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Feature Theories: Distinctive Features Models

Hubbel 7 Wiesel (1962): recorded electrical activity in the visual cortex of the cat. Turnbull (1961): BaMbuti Pygmies. Kenge: Lived all their lives in the forestExposed to plain Savannah no trees! (could not understand)?Blakemore

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Feature Theories: Distinctive Features Models

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    1. Feature Theories: Distinctive Features Models Discriminate stimuli based on a small characteristics Involves listing individual features that a pattern has Breaking down a pattern into smaller parts Distinctive features helps distinguish patterns as different Physiological Evidence (Hubel & Weisel,1965): Cats respond neurally to vertical & horizontal lines Single cell recordings show that neurons in cats are sensitive to lines at different orientations

    3. Hubbel 7 Wiesel (1962): recorded electrical activity in the visual cortex of the cat

    5. Turnbull (1961): BaMbuti Pygmies Kenge: Lived all their lives in the forest Exposed to plain Savannah no trees! (could not understand)? Blakemore & Cooper (1970): Raised Cats in dark and exposed to vertical or horizontal lines When taken out of dark: Those exposed to vertical lines reacted only to vertical & ignored horizontal lines

    6. Psychological Evidence Gibson, Shapiro, & Yonas (1968): Step 1: Analyze letters in terms of small set of features Step 2: Test (RT) if two letters are same or different G vs. W RT = 468 ms P vs. R = 671 ms (Share too many features?!!)? Step 3: Compare the clustering of letters in the reaction time task to the similarities in features

    10. Feature Theories Pandemonium (Miller & Selfridge)? Cognitive Hierarchy Bottom-up Processing Demons

    11. Pandemonium Once upon a time there was Pandemonium. In Pandemonium there dwelt many very ugly and intelligence challenged (a.k.a. stupid) demons. There was only one little hole to look out of and only one demon could look out of it. This image demon could only paint what he saw and show it to the demons in the row standing behind him. The demons in the next row, being of stout body and little brain, could each only recognize one type of feature. Since there was little else to do in these cramped quarters, the feature demons got excited and jumped up and down if they recognized their feature. The demons in the row behind them were unable to see the painted image because they were too dumb or scared to turn around and were facing the wrong way. Each of the cognitive demons, however, were connected to specific feature demons by ropes. Based on the elasticity of the ropes, which varied, the cognitive demons would get painful tugs from their connected feature demons. The resulting shrieks from the row of cognitive demons were louder from the demons who had more of their connected feature demons excited. Finally, there was the grand high decision demon who really just wanted quiet. Upon hearing the calamity from the cognitive demons, the decision demon would yell out the name of the cognitive demon shrieking the loudest (with a threat to make him turn around and look at his brother demons – a fate worse than death)?

    14. Feature Theories Problem: Don't explain how features of a pattern are organized.

    15. Recognition-by-Components (Beiderman, 1995)? Assumption: Recognition of 3D objects involves the use of 24 3D shapes (GEONS--for Geometrical Ions)? A variation of Feature-Comparison Model, but for 3D objects Research has generally supported the theory Problem: People poor at identifying objects in unusual angles or orientations

    17. Structural Theories Theories to explain how the Relationship or Grouping of features make-up a pattern Extension of Feature Theory: Perceive the features organize them. Analysis By Synthesis (Neisser)? Involves a synthesis of information from what is being perceived and what the perceiver expects to see From research on letter scanning: Scan a page full of letters for one particular letter

    18. Structural Theories Template theory would predict that total time would be a function of the number of letters scanned Neisser found that the non-target letters influenced scanning time the most (Angular letters vs. Rounded) Easier to find the letter when the non-target letters were of a different type

    22. Top-Down vs. Bottom-Up Process Bottom-Up Processing: Information processed at the lower levels without influence from higher levels Processing language from the lowest level to the highest level (from the acoustic signal to phonemes to words)? TULIPS = FLOWER TULIPS = TWO LIPS TU (~2) LIPS (as in kiss).

    24. Top-Down vs. Bottom-Up Process Top-Down: Information at the higher levels may influence processing at the lower levels (i.e., lexical information influences the choice of phoneme)? Processes also involved in “guessing” and predicting: Walking down the ________? John Doe is a very nice individual (HE/SHE/THEY) is always very nice.

    30. New Orleans: As rain from Hurricane Rita Threatened to once again floop the city, the Army corps of Engineers was racing to patch the New Orlean's fractured levee system while residents were forced to decide yet again whethel to stay or go. Forecasters said the storm that swiped Florida on Tuesday could strengthen to Catedoy four and hit Texas by the end of the week. But a slight turn to the right was possible and engimeers feared additional rain could swamp the city's levees.

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