这些草莓不是红色的，为什么你的大脑会认定它们就是？

这些草莓不是红色的，为什么你的大脑会认定它们就是?

These strawberries look red ­(almost), like fresh fruit should. But this tasty image doesn’t have any rosy hues in it at all. Zoom way in, and you’ll find that the pixels that make up this snack are actually shades of blue and green.

这些草莓看起来(几乎)是红色的，就像新鲜水果一样。但这张美味的照片一点也没有玫瑰色。放大一点，你会发现构成这种零食的像素实际上是蓝色和绿色的阴影。

You’re seeing scarlet because of a visual phenomenon called color constancy. We perceive color based on the wavelength of light an object reflects. But those wavelengths are always in flux. Color constancy helps us adjust to those changes, keeping an item’s tone the same even if its surroundings change dramatically. For example, if a sunset floods the light outside with a deep yellow, blue beach chairs will still look blue.

你能看到鲜红色是因为一种叫做颜色恒常性的视觉现象。我们根据物体反射的光的波长来感知颜色。但是那些波长总是在不断变化。颜色恒常性有助于我们适应这些变化，即使周围环境发生巨大变化，也能保持物品的色调不变。例如，如果日落时外面的光线被深黄色的沙滩椅淹没，蓝色的沙滩椅看起来仍然是蓝色的。

Scientists once thought that color constancy was rooted solely in the brain, says David H. Foster, professor of vision systems at the University of Manchester in England. If the light shifted, altering the wavelengths reflecting off an object as a result, color receptors in the eye would adjust so the brain would see it in the same way regardless. But other experts argued that people used their experience to infer what a scene was supposed to look like—no photoreceptors involved.

英国曼彻斯特大学(University of Manchester)视觉系统教授福斯特(David H.Foster)说，科学家们曾经认为，颜色恒常性完全植根于大脑。如果光线移动，从而改变了反射到物体上的波长，那么眼睛中的颜色受体就会调整，这样不管波长怎样变化，大脑仍可以以同样的方式看到它。但其他专家认为，人们利用自己的经验推断出一个场景应该是什么样的，而不受波长影响。

The latest research suggests each mechanism plays a role. Neurons adjust to maintain consistency, but the memory of what a given object looks like is also essential. In the case of these berries, it’s the light source that turns a simple image into a full-blown illusion. Sensing the blue tint in the photo, our brains unconsciously but systematically subtract cyan from each gray pixel in order to restore the rose-colored berries we know we should see.

最新研究表明，每一种机制都起着作用。神经元会调整以保持一致性，但对给定物体的记忆也是必不可少的。在这些浆果的例子中，是光源将一个简单的图像变成了一个全面的幻觉。我们的大脑感应到照片中的蓝色，会无意识但有系统地从每个灰色像素中减去青色，以恢复我们知道应该看到的玫瑰色浆果。