Introduction to Psychology

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Name Description Example Image

Interposition

When one object

overlaps another

object, we view it as

closer.

At right, because the

blue star covers the

pink bar, it is seen as

closer than the yellow

moon. (^)
Aerial
perspective
Objects that appear
hazy, or that are
covered with smog or
dust, appear farther
away.
The artist who
painted the picture on
the right used aerial
perspective to make
the clouds more hazy
and thus appear
farther away. (^)

Perceiving Motion

Many animals, including human beings, have very sophisticated perceptual skills that allow them
to coordinate their own motion with the motion of moving objects in order to create a collision
with that object. Bats and birds use this mechanism to catch up with prey, dogs use it to catch a
Frisbee, and humans use it to catch a moving football. The brain detects motion partly from the
changing size of an image on the retina (objects that look bigger are usually closer to us) and in
part from the relative brightness of objects.

We also experience motion when objects near each other change their appearance.
The beta effect refers to the perception of motion that occurs when different images are
presented next to each other in succession (see Note 4.43 "Beta Effect and Phi Phenomenon").
The visual cortex fills in the missing part of the motion and we see the object moving. The beta
effect is used in movies to create the experience of motion. A related effect is
thephi phenomenon, in which we perceive a sensation of motion caused by the appearance and