BIZKAIA, SPAIN—Researchers from the University of the Basque Country have developed a new method for determining if individual flint flakes were produced by right- or left-handed knappers. “We focus on the butt of the flake which is where part of the percussion platform has been preserved. The fractures that appear on the platform are oriented according to the direction of the impact made on it by the percussor. Once the direction of the impact is known, it is possible, with a high degree of reliability, to determine whether it was produced by the left hand or the right hand,” Eder Dominguez-Ballesteros said in a press release. Studying the origins and development of laterality, or the preference for one side of the body over another, helps scientists to understand the evolution of the organization of the human brain. Earlier methods of determining laterality required the study of more than one flake for comparison. For more, go to "Neanderthal Tool Time."