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Science news that’s good for breaking habits, bad for generosity

A roundup of the good, the bad and the just plain interesting from the week's science headlines

Good news

Starting your day on autopilot might feel mindless, but a new MIT study shows the small part of the brain that controls planning plays a part in switching habits on and off. The findings jibe with previous studies that old habits are never truly broken, but replaced with different ones and scientists hope their research could lead to new methods of treating people with obsessive-compulsive disorder. In the study, a team of researchers used rewards to train rats turn left at a crossroads in a maze, according to an article published online Monday in the Proceedings of the National Academy of Sciences. The path became habitual. Even when the rewards were taken away, or mixed with a nauseant, the rats continued to take the same course, the scientists said in a press release. Then, scientists used optogenetics – light directed at cells to inhibit their function – to switch off a part of the brain called the infralimbic cortex for several seconds, just before the rats had to choose which way to turn. The rats broke their old habit and developed a new one, turning right instead. After repeating the optogenetics procedure however, the rats resumed their old habit, turning left in the maze. – Aleysha Haniff

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Bad news

Think your kid is great at sharing her toys? Maybe it's only when you're watching. New research published online in the journal PLOS ONE evaluated the "prosocial" behaviour of five-year-olds, testing their generosity. The children were given either one or four stickers, depending on the trial, then given the option to distribute another one or four stickers to another child. Children were more generous when they could see the person receiving the stickers and when the stickers were shared in a transparent container (so the other person could see exactly what they were getting). Those results were consistent, regardless of the number of stickers the first child received. In the article, the Yale researchers suggest that children, just like adults, are strategic with their generosity. – Aleysha Haniff

Just news

In the first inventory of minerals on another planet, NASA's Mars rover Curiosity found soil that bears a striking resemblance to weathered, volcanic sand in Hawaii, scientists said on Tuesday. The rover uses an X-ray imager to reveal the atomic structures of crystals in the Martian soil, the first time the technology, known as X-ray diffraction, has been used to analyze soil beyond Earth. Curiosity found the Martian sand grains have crystals similar to basaltic soils found in volcanic regions on Earth. Scientists plan to use the information about Mars's minerals to figure out if the planet most like Earth in the solar system could have supported and preserved microbial life. – Reuters

An international team of scientists have decoded the DNA of more than 1,000 people, building the largest compilation of human genetic variations to date. The initiative, called the 1,000 Genomes Project, hopes to create a resource to help determine genetic factors for disease. In the first phase, 1,092 people from 14 populations worldwide had their genomes analyzed and cataloged. Researchers from the Baylor College of Medicine Human Genome Sequencing Center say the project currently lists up to 98 per cent of sequences of rare gene variants in at least 1 per cent of the population, among other differences. Scientists think these rare variants are key to understanding how genetics play a part in diseases such as cancer and diabetes, they said. The report was published online Wednesday in Nature. – Aleysha Haniff

A prehistoric town unearthed in eastern Bulgaria is the oldest urban settlement found to date in Europe, a Bulgarian archaeologist said Thursday. Vasil Nikolov, a professor from Bulgaria's National Institute of Archaeology, said the stone walls excavated by his team near the town of Provadia are estimated to date between 4,700 and 4,200 B.C. He said the walls, which are three metres high and two metres thick, are believed to be the earliest and most massive fortifications from Europe's prehistory. "We started excavation work in 2005, but only after this archaeological season did we gathered enough evidence to back up this claim," Mr. Nikolov said. The team has so far unearthed remains of a settlement of two-story houses with a diameter of about 100 metres encircled by a fortified wall. The houses, as well as the copper needles and pottery found in graves at the site, suggest a community of wealthy people whose likely work was the once-lucrative production of salt. – The Associated Press

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