The Influence of Perceptual Sets

An associate faculty at Mission College in Santa Clara, California, Robert Fettgather Ph.D. teaches general psychology, abnormal psychology, developmental psychology, and psychiatric interviewing. Dr. Robert Fettgather has co-authored several papers on social issues. He is interested in research on sensation and perception.

Perception considers the interpretation of sensation and seems to follow some basic guiding principles. It should be noted that individual and cultural differences in perception have been reported. It is process by which people take all the sensations they experience at any given moment and interpret them in some meaningful fashion.

The principle of figure-ground relationships can be illustrated by looking at reversible figures, which are visual illusions in which the figure and ground seem to switch back and forth. Closure refers to the brain's tendency to complete figures that are incomplete.

Visual perception of depth, referred to as depth perception, seems to be present in childhood at a very early age. Visual cues for depth that necessitate the use of just one eye are called monocular cues. Visual cues that use both eyes are referred to as binocular cues and include both convergence as well as binocular disparity.

In addition to cultural and individual differences, perceptions can be influenced by perceptual sets or expectancies as noted in the introduction. One example of perceptual expectancy is top-down processing. This happens  when an individual utilizes pre-existing knowledge to place certain features into an organized whole. If there is no expectancy to help organize information, a person might use bottom-up processing to build a complete perception by making sense of the smaller features piece by piece. With a friend, try this experiment from Martin Bolt: print on a piece of paper the words below. Then read aloud these three words as your friend looks at the words and reads along with you:

FOLK CROAK SOAK

Next, immediately ask, what do you call the white of an egg? That expectation tricks the friend into a wrong answer, yolk!