Cog Psych Ch3 Learning about the World Around Us
PG to pay Attention : 59-73; 84-95
- others pick out specific patterns of movement or fire when certain angles or notches in view.
-even neurons (in monkey's brain) fire only when monkey's hand in vew (whether fingers stretched out or
clenched in fist) or only when another monkey's face is view
- visual perception involves far more than simple detection of stimulus input's properties.
-one consideration,input's various attributes detected by separate brain systems,
-further step required to reunite various attributes so we recognize ex a squirrel that brown and moving and
leaves that are green
-large role the perceiver plays-not just as a detector of incoming information, but as active interpreter of
- receive information about world through various sensory modalities:
-no question, though that for humans vision is the dominant sense.
-reflected in how much brain area devoted to vision compared any of the other senses.
-reflected many aspects of our behavior.
-ex , if visual information conflicts w/ information received from other senses, usually place trust in
-basis for ventriloquism, which see dummy's mouth moving while sounds coming from
-Vision wins this contest, experience illusion voice coming from dummy
- how does vision operate?
-As you read page, can see individual letters printed letters you know and can identify.
-letters form words, you also can recognize; could say out loud requested know the meaning of words, so easily
-How is this possible? How do you manage to perceive then recognize, objects you see every day?
-problem, first, of form perception, process through manage to see what basic shape and size of object are.
-Next problem of object recognition, process you identify what the object is
Why Is Object Recognition Crucial?
-Virtually all knowledge and use of knowledge depend on form perception and
-think about a physician who might know how to treat measles, but doesn't knowtorecognize case of this
illness when encounters one.
-knowledge about treatment becomes useless, physician doesn't know when (or with which pattonts)
-. Without recognition, you cannot bring your knowledgtobear on the world.
-object recognition crucial for learning.
-virtually all learning, one must combine new information w/ information learned previously.
-to happen, one must categorize things properly.
-If integrate new knowledge with old, need to realize person before you today same person as one you
-Without proper categorization, no way to combine and integrate information.
-essential base for learning and memory. Beyond the Information Given
-Chapter 2, process of object recognition begins: detection of simple visual features.
-Early 20th century, group of psychologists called "Gestalt psychologists" noted our perception of visual world
organized ways that the stimulus input is not. 1
argued, the organization must be contributed by perceiver; why, they claimed, perceptual whole often different
from the sum of its parts.
-Jerome Bruner coined phrase"beyond the information given" to describe some of ways our perception of a
stimulus differs from (and goes beyond) the stimulus itself (Bruner, 1973).
- Necker cube.
-drawing called an "ambiguous figure" - more than one way to perceive it.
-can be perceived as cube viewed from above (similar to the cube marked "1\.' in the figure); alternatively cube
viewed from below (similar to the cube marked "B").
- Both perceptions fit perfectly well with information received by eyes, and so drawing itself fully compatible
w/ either of these perceptions
- lines on page are neutral with regard to the shape's configuration in depth; the lines on the
page dont specify which is "proper" interpretation.
- ones perception of cube, however, is not neutral.
-Instead, perceive cube as having one configuration or other-similar either Cube A or Cube
-perception, other words, goes beyond information given in drawing, by specifying an arrangement in depth.
- same point made for many other stimuli. Consider Figure 3.2
- it is neutral w/ regard to figure/ground organization, determination of what is the figure (depicted object,
displayed against a background) and what is ground.
-perception of figure, not neutral about this point.
Instead, your perception somehow specifies looking at vase not at profiles, or looking at profiles ,not at
-both examples, perception contains information-about how form arranged in depth, or which part of form is
figure and which is ground- not contained within stimulus itself.
this is information contributed by you, the perceiver.
Organization and "Features"
-One might suppose our perception of world proceeds in two broad steps.
(1) collect information about stimulus, so we know (for example) what corners or angle or curves contained in
(2) interpret information, presumably in this second step we "go beyond the information given"-deciding how
form is laid out in depth (as in Figure 3.1), deciding what is figure and what is ground (Figure 3.2), and so on.
- However, view is wrong.
-one concern, mentioned in Chapter 2 : do not just "pick up" information in the stimulus, the way a camera
might record light energies reaching it.
- evident, in the phenomenon of lateral inhibition, which visual system manages to emphasize some aspects of
input (the edges) , de-emphasize others (regions of uniform brightness) from very beginning.
- addition, number of observations suggest our interpretation, our organization of input, happens before we start cataloguing input's basic features,and not after, as secondary "interpretive" step.
-Figure 3.3. Initially, black shapes seem have no meaning, after moment, most people discover word "hidden" in
-people find way toreorganize figure so that familiar letters come into view.
-let's be clear about what this means.
-At start, form seems not to contain features needed to identify L, the I, and so on.
-Once form is reorganized, does contain these features and letters immediately recognized.
-Apparently, cataloguing of input's features depends on prior step which form organized by viewer:
- one organization, key features absent; another, plainly present.
-the features are as much" in the eye of the beholder" as in the figure itself.
- Figure 3.4, although, truth, most of features needed for recognition absent from figure.
- easily "provide" missing features, though, thanks to fact you interpret black marks in figure as shadows cast by
-Given interpretation and extrapolation it entails, no trouble, "fill in" missing features, read the word despite the
scanty information provided by stimulus.
- demonstrations create potential paradox.
- one side, perception of any form must start w/ stimulus , must be governed by what is in that stimulus.
-Figure 3.4 will not look to you like a photograph of Queen Elizabeth-
- basic features of the queen just not present.
-suggests : features must be in place before an interpretation is offered, features govern the interpretation.
- other side, Figures 3.3 and 3.4 suggest opposite also the case: features one finds in an input depend on how
figure is interpreted.
-Therefore, the interpretation, not features, must be first.
- solution straightforward hinges on fact the brain relies on parallel processing
- other words, brain areas analyzing pattern's basic features do their work same time as brain
areas analyzing pattern's large-scale configuration.
-two brain areas constantly interact, so perception achieved one makes sense at both the
large-scale and fine-grained levels.
The Logic of Perception
Overall, stimulus by itself does not tell you elements of input are figure and ground, or how form is arranged in three
- crucial organizing themes must be imposed on stimulus by the perceiver, so that, organization is "in the eye of
the beholder" and not stimulus itself
- addition, steps of organization not"add-ons"late in process
-organizing steps proceed in parallel with-and so can influence, be influenced by- very earliest "pick-up" of
information from stimulus.
- should also emphasize steps of perceptual organization matter for in many ways.
- (1) organization determines most immediate impressions of stimulus.
-stimulus we "see;' other words, as well as the stimulus appears to resemble, all determined not just by
pattern in front of our eyes, but by pat