Shorter Not Taller and Our Brains Are Shrinking

[Faline]

People have got shorter and our brains have shrunk - and scientists believe farming could be to blame.
Modern humans are about ten per cent smaller and shorter than our hunter-gatherer ancestors, scientists have found, and our brains have fallen in size by the same proportion.
Most of that decline in physical size has occurred since the advent of farming about 10,000 years ago.

The findings run contrary to the popular notion that humans are growing progressively larger and taller.
Research shows that declines in height occurred in 19 of 21 societies that switched from hunter-gathering to farming - perhaps the greatest change in lifestyle in human history.

The findings pose a puzzle since societies that switch to farming usually experience a population boom as food becomes more plentiful.
Decline in stature is a phenomenon more commonly linked to food shortages and malnutrition.
Amanda Mummert, an anthropologist at Emory University in Atlanta, Georgia, suggests the drop in heights could be linked to a shortage of micro-nutrients as human diets took in less variety.


Although calories were abundant, the vitamins and minerals essential to growth - and which are only gained through a varied diet - may have become less common in people's diets.
One example of such a change was in China, where early farmers relied on cereals like buckwheat, maize and rice - all of which lack niacin, a vital nutrient for growth.
'This counter-intuitive increase in nutritional diseases resulted from seasonal hunger, reliance on single crops deficient in essential nutrients, crop blights, social inequalities and trade,' she told the Sunday Times.
Systematic studies of fossilised human remains found across Africa, Europe and Asia seem to back up Miss Mummert's findings.

Six different views of a 160,000-year-old human skull of an adult male from Ethiopia:


According to Dr Marta Lahr, co-director of Cambridge University's Leverhulme Centre for Human Evolutionary Studies, when human beings first emerged, around 200,000 years ago, they were tall and muscular.
The earliest human remains yet discovered date back to this time, and were found in Ethiopia.
According to Dr Lahr, these people had cranial features similar to modern humans, but were significantly larger and more robust.
Human fossil evidence over the next 190,000 years is patchy and incomplete, but it shows that humans remained tall and robust even as human culture began to emerge, as shown by the appearance of tools, weapons, needles and even musical instruments.
This size was maintained until about 10,000 years ago - the time of the advent of farming - when many populations began to show reductions in stature - and brain size.
But other researchers are less certain about the role agriculture has played in shrinking human proportions.
Chris Stringer, professor of human origins at the Natural History Museum in London, concedes that early humans had bigger bodies and brains than modern people.
'Some of this must be down to the demands of a Palaeolithic lifestyle in terms of a strong-muscled skeleton on the one hand, and the shielding effect of cultural innovations and a more sedentary lifestyle on the other, but it is unclear whether that is the whole story,' he told the Times.

The height difference between early and modern humans may even out, as improved nutrition in recent decades seems to be leading to a sharp increase in people's weight and height.
But even if agriculture were the reason why modern humans are smaller than our forebears, it would not solve the puzzle of why brains have also shrunk.
The Homo sapiens with the biggest brains lived 20,000 to 30,000 years ago in Europe.
Known as Cro-Magnons, they were tall with barrel chests and large jaws. Their brains had an average volume of 1,500cc.
These days, the male human brain averages 1,350cc, a decrease equivalent in volume to a tennis ball. Female brains have shrunk by about the same proportion.
Dr Lahr thinks that part of the answer may lie in improving efficiency - brain function commands about a quarter of all the energy used by the body.
Like advances in silicon chip technology, huge energy savings can be made by getting the same work out of less equipment.
'We may have smaller brains than early humans but it doesn't mean we are less intelligent,' she said.

[Viking64]

Interesting stuff, Kel! I have always thought humans on average were getting larger because so many things from the past, like mummies, suits of armour and old clothing from the 1800's looked so small. Great post.

[rottenflesh]

Interesting theory.

[candymosh]

[švabo]

I always thought we are getting taller coz of my height, 6.5

[kellyhound]

Also evolution as humans these days spend more time sitting at the comp or on a chair at work instead of hunting for food so we don't need to be robust and tall.
Maybe we develop an extra finger one day so mouse clicking goes faster )

[güttsfükk]

post sources !!! scientific posts are useless without a valid source

[Faline]

All i can find is the article pages, nothing from the actual university.

http://www.dailymail.co.uk/sciencete...=feeds-newsxml

http://www.azadnegar.com/article/wer...-farming-blame

[Faline]

1. Philosophical Transactions of the Royal Society of London, Series B, Biological Sciences. 2011 Apr 12;366(1567):1080-9.

The evolution of the diversity of cultures.

Foley RA, Lahr MM.

Leverhulme Centre for Human Evolutionary Studies, University of Cambridge,
Cambridge, UK. raf10@cam.ac.uk

The abundant evidence that Homo sapiens evolved in Africa within the past 200,000
years, and dispersed across the world only within the past 100,000 years,
provides us with a strong framework in which to consider the evolution of human
diversity. While there is evidence that the human capacity for culture has a
deeper history, going beyond the origin of the hominin clade, the tendency for
humans to form cultures as part of being distinct communities and populations
changed markedly with the evolution of H. sapiens. In this paper, we investigate
'cultures' as opposed to 'culture', and the question of how and why, compared to
biological diversity, human communities and populations are so culturally
diverse. We consider the way in which the diversity of human cultures has
developed since 100,000 years ago, and how its rate was subject to environmental
factors. We argue that the causes of this diversity lie in the distribution of
resources and the way in which human communities reproduce over several
generations, leading to fissioning of kin groups. We discuss the consequences of
boundary formation through culture in their broader ecological and evolutionary
contexts.


PMCID: PMC3049104 [Available on 2012/4/12]
PMID: 21357230 [PubMed - in process]

http://www.ncbi.nlm.nih.gov/pubmed/21357230

http://www.ncbi.nlm.nih.gov/pubmed?t...anda%20mummert

[Andria]

Overpopulation could be a factor too, with people evolving to be smaller due to crowding and depletion of resources.