The News Minute | August 16, 2014 | 12.06 pm ISTHumans have existed for 1.5 lakh years but why did technological advance happen suddenly at around 50,000 years ago?Archaeological evidence shows that certain tools and technology date to around 50,000 years ago, such as bone and antler tools, heat-treated and flaked flint, projectile weapons, grindstones, fishing and birding equipment, and a knowledge of fire, according to researchers quoted in an article published by Futurity.com.The article quotes researchers from Duke University, who argue that community living did influence human evolution. The article says: “A comparison of more than 1,400 ancient and modern skulls suggests human society advanced after people started being nicer to each other. And researchers say that change in behavior was likely due to a dip in testosterone.”Research on some animals revealed similar findings. The appearances of Siberian foxes changed after less aggressive foxes were bred selectively for generations. Their appearances took on a more juvenile appearance. Researchers at Duke University who compared the skulls of modern humans that were 80,000 years old with skulls that were between 10,000 and 38,000 years old, showed that reduction in testosterone was linked to a reduction in brow ridge and a shortening of the upper face. â€œIf prehistoric people began living closer together and passing down new technologies, they’d have to be tolerant of each other,” says Robert Cieri, who is currently with the University of Utah.