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This is Scientific American’s 60-Second Science. I’m Karen Hopkin. This will just take a minute.
When it comes to handedness, righties rule. And according to a new study, they have for a long time, because even half a million years ago, nine out of 10 European humans favored their right hands. The finding appears in the journal Laterality.
Scientists have long wondered where our handedness comes from. All other tool-using primates1 show no distinct hand preference when it comes to holding the stick or stone.
But have humans always been so heavily right-handed? Some scientists had previously2 detected a right-hand bias3 when they looked at the flaking4 patterns on ancient stone tools.
In this study, researchers turned to the teeth for answers. They analyzed5 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 asymmetrical6 marks showed that 93 percent of the individuals sampled tended to stuff things in their mouths from the right-hand side.
Handedness reflects our brain’s bilateral7 organization, which goes hand-in-hand with our proficiency8 with language. So our hand preference, and our penchant9 for speech, may extend deep into our evolutionary10 past.
Thanks for the minute. For Scientific American’s 60-Second Science, I’m Karen Hopkin.
1 primates | |
primate的复数 | |
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2 previously | |
adv.以前,先前(地) | |
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3 bias | |
n.偏见,偏心,偏袒;vt.使有偏见 | |
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4 flaking | |
刨成片,压成片; 盘网 | |
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5 analyzed | |
v.分析( analyze的过去式和过去分词 );分解;解释;对…进行心理分析 | |
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6 asymmetrical | |
adj.不均匀的,不对称的 | |
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7 bilateral | |
adj.双方的,两边的,两侧的 | |
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8 proficiency | |
n.精通,熟练,精练 | |
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9 penchant | |
n.爱好,嗜好;(强烈的)倾向 | |
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10 evolutionary | |
adj.进化的;演化的,演变的;[生]进化论的 | |
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