Ch.3 Perception Flashcards
Main Effects
Effect of one variable regardless of the effect of the other variable. Eg: Main effect of sleep: Greater sleep results in a higher grade.
Visual Perception Process
- Formation of proximal stimulus
- Meaningful interpretation of proximal stimulus to form precept. Recognizing/attaching meaning to the object. Shaped by cognitive processes
Active Participation in Perception
top-down processing involved in perception. (organize stimuli, group stimuli into coherent patterns/wholes
Interpret stimuli as consisting of objects and backgrounds.
Gestalt Principles of Perceptual Oganization
Interpret objects as wholes.
Follow certain principles in coming to interpretations
Unconscious processes
Most principles subsumed under the law of Pragnanz.
Law of Pragnanz
Select organization that yields simplest and most stable shape/form
Favors simple/symmetric forms (triangle)
Bottom-up Processes
Receiving and combining information to form precept
Fast-acting automatic processes that aren’t influenced by expectations/previous learning
Sequential processing.
Template Matching
Compare incoming pattern of stimuli with previously stored templates
Recognition by Components
Recognize the parts, infer the whole
Recognition of the whole object depends on recognition of its features
Recognition of phonemes (basic unit of sound) used to recognize all possible words
Biederman Recognition
Biederman (1987) proposed theory of object perception based on geons (2D/3D shapes)
Recognizing Letters by Features
Visual search task studies by Neisser (1963)
Time to detect Q or Z arrays
Letters in array share features (roundedness vs straight lines) with stimulus of interest.
Recognizing Phonemes by Features
Perceptual system becomes tuned to the phonemes (categorical sound distinctions of our language)
Babies initially notice more distinctions among sounds, then eventually become tuned to the distinctions present in their language (Eimas, 1985)
Categorical Perception
Lisker and Abramson (1970)
Categorical Perception implies top down processes
We can hear new distinctions between sounds when we learn a new language
Top-down processing does influence what we see/hear
Phonemic Restoration
An auditory illusion is where a missing speech sound that has been replaced by a non-speech sound is heard in a word. Top-down processing that can compensate for noisy speech input.
Effects of Language on Perception
We dissect nature along lines laid down by our native languages (Wharf, 1956)
Perceptual warping from labels. Stimuli in same category perceived as more similar. Better discrimination between stimuli for people who possess the lexical distinction than those who do not
Categorical Labels as Cues
Stimuli (colors) from different verbal categories discriminated faster than stimuli from the same category.
Visual Mismatch Negativity
Response to perceptual deviance between rare and frequent objects (eg: orange and red)
We will use simplified ERP (event related potentials) curves showing just component of interest
Categorical Perception of Objects influenced by Language
English has different verbal labels for “cup”/”mug”
Spanish has one verbal label “taxa”
Measure perceptual deviance between cups (standard) and mugs (deviant) in English and Spanish speakers
Strong response to rare (deviant) object of mug (English)
Muted response to rare (deviant) object of mug (Spanish)
Language Influences Object Perception
Different verbal labels (cups/mugs) allow English speakers to differentiate between 2 types of objects
Spanish speakers the 2 types of objects are more perceptually similar because the verbal label is the same (taxa)
Prototype Matching
Prototype: Idealized representation of some class of objects.
Allows for variation between perceived object and prototype. The greater the feature overlap between object and prototype, the closer the match.
Posner and Keele (1968)
1st Phase: Participants learned to categorize images that were distorted versions of prototypes (didn’t see prototypes)
2nd phase: participants shown old distortions, new distortions and prototypes and asked to categorize them.
Old distortions: 87% accuracy
New distortions: 67% accuracy
Prototypes: 85% accuracy
In phase 1, participants formed mental representation of each class of items (prototype)
Word Superiority Effect
Conceptually driven, directed by expectations from context/past learning (interact with bottom-up processing)
Word Superiority Effect (Reicher, 1969): Letter identified more accuractely when embedded in a word.
Influence of context (word) on the perceptual experience of the letter
Model of Word Recognition (McClelland/Rumelhart 1981
Incorporation of top-down processing (use of context) with bottom-up processing (feature detection)
In written text (rather than individual words) the influence of word on letter detection depends on the role of a word in the text.
Content words (carry meaning) facilitate letter detection
Function words (of, for) may inhibit it
Face Perception
Thought to be holistic process (eg: Gestalt Process)
Composite faces: cannot see that top half is identical
Offset faces: can see top half is identical
Response to the whole face, not its components
Prosopagnosia
Typically results from brain damage
May have intact object recognition abilities
Identify features (nose, eyebrow) but cannot put them together in a whole face
