Discovered: the most depressing day of the year; the problem with dieting after age 75; the truth about chimps; the dingo might not even be Australian.
Today could be the year's most depressing Monday. Did your case of the Mondays get you especially down today? Science might have the answer to why. According to a mathematical formula created by UK psychologist Cliff Arnall in 2005, the bluest of 2013's Blue Mondays lands either today, January 14th, or next week, on the 21st. Variables accounting for the extra-upsetting mood today include winter weather, bank accounts drained by holiday spending, seasonal overeating, and unfulfilled New Year's resolutions. [New York Daily News]
Dieting late in life isn't very effective. Once you reach the age of 75, reward yourself by eating whatever you want. At least that's one of the takeaways from new research by Penn State nutritionist Gordon Jensen. Diets high in sugar and fat didn't effect health outcomes for people in this age group, Jensen and his colleagues found after studying 449 septuagenarians for five years. Jensen says, "The results suggest that if you live to be this old, then there may be little to support the use of overly restrictive dietary prescriptions, especially where food intake may already be inadequate. However, people who live on prudent diets all their lives are likely to have better health outcomes." [Penn State]
Do chimps know how to play fair? Chimpanzees apparently aren't entirely selfish—researchers have observed them sharing goods evenly amongst themselves in certain scenarios. "Humans and chimpanzees show similar preferences in dividing rewards, suggesting a long evolutionary history to the human sense of fairness," says psychologist Darby Proctor of the Yerkes National Primate Research Center. But some researchers criticize findings that suggest chimps understand fairness. "If anything, Proctor’s study suggests that there is no fairness sensitivity in chimpanzees," says Keith Jensen of the University of Manchester. The findings at issue here have to do with the "ultimatum game." In this situation, "giver" subjects have to split a good with a "receiver." If the receiver accepts the offering made by the giver, both get to keep their shares. If the receiver rejects it because it's perceived as unfair, neither one gets to keep anything. Proctor found that chimps and preschool children performed quite similarly in this experiment. She thinks this is a sign that chimps understand the concept of fairness in much the same way that humans do—but looking at the same data, Jensen says receiver chimps' actions "suggest that they were not sensitive to unfairness but were motivated only by getting rewards." Watch a video about the experiment below and decide for yourself whether chimps know how to play fair or not. [ScienceNews]
Genetics reveal mass Indian migration. By studying DNA from Aboriginal Australians, geneticists have found that a mass wave of immigration occured from India to Australia more than 4,000 years ago. The findings challenge the idea that Australia was for the most part isolated before Europeans stepped in during the 19th century. "We have a pretty clear signal from looking at a large number of genetic markers from all across the genome that there was contact between India and Australia somewhere around 4,000 to 5,000 years ago," says Max Planck Institute for Evolutionary Anthropology professor Mark Stoneking. "Our results show that there were indeed people that made a genetic contribution to Australians from India." Humans weren't alone coming to Australia, the scientists theorize, but they may have also brought the dingo with them, meaning one of Australia's most iconic animals might not even be Australian. [BBC News]