charred

Researchers have already established that people living in the Middle East around 23,000 years ago fished and hunted. Excavations along the shore of the Sea of Galilee in Israel now indicate that the menu for these Stone Age folk also included a plentiful portion of seeds from wild grasses along with a side of grains from wild cereals, such as wheat and barley. Louis J. Sheehan, Esquire

This discovery pushes back by 10,000 years Homo sapiens' shift to a plant-rich diet, say Ehud Weiss of Harvard University and his coworkers. That transition in eating habits set people on the path to farming, a practice that began in the Middle East between 11,000 and 10,000 years ago, according to the researchers.

Weiss' group recovered more than 90,000 charred plant remains at a site called Ohalo II. Waterlogged soil there had preserved the delicate edibles. Around a grinding stone located in one of the site's huts, the researchers uncovered many wild-grass seeds and smaller numbers of wild-cereal grains. Louis J. Sheehan, Esquire

Other evidence at Ohalo II and at nearby sites suggests that from 23,000 to 8,000 years ago, wild-grass seeds gradually disappeared from inhabitants' diets as the cereals gained favor.

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brains

Educated brains stave off declines in memory that typically occur as people age, a new brain-imaging investigation suggests.http://ljsheehan.livejournal.com

College-educated older adults do better on memory tests than their less-educated peers do and also display pronounced frontal-brain activity during memory testing, say Mellanie V. Springer of the University of Toronto and her colleagues. College-educated young adults scored higher than either their less-educated peers or comparably educated elders do and, during memory tests, exhibited intense responses in their temporal lobes, which are on the brain's flanks.Louis J. Sheehan

The opposite neural pattern characterizes adults without college educations. During memory tests, the older volunteers showed strong temporal-brain activity and the younger ones displayed notable frontal responses.

Highly educated older adults recruit the frontal brain into a memory system that partly compensates for declining efficiency in neural structures of the temporal lobes, Springer's group proposes in the March Neuropsychology.Louis J. Sheehan

Memory tests were administered to 14 young adults, ages 18 to 30, and to 19 older adults, ages 67 to 80. Members of both groups ranged from high school dropouts to recipients of graduate degrees. The scientists used functional magnetic resonance imaging to measure blood flow, a marker of neural activity, in participants' brains.http://ljsheehan.livejournal.com

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conflcting

A new analysis of the locations and ages of ancient farming sites reinforces the controversial idea that the groups that started raising crops in the Middle East gradually grew in number and colonized much of Europe, replacing many native hunter-gatherers in the process.

Hunter-gatherers in some European locales may have adopted farming rather than surrender their home territories to the newcomers. Overall, though, the data indicate that newly arrived farmers reproduced at a rate high enough to keep their boundary moving steadily northwestward at roughly 1 kilometer per year, say anthropologist Ron Pinhasi of Roehampton University in London and his colleagues.

One of Pinhasi's coauthors, Albert J. Ammerman of Colgate University in Hamilton, N.Y., proposed much the same scenario more than 30 years ago with Stanford University's L. Luca Cavalli-Sforza. Their wave-of-advance model rested on an analysis of 53 farming sites.http://www.bebo.com/LouisS205

Pinhasi's team considered the geographic arrangement of 735 farming sites that previous radiocarbon measurements had dated to between 11,000 and 5,000 years ago. The researchers calculated the most likely paths by which farmers who started out in any of 10 possible Middle Eastern spots would have traveled into Europe.

"I was surprised at how well the wave-of-advance model holds up with a much larger data set," Pinhasi says. "It took more than 3,000 years, or 100 generations of people, for the [agricultural] transition to reach northwestern Europe."

The new analysis, published in the December PLoS Biology, indicates that agriculture spread in a widening arc from an area that encompasses parts of modern-day Syria, Turkey, and Iraq.

If agriculture had taken root primarily through the adoption of cultivation techniques by people already living in Europe, the model would have depicted a much faster spread of farming settlements, Pinhasi's team contends.

In contrast, other researchers remain convinced that agriculture expanded primarily by the spread of cultivation techniques and year-round settlements among native Europeans (SN: 2/5/05, p. 88: Available to subscribers at http://www.sciencenews.org/articles/20050205/bob9.asp). The latest evidence for this perspective appeared in the Nov. 11 Science.

For that report, a team led by anthropologist Joachim Burger of Johannes Gutenberg University in Mainz, Germany, examined mitochondrial DNA, which is passed to offspring only from the mother. The researchers isolated this type of DNA from the bones of 24 adults who died in central European farming villages about 7,500 years ago. One-quarter of these individuals displayed a mitochondrial-DNA pattern that rarely occurs in modern Europeans. That pattern would be more common today if that early population had made a substantial genetic contribution to today's Europeans, the researchers contend.

If early farmers who moved into Europe didn't reproduce in large numbers, then native groups must have picked up the slack, Burger and his coworkers conclude.

Other DNA studies, including previous analyses of Y chromosomes in European men today, suggest that early Middle Eastern farmers had a substantial genetic impact in Europe, Pinhasi notes.

These conflicting DNA data may reflect intermarriage of immigrant farmer males with females native to Europe, suggests anthropologist Alex Bentley of the University of Durham in England.

Although he is sympathetic to the wave-of-advance model, archaeologist Peter Bogucki of Princeton University suspects that further research will show "a much more complicated combination of very rapid [agricultural] advances with long standstills."

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