左撇子更容易成爲天才，慣用左手是好事

The belief that there is a link between talent and left-handedness has a long history. Leonardo da Vinci was left-handed. So were Mark Twain, Mozart, Marie Curie, Nicola Tesla and Aristotle. It’s no different today – business leader Bill Gates is a left-hander, as is footballer Lionel Messi.
天才和左撇子之間自古以來就有着某種聯繫。達芬奇、馬克•圖文、莫扎特、居里夫人、尼古拉•特拉斯、亞里士多德都是左撇子。直到現在這種聯繫依然屢見不鮮，商界領袖比爾•蓋茨、足球運動員梅西都是左撇子。

But is it really true that left-handers are more likely to be geniuses? Let’s take a look at the latest evidence – including our new study on handedness and mathematical ability.
但是左撇子真的更容易成爲天才嗎？不妨來看看最新的調查：左右手偏向性實驗與數學能力的關係。

Unsurprisingly, the role played by handedness in mathematics has long been a matter of interest. More than 30 years ago, a seminal study claimed left-handedness to be a predictor of mathematical precociousness. The study found that the rate of left-handedness among students talented in mathematics was much greater than among the general population.
長期以來，左右手偏向性在數學中的作用備受矚目。30多年前，一項重要實驗表明，左手偏向性預示着數學能力提前發育。該試驗發現，在擅長數學的學生中，使用左手的人數比例遠大於不擅長數學的學生中使用左手的人數比例。

However, the idea that left-handedness is a predictor of superior intellectual ability has been challenged recently. Several scholars have claimed that left-handedness is not related to any advantage in cognitive skills, and may even exert detrimental effects on general cognitive function and, hence, academic achievement.
但是日前，左撇子的智力發育更好這一說法面臨挑戰。一些學者認爲，左手偏向性和認知技巧優勢沒有任何聯繫，左手偏向性甚至可能有損一般的認知能力，並因此妨礙獲得學術成就。

For example, one study discovered that left-handed children slightly under-performed in a series of developmental measures. Also, a recent review reported that left-handers appear to be slightly over-represented among people with intellectual disabilities. Another large study found that left-handers performed more poorly in mathematical ability in a sample of children aged five to 14.
比如有項實驗發現慣用左手的兒童在種種發展性測試中表現欠佳。最近也有報告表示左撇子相較其他人更多地表現出了智力障礙。更有大型試驗稱，通過對5到14歲的兒童進行數學能力測試，發現其中慣用左手的孩子表現更加不如人意。

Left-handers seem to have, on average, an edge when solving demanding mathematical tasks – at least during primary school and high school. Also, being strongly right-handed may represent a disadvantage for mathematics. Taken together, these findings show that handedness, as an indicator of connectivity between brain hemispheres, does influence cognition to some extent.
一般來說，左撇子可能在解決複雜數學問題上有些優勢——至少在小學和中學是這樣。凡事都只使用右手可能不利於數學能力的發展。綜合來看，左右手偏向性不但表明左右大腦半球互有連結，還在某種程度上影響着認知能力。

That said, handedness is just an indirect expression of brain function. For example, only a third of the people with a more developed right hemisphere are left-handed. So plenty of right-handed people will have a similar brain structure as left-handers. Consequently, we need to be cautious in interpreting people’s hand preference – whether we see it as a sign of genius or a marker for cognitive impairment.
這就說明左右手偏向性間接代表着大腦功能。比如只有三分之一的左撇子右腦發育更完全。所以很多右撇子和左撇子的大腦發育程度完全相同。這樣一來，在定義不同的左右手偏向性是天才的象徵還是認知障礙的外在表現時，我們就要謹慎一些。