Module 16

What do we mean when we say that, in perception, "the whole is greater than the sum of its parts"?

Gestalt psychologists used this saying to describe our perceptual tendency to organize clusters of sensations into meaningful forms or coherent groups.

What is the rapid sequence of events that occurs when you see and recognize a friend?

Light waves reflect off the person and travel into your eye, where the receptor cells in your retina convert the light waves' energy into neural impulses sent to your brain. Your brain processes the sub dimensions of this visual input-including color, depth, movement, and form-separately but simultaneously. It interprets this information based on previously stored information and your expectations into a conscious perception of your friend.

What are two key theories of color vision? Are they contradictory or complementary? Explain.

The Young-Helmholtz trichromatic theory shows that the retina contains color receptors for red, green, and blue. The opponent-process theory shows that we have opponent-process cells in the retina and thalamus for red-green, yellow-blue, and white-black. These theories are complementary and outline the two stags of colors vision: (1) The retina's receptors for red, green, and blue respond to different color stimuli. (2) The receptors' signals are then processed by the opponent-process cells on their way to the visual cortex in the brain.

These creatures probably have very poor (color/black-and-white vision)

color

In terms of perception, a band's lead singer would be considered (figure/ground), and the other musicians would be considered (figure/ground).

figure, ground

Cats are also able to open their ____ much wider than we can, which allows more light into their so eyes so they can see better at night

pupils

Some nocturnal animals, such as toads, mice, rats, and bats, have impressive night vision thanks to having many more ___ than ____ in their retinas

rods, cones

How do we normally perceive depth?

We are normally able to perceive depth thanks to the binocular cues that are based on our retinal disparity, and monocular cues including relative height, relative size, interposition, linear perspective, light and shadow, and relative motion.

There are no receptor cells where the optic nerve leaves the eye. This creates a blind spot in your vision. Can you explain why?

Your blind spot is on the nose side of each retina, which means that objects to your right may fall onto the right eye's blind spot. Objects to your left may fall on the left eye's blind spot. The blind spot does not normally impair your vision, because your eyes are moving and because one eye catches what the other misses.