心理学与生活-第28章
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G。 Binocular and Motion Cues
1。 Binocular disparity is the displacement between the horizontal
positions of corresponding images in the two eyes
2。 Convergence is the turning in of the eyes when they fixate on a single
object。 The eyes must converge more for objects that are near than for
objects that are distant。
3。 Relative motion parallax provides information about depth as an
individual moves because objects that are close appear to move more
than objects that are farther away
H。 Perceptual Constancies
1。 Perceptual constancy refers to the tendency to see the world as invariant;
constant; and stable; despite changes in the stimulation of sensory
receptors
2。 Size and shape constancy
a) Size constancy refers to the ability to perceive the true size of an
object despite variations in the size of its retinal image
b) Shape constancy refers to the ability to perceive correctly an
object’s actual shape; even when the object is slanted away
from the viewer; making the shape of the retinal image
substantially different from that of the object itself
c) Orientation constancy refers to the ability to recognize the true
orientation of the figure in the real world; even though its
orientation in the retinal image is changed
d) Lightness constancy is your tendency to perceive the whiteness;
grayness; or blackness of objects as constant across changing
levels of illumination
IV。 Identification and Recognition Processes
A。 Bottom…Up and Top…Down Processes
1。 Bottom…up processing is taking sensory data into the system and
sending it upward for extraction and analysis of relevant information。
It is anchored in empirical reality and deals with bits of information
and the transformation of concrete; physical features of stimuli into
abstract representations。 Also called data…driven processing。
2。 Top…down processing is when past experiences; knowledge;
motivations; cultural background; and expectations affect perception;
as higher mental functioning influences how objects and events are
understood。 Also called hypothesis…driven processing。
3。 Phonemic restoration occurs when there are gaps in physical signals
and perception replaces part of a word that was obscured by noise in
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a very loud environment
B。 Object Recognition
1。 Irving Biederman has proposed that all objects can be assembled from
a set of geometrical ions; or geons。 From a set of 36 geons; Biederman
believes that perception can make a strong guess at the nature of an
object。
C。 The Influence of Contexts and Expectations
1。 Expectations can influence hypotheses about what is out there in the
world and can influence what is actually perceived
2。 It takes longer to recognize an object when it is seen in the wrong
context; not in a familiar place
3。 Object identification is a constructive; interpretive process
4。 Set is a temporary readiness to perceive or react to a stimulus in a
particular way。 There are three types of sets: motor; mental; and
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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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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BIOGRAPHICAL PROFILES
Eleanor Gibson (b。 191