Our brains respond to our shadows as if they were another part of the body, according to a scientific study.
When we see something about to come into contact with the edge of our shadow, brain activity suggests it is as if they are about to touch us instead.
Scientists tested volunteers' reaction speeds and accuracy while distracting them with flashing lights.
They found that similar errors happened when lights flashed either next to a hand's shadow or the hand itself.
The brain develops an internal "map" which helps it define exactly where the body is - which helps it navigate around the world outside.
The results, by researchers at Royal Holloway College in London, suggest that the body's shadow may form part of that map.
The tests used shadows cast onto a white table in front of a seated volunteer.
The subject was asked to distinguish between touches on the thumb and forefinger of the hand, and the number of errors - and the overall reaction time - were recorded.
When flashing lights placed near the hand are activated, the number of errors rises and reaction time slows as the brain is forced to deal with the distraction.
However, when the flashes happened not alongside the hand itself, but instead alongside the shadow outline of the hand, the effect was exactly the same, suggesting the brain was equally distracted.
Flashes in the same place but without the shadow, or even flashes next to a disguised hand shadow forming a different shape all failed to produce this effect.
Professor Umberto Castiello, from Royal Holloway College, who led the research, said: "Our shadows help us reach out for objects. The brain was also capable of distinguishing between shadows cast by its body and those cast by other people."
(Agencies)
一项科学研究表明，大脑对影子作出的反应就像影子是身体的一部分一样。
当我们看到有东西将要接触到我们影子的边缘时，大脑的反应就像有东西要碰到我们的身体一样。
科学家们测试了志愿者们被闪光灯分散注意力时的反应速度和准确程度。
他们发现当灯光在手的影子旁边或手边闪烁时，志愿者们会犯相同的错误。
大脑中会显示出一张内在的“地图”，它帮助大脑确定身体的具体位置——帮助大脑在外部世界对身体导航。
伦敦皇家哈洛威学院的研究者们得出的结论指出身体的影子可能是大脑中“内在”地图的一部分。
试验中，坐着的志愿者将影子投影在身体前方的一张白色桌子上。
测试者被要求区分是大拇指还是食指被触摸，错误的次数以及整个反应的时间被记录下来。
当放在手边的闪光灯开始工作时，大脑不得不应付闪光灯造成的注意力分散，因此错误的次数增加，反应的时间缩短。
然而，当闪光灯的闪烁并不是发生在手边，而是在手的影子旁边时，效果却完全一样，这就意味着以上两种情况下大脑注意力分散程度是一样的。
如果闪光灯的闪烁发生在同样的地方，但不在影子旁，或者是在一个不同形状的伪装的手的影子旁边时，都不会有这样的效果。
主持此次研究的是伦敦皇家哈洛威学院的翁贝托·卡斯蒂耶洛教授，他说：“影子帮助我们伸手触摸物体。大脑还能够辨别自己身体的影子和别人的影子。”
(中国日报网站译)
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