Many people are able to perceive polarization of light. It may be seen as a yellowish horizontal bar or bow-tie shape (with “fuzzy” ends, hence the name “brush”) visible in the center of the visual field against the blue sky viewed while facing away from the sun, or on any bright background.

The name comes from a joke about a Texan who fires some shots at the side of a barn, then paints a target centered on the biggest cluster of hits and claims to be a sharpshooter

a part of the human visual system which might be specialized for facial recognition,

the experience of seeing meaningful patterns or connections in random or meaningless data.

a psychological phenomenon involving a vague and random stimulus (often an image or sound) being perceived as significant. Common examples include seeing images of animals or faces in clouds, the man in the moon or the Moon rabbit, and hearing hidden messages on records played in reverse.

In photography, acutance is the edge contrast of an image. Acutance is related to the amplitude of the derivative of brightness with respect to space. Due to the nature of the human visual system, an image with higher acutance appears sharper even though an increase in acutance does not increase real resolution.

Eigengrau (German: “intrinsic gray”), also called Eigenlicht (“intrinsic light”), dark light, or brain gray, is the color seen by the eye in perfect darkness. Even in the absence of light, some action potentials are still sent along the optic nerve, causing the sensation of a uniform dark gray color. Eigengrau is perceived as lighter than a black object in normal lighting conditions, because contrast is more important to the visual system than absolute brightness.

The Ganzfeld effect (from German for “complete field”) is a phenomenon of visual perception caused by staring at an undifferentiated and uniform field of color. The effect is described as the loss of vision as the brain cuts off the unchanging signal from the eyes. The result is “seeing black” - apparent blindness.

Zebra’s stripes aren’t to disguise it against the background foliage, etc. but to make it harder for a predator to distinguish and target individuals in the herd.