Optical IllusionsRusk• Psychology

Perception

Size constancy: ability to remember the size of an object no matter where it is located

Color constancy: ability to perceive an object as the same color regardless of the environment

Shape constancy: ability to perceive an object as having the same shape regardless of the angle

Space constancy: ability to judge distance by perceiving either self or object movement

Perceptual constancies use memory to maintain order in the world.

Perceptual Organization

Gestalt: making incomplete organization whole (they way something should be rather than how it actually is)

Similarity: grouping like things together

Proximity: grouping things together that are near each other

Closure: filling in the missing details

Principles of Organization

Closure Proximity

Similarity

Perceptual Organization

Perceptual Illusions

Franz Müller-Lyer designed this illusion in 1889.

Illusions are misperceptions. They illustrate how we organize objects into meaningful perceptions .

Which line is longer?

Muller-Lyer Illusion at Work

The Vertical-Horizontal Illusion

Are the two lines the same length?

In the figure-ground illusion, the figure is in the front while the ground is in the back. Do you see the faces facing one another or do you see the vase?

Figure-Ground Illusion

Click the forward arrow to move the cylinder on the right forward to the middle cylinder.

Which cylinder is largest?

Which cylinder is largest?

Which cylinder is largest?

For the next Illusion, pair up and have one partner write down the words as the other partner says them.

This picture is ambiguous in three ways:

• As a small cube in front of a larger cube; • As a large cube with a corner cubelet cut

out; • As a small cube inside three

perpendicular adjoining planes.

Stare at the central dot, and move your head forwards and backwards.