科学60秒:古欧洲人都是“右撇子”
Scientists have long wondered where our handedness comes from.All other tool-using primates show no _____2_____ hand preference when it comes to holding the stick or stone.
But have humans always been so heavily _____3_____?Some scientists had previously detected a right-hand bias when they looked at the flaking patterns on ancient stone tools.
In this study, researchers turned to the teeth for answers.They analyzed the scratches accidentally left by stone tools on teeth from human fossils collected from a half-million-year-old site in northern Spain and later sites throughout Europe.These asymmetrical marks showed that 93 percent of the individuals sampled tended to _____4_____ in their mouths from the right-hand side.
Handedness reflects our brain’s bilateral organization, which goes hand-in-hand with our proficiency with language.So our hand preference, and our penchant for speech, may _____5_____ our evolutionary past.
【视听版科学小组荣誉出品】