in volume included the temporal pole, temporal cortex, and the inferior and rostral temporal gyri.

The researchers also compared the brains of male monkeys at various levels in the dominance-based heirarchy and found a number of brain areas, particularly the prefrontal cortex and inferior temporal sulcus, were enlarged in males of higher rank.

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