These Faces Are The Same Color!

Akiyoshi Kok's newest illusion is blowing my mind. You've got a white face and a black face. Psych! They are both the exact same gray. The face on top appears to be illuminated by a dimmer light source than the one below.

So before putting anything into conscious awareness, the brain figures, "Well, if this face is sending the eye such a light gray under such dim light, it must be an efficient reflector of light. It must be pretty intrinsically bright." So let's perceive it with more luminance, more lightness than it really has.

But this face produces the same gray sensation under what appears to be a comparatively brighter light source. So it must be an inefficient reflector of light. So we perceive it as darker than it really is.

Looks like the brain has taken two L's on this one, but that's a W. Because to survive, an organism doesn't need to know sensations. It's often better to figure out intrinsic properties—the things about stuff that stays the same regardless of the environment.

Now, that can lead to mistakes like in this illusion, but as I've said before, for a species to continue, it is better to be alive than right.