Chapter 4- Recognizing Objects Flashcards
Apperceptive Agnosia:
Able to see object’s shape, colour, and position, but can’t put these elements together to perceive the whole object
Associative Agnosia:
• Able to see but can’t link what they see to basic visual knowledge
i.e. Ability to pick up glove and describe it, but doesn’t know that it is a glove, “the man who mistook his wife for a hat”
Integrative Agnosia:
Able to detect features in a display
Impaired when they need to judge how features are bound together to form complex objects
Combination of both apperceptive agnosia and associative agnosia
Bottom Up Processes:
Processes that are directly shaped by the stimulus
Top Down Processes:
Processes shaped on your knowledge
Identification of Visual Features:
Input pattern (lines, curves…etc) assembled into a large unit • i.e. 4 right angles= square People are faster at detecting/ analysing simple features than a combination of complex ones
Tachistoscope
Device designed to present stimuli for precisely controlled amounts of time
Post stimulus mask
Random assortment of letters to interrupt any continued processing of stimulus to be sure that the stimulus was presented for only a controlled amount of time
Word Frequency and Word Recognition:
Frequently viewed words and infrequently viewed words for 35 ms followed by mask. Frequently recognized words recognized twice as much
Priming:
Exposure to a stimulus beforehand
Repetition priming
○ Exposure primes participant for second exposure
i.e. Participants read list of words aloud, then shown series of words in tachistoscope (some were in the previous list). Words that were primed had a higher recognition rate)
Word Superiority Effect:
Words are easier to perceive than isolated letters
Two alternative, forced choice procedure
○ Letter presented with post stimulus mask, then ask participant what letter it was (give them 2 choices)
○ Word presented with post stimulus mask, then ask participant what letter was in display (2 choices)
Accuracy was much higher in word condition
Degree of Well Formedness:
How well a letter sequence conforms to usual spelling patterns
i.e. JPSRW is harder to remember than FIKE
Making Errors:
Strong tendency to misread less common letter sequences as if they were more common patterns
i.e. TPUM more likely to be read as TRUM or DRUM or TRUMPET
Feature Nets:
Network of detectors, organized by layers
Bottom layer is concerned with features (i.e. horizontal lines)
Each layer deals with larger scale objects
Demonstrates bottom up processing
Detectors:
Each detector has an activation level, which reflects how energized the detector is
Activation level increases when detector receives input until it reaches its response threshold causing t to fire (send its signal to other detectors)
Detectors that have fired recently or frequently will have a higher activation level- weak signal is enough to make them fire
