大凡人类，无论几个月大的婴儿，还是几十岁的成年人，都对蛇极端敏感。把花和蛇放在一起，人类总是先看到蛇。按照科学家的观点，蛇对人类构成威胁，人类为了生存而进化出了先对蛇有反应的视觉能力。那么，人类是怎么从小就能识别出蛇的呢？
科学家的最新研究发现，在识别蛇这一问题上，儿童与成年人可能还存在区别。对儿童来说，色觉可能发挥了相当重要的作用，蛇的鲜艳外表加快了儿童的反应速度。而对成年人来说，识别蛇主要靠辨别它的形状特征，颜色特征已不再重要。
位于日本爱知县犬山市的京都大学灵长类研究所的一个研究小组最近对111名4至6岁的儿童进行了实验。他们让这些孩子观看8张各种鲜花和1张蛇的照片，这9张照片在触摸屏上以纵横各3张的形式排列，照片分黑白和彩色两组，然后让儿童迅速寻找其中蛇的照片。
研究人员发现，儿童在彩色照片上花费的时间均比起黑白照片要快0.1到0.2秒。这与成年人有很大不同。此前多个研究表明，无论照片是彩色还是黑白，成年人所花的时间没有差别。
这项研究已发表在新一期英国学术刊物《科学报告》（Scientific Reports）上。正高信男指出，人类和类人猿等高级灵长类色觉非常发达，这帮助他们在幼儿时期就能迅速发现蛇，这并非偶然，而是为了保护自身而出现进化的结果，发达的色觉也成功地提高了人类祖先的生存能力。(生物谷 Bioon.com)
doi:10.1038/srep00080
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The influence of color on snake detection in visual search in human children
S. Hayakawa; N. Kawai; N. Masataka
It is well known that adult humans detect snakes as targets more quickly than flowers as the targets and that how rapidly they detect a snake picture does not differ whether the images are in color or gray-scale, whereas they find a flower picture more rapidly when the images are in color than when the images are gray-scale. In the present study, a total of 111 children were presented with 3-by-3 matrices of images of snakes and flowers in either color or gray-scale displays. Unlike the adults reported on previously, the present participants responded to the target faster when it was in color than when it was gray-scale, whether the target was a snake or a flower, regardless of their age. When detecting snakes, human children appear to selectively attend to their color, which would contribute to the detection being more rapidly at the expense of its precision.
