perceptual。
a） A motor set is a readiness to make a quick； prepared response
b） A mental set is a readiness to deal with a situation； such as a
problem…solving task or game； in a way determined by learned
rules； instructions； expectations； or habitual tendencies。
Mental sets can actually prevent problem…solving when old
rules do not fit new situations。
c） A perceptual set is a readiness to detect a particular stimulus
in a given context
D。 Creatively Playful Perception
1。 Perceptual creativity involves experiencing the world in ways that are
imaginative； personally enriching； and fun
E。 Final Lessons
1。 A perceptual experience in response to a stimulus event is determined
not only by the stimulus but also by the person experiencing it。 In
addition to sensation； final perception depends on past experience；
expectations； wants； goals； values； and imagination。
2。 A proper balance of top…down and bottom…up processing achieves the
basic goal of perception： to experience what is out there in a way that
maximally serves your needs as a biological and social being； moving
about and adapting to your physical and social environment。
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DISCUSSION QUESTIONS
1。 Why are there separate chapters on sensation and perception？ What are the differences
between the two？
2。 Which is more susceptible to cultural or contextual influence； sensation or perception？
Why？
3。 How are individuals able to tell when their perceptions have been influenced by cultural or
contextual factors？ Is there a way to eliminate these biases from perception？ These factors
probably always influence perception； but knowing that they do gives the perceiver
knowledge that may help minimize its negative impact。
4。 Are the differences in perception among humans likely to be larger or smaller than the
differences in perception among ants？ Assuming that human cultures are more diverse
than ant cultures； the differences in perception should be greater for humans。 Larger
cultural differences would produce larger variations in perception。
5。 You might ask students if they believe that advertisers put hidden messages in their
advertisements。 Follow up by asking if they believe those messages work。 You can use this
to lead into a discussion of subliminal perception and its supposed effects。 Stories of
subliminal visual messages go back to claims of their inclusion in movies in the 1950s。
Subliminal verbal messages have been discussed at least since the controversy about the
Beatles supposedly putting hidden messages in their albums in the late 1960s。 However；
the evidence that these messages have any real effect on behavior is currently lacking。
Stories about subliminal messages continue to regularly appear in the media； and it is
surprising how many people believe that the messages work。
6。 As an example of motion parallax； you might ask students if they have ever traveled with
young children on a clear night with the moon near the horizon to one side of the road on
which you are traveling。 Whereas the trees； houses； and hills seem to move steadily by； the
moon appears to be traveling along with you。 Many times young children will exclaim that
the “moon is following us。” There have even been UFO reports generated by this
phenomenon on cloudy nights when adults have mistaken the moonlight for a flying object
darting in and out of the clouds and following them along the horizon。
7。 To illustrate the fact that the brain interprets messages from the skin’s hot and cold
receptors relative to previous and surrounding stimuli； set up three small basins in the
front of the class。 Fill one with hot water （but not so hot that it will burn someone’s skin）；
one with cold water； and one with luke…warm water。 Have students put one hand in the
basin of hot water and the other hand in the basin of cold water。 Then have them place
both hands in the basin of warm water。 They should notice that in the warm water； one
hand （the one that was in the cold water） will sense it as being hot； while the other hand
（the one that was in the hot water） will sense it as being cold。
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PSYCHOLOGY AND LIFE
SUPPLEMENTAL LECTURE MATERIAL
Eyes and Camera Lens
For many years； it was believed that the eye worked like a camera； and there are some similarities。
For instance； both the pupil of the eye and the aperture of a camera contract and expand in
response to a respective increase or decrease in the amount of light entering the apparatus。
Nevertheless； in paring the human eye to a camera； some of the differences between these two
are striking。
Perhaps the strangest difference between the human eye and a camera lens is the position of the
retina and the analogous film。 For a camera to be like the human eye； we would have to load our
film into the camera backward。 That is； the photoreceptors actually pick the light up off the back of
the surface of the eyeball。 A camera must be held relatively still to capture a clear image； but when
the eyeball is held still； the picture disappears。 Both the camera and the eye have a lens that focuses
an image on a surface； but the two have different methods of focusing。 The lens in a camera moves
closer to or farther from the film in order to focus the image on the film； the lens in the eye changes
shape to focus the image on the retina。 This process is called acmodation。
An upside…down mirror image is focused on both the film and the retina； however； the film and the
retina differ in that the film records the image exactly as it is projected。 The photoreceptors in the
retina receive information from visual stimuli； those stimuli are analyzed and reconstructed as they
move through the visual system from the retina to the cortex。 What we perceive is a picture that is
not identical to the item we are looking at。 Photographs in which people have their feet extended
closer to the camera in front of them are ical because we take relative distances into account and
perceive the feet as being a constant size。
Everyday Examples of Gestalt Principles
Bring in everyday examples of the Gestalt principles of perception from magazines or artworks。
Transparencies of the examples can be made on a copy machine； and then used on overhead
projectors。 For example； in Escher’s Mosaic II； one sees a group of black creatures on either a white
background or a group of white creatures on a black background。 H。 A。 Broos explains how
Escher’s prints have been used in geology； chemistry； and psychology in The World of M。 C。 Escher。
This book also contains a chronological survey of Escher’s work and includes a number of useful
examples； such as illustrations of figure and ground in the woodcuts “Sky and Water I” and “Sky
and Water II。”
A Brief History of Gestalt Psychology
The Gestalt movement in psychology was established in Germany in the early 1900s； and was
based on the Gestaltist’s opposition to the structuralist movement。 In essence； the structuralist
movement proposed that all phenomena could be broken down into their most primitive perceptual
elements。 The Gestaltists took exception to that philosophy； arguing that psychological phenomena
could be understood only if they were studied as organized； structured “wholes；” thus maintaining
the “unitary essence” of the phenomena。
The Gestaltists extended this philosophy to learning； in viewing it as a restructuring or
reorganization of an entire situation； and a process that often included insight as a critical aspect of
that process。 Brain physiology was perceived in the same context； in that Gestaltists saw the brain
as isomorphic； as having a relationship between the excitatory fields in the cortex and the
conscious experience of the individual。
Gestalt psychology； as a distinct discipline； is rarely found today； although many of the insights it
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fostered and discoveries have been incorporated into contemporary psychology。
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PSYCHOLOGY AND LIFE
BIOGRAPHICAL PROFILES
Eleanor Gibson （b。 1910）
Eleanor Gibson graduated from Smith College in 1931 and obtained her Ph。D。 at Yale in 1938。
Gibson was instrumental in studying perceptual development in children； inventing the visual cliff
as a means of studying depth perception。 Her interests in experimental psychology were influenced
by her husband； J。 J。 Gibson； whose research and theory on perception have challenged the more
popular Gestalt and information…processing accounts that hold that a stimulus undergoes
considerable interpretation via cognitive processes。 Gibson received the American Psychological
Association Distinguished Scientific Contribution Award for her research on depth perception。
William Rutherford （1839–1899）
William Rutherford was born in Ancrum； Scotland； and received his M。D。 at the University of
Edinburgh。 His first academic appointment was at King’s College； London； but he eventually
returned to Edinburgh as a professor of physiology in 1878。 He is well known for his research on
the influence of the vagus nerve on circulation and on drug effects on the secretion of bile； as well as
for his physiological textbook published in 1880。 He is best known in psychology for his
“Telephone Theory” of pitch perception； which argues that the Organ of Corti vibrates in a manner
that duplicates the frequency of vibrations of the tympanic membrane and ossicles。 This frequency
theory of pitch perception； a major petitor to Helmholtz’s place theory； seems to account well
for our perception of low… and middle…frequency sounds。
Max Wertheimer （1880–1943）
Wertheimer was born in Prague； Austria…Hungary。 His father directed a private business college
and his mother was an acplished amateur violinist。 Wertheimer studied law； philosophy； and
psychology at Charles University in Prague。 He later studied philosophy and psychology at the
University of Berlin under Carl Stumpf； then moved to the University of Surzburg in 1904； obtaining
his Ph。D。 under Oswald Kulpe。 Wertheimer first discovered the phenomenon of apparent motion