Experienced educator, writer, and counselor Robert Fettgather Ph.D. teaches general psychology and developmental psychology at Mission College in Santa Clara, California, where he serves as associate faculty. Robert Fettgather holds a BA in psychology from San Jose State University as well as Masters and Doctoral degrees.
What does an egg yolk have to do with it? Read on!
Sensation is the process by which sensory organs in the eyes, ears, nose, mouth, skin, and other tissues receive and detect stimuli. When sensory information is detected by a sensory receptor, then sensation has occurred. Perception focuses on the organization and interpretation of these stimuli within the human brain. These two work closely together to allow us to experience the world as coherent and meaningful. Of course, an Escher print (and other optical illusions) is one example of visual stimuli that challenges our ability to form a coherent perception.
Cloud gazing invites our own projections. A first glance, at a cloud embodies a sensation associated with your sense of vision-a cloud is just a cloud! But after gazing for awhile your brain may organize what you see into a perception of a face or the silhouette of a dog.
What is the relationship of sensation to perception? Think of it this way- sensation is input about the physical world obtained by our sensory receptors, and integrates with perception, the process by which the brain selects, organizes, and interprets these sensations.
Let’s consider another example. Have you ever noticed how the “hum” of a computer or an appliance might be bothersome at first- and then you don’t notice the sound at all? A sensation becomes a tuned out perception. That phenomenon is referred to as habituation.
In addition to cultural and individual differences, perceptions can be influenced by perceptual sets or expectancies. 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. In one well known experiment, subjects read the words FOLK CROAK SOAK. Then were asked, "what do you call the white of an egg?" That expectation tricked the subject into a wrong answer, yolk!
