Speed of the Human Eye on Moving Objects

The human eye takes approximately 1/25th of a second to process an incoming image. A human can perceive 25 different images per second or perceive the same object 25 times in a second. Unfortunately, the brain cannot process information that fast. Instead, what the brain appears to do, according to McGill University researchers, is store information from images and add to them. Once it has an image of, for example, a bird in flight, it simply adds new information to that image in what is called a beta effect.

Function

• The human eye takes in an image, like a snapshot. At this point it is only light. The retina senses the image and changes the light signals to electrical ones before passing the information to the brain. Nerves carry the signal from the retina to the brain which decodes the information, and using memory decodes the information to identify the image.

Film and TV

• A film or a television show is made up of still images. The human eye and brain perceive movement because the frames are moving past at a rate that makes the black space negligible. Film moves at about 24 frames per second (fps), while high definition video can be shot at up to 60 fps. Old films, such as those from the 1920s and 1930s appear jerky and everyone appears to be moving quickly because many of them were shot at 16 fps.

Dark and Light

• There is reason to believe that optimum perception is slowed when lights fade. According to the American Optometric Association, when lights dim, "Visual acuity may be reduced to 20/200 or less." The association also notes that some color vision is lost in darkened situations. Although information on the specific subject is not widely available, this likely means a slow down in the eyes and brains ability to process visual information.