perception Flashcards
perception
- interpreting/understanding/putting signals into context
- cues do not differ from different senses and their cues
_____ take in neurotransmitters and leave from ______
dendrites, axons
order the eyes structure from front to back
cornea, iris, pupil, lens, fovea, retina, optic nerve
define cornea, iris, lens, and retina
- cornea: clear covering to the eye
- iris: ring of muscles controlling how much light gets in
- lens: w/cornea, focuses light on back of the eye
- retina: where sensing takes place, photosensitive membrane at the back of the eye where transduction takes place
Define fovea and optic nerve
- fovea: point of highest visual acuity, centre of retina, focal point (surrounding is blurry)
- optic nerve: takes visual info to the brain
The point where the optic nerve leaves the eye is known as the ______
blind spot
changing of physical stimulus into neural energy/electrical signal
transduction
where does transduction take place in the eye
two places in the retina:
- rods: bright/dim, sensitive to light but poor acuity
- cones: colour, low sensitivity to light, high acuity, diff types respond to diff colours
why do eyes constantly move
because photoreceptors need replenishing/to reset constantly
perfectly functioning eyes but damage to one of the occipital lobes results in _______
- blindsight
- due to multiple paths for visual info, they can guess the right answer unconsciously
Distal vs proximal stimulus
Distal: stimulus out in the world, 3D object
Proximal: stimulus on the sense organ, 2D representation on the retina
examples of binocular cues
- convergence (focused on a point close to the eyes, gives idea of distance, eyes converge and lens accommodate when objects are close)
- Binocular disparity: slightly different view angles of the world projected, shows sense of how far your retinas are, gives idea of depth
t or f: the brain uses info from both eyes (binocular cues) and not properties from the proximal stimulus (monocular cues) to make inferences about depth of distal stimulus
false, the brain uses both together
what do monocular cues do and what are they based on
- based on info from one retina
- makes inferences on size/distance
Monocular cue: Perspective
- lines converge at a distance
- ex. train tracks disappearing in distance/two lines looking different sizes bc of track size or arrow pointing to or away
Monocular cue: Relative size
bigger things tend to be closer
Monocular cue: Interposition
- closer objects obscure/overlap distant ones
- front is closer
Monocular cue: Motion parallax
- close= quick, far=slow
Monocular cue: Texture gradient
- less detailed=farther away
Monocular cue: Ariel perspective
- farther something is, the more of a haze to it (often blueish)
Monocular cue: shading
- shadows/shading shows cues about depth/gives illusion of height
Monocular cue: Light and shadow
- light source us assumes to come from above
- faces are assumed to be convex
Your knowledge of the world and matching info with what you already know is described as ______
object perception
Gestalt Psychology
- assumptions made in order to process info
- how we segregate and group visual info
- ‘The whole is more than the sum of the parts’ - interpretation is key
Gestalt principals: Law of proximity
- group things together the closer they are
Gestalt principals: Law of similarity
- group things together based on visually similar stimuli
Gestalt principals: Law of good continuation
- how you extract parts of an object even if the object is covered/disrubted
Gestalt principals: Law of closure
- illusory contours
- inferences made due to seeing an image
- implying contour
- seeing a shape/picture based on lines/surrounding shapes/lines
Gestalt principals: Law of common fate
- different small sections are seen as part of object bc they move similarly (speed, pattern, etc)
- ex bird flocks
Gestalt principals: Law of pragnanz/simplicity
- organizing visual display should be as simple, stable, and consistent as possible
- interoperate the world as simple
- gravitate towards simple explanations
- ignore hard things
Bi/monocular cues are innate assumptions about _______
3D objects
Bottom up Theories vs top-down theories
bottom up: decision based on info coming in, data-driven (external stimuli>sensory info>perception)
top down: use knowledge/context when info comes in to understand/process, conceptually driven (world knowledge>expectations and biases>perception)
Template theory
- objects have templates that you compare current images to, you have a copy of everything you’ve encountered and match it when you reencounter it
- object must be: same size and position as template
- no room for variety, 1:1 match (even though same thing can have different interpretations
Feature theory
- more flexible
- certain neurons respond to features
- recognize object by searching memory for objects with those features
- analyses objects as combo of elemental features
- Findings by Hubel and Weisel showing we have cortical cells that react to specific features
For feature theory, how do feature detectors work
- order: word detector, letter detector, feature detector
- neurons feed into other neurons until they combine to form info (building blocks)
How did Selfridge adapt the feature theory in an easy to understand way
- Pandemonium (how info gets from outside world to your head for processing)
- Uses ‘demons’ who shout at different volumes
- order: data, feature, cognitive, decision demons
t or f: exaggerated facial features lead to faster recognition
true
Prototype theories
- overall representation of new and old info line up
- a prototype is the one ‘ideal’ for a category, takes all interpretations and makes the average
- room for variety
- perceive object by comparing it to stored prototypes
- may not differentiate different items within a category (ie. cat breeds)
bi stable images
- you either interoperate it one way or the other (never both at once)
What is a modified version of feature theory
-Object centred theories
- representations one has is based on the object itself
- features are 3D and more complex
- feature positions relative to other features
Who was a key player in object centred theory and what did they study
- Biederman
- Recognition by components
- every object is build up of 3D ‘geons’
- if you recognize components, you recognize the object
t or f: according to Biederman’s research on object centred theory, it is easier to recognize objects when parts are missing rather than line segments
no, line segments removed rather than parts missing
What is the modified template theory and what does it say
- Viewer centred theory
- info based on incoming processing
- every experience with an object is stored until you use it later
- multiple snapshots of objects stored
t or f: you can match new incoming stimuli to make a new angle of an object according to viewer centred theory
true
What is the theory of being able to rotate stimulus to match with previous exposure and who thought of it
- Tarr
- Multiple view theory
- under viewer centred theory
t or f: research by Tarr and Gauthier show that multiple views of the same object learned are stored together
false, the different views are stored separately
when talking about multiple view theory, does one:
a) Have a 3D map of all objects from their previous perceptions
or
b) Take a snapshot of the object and do the 3D transformations in their head
b)
Thomas Bayesian’s Theory of Object Recognition
- make assumptions based on priors
- probability not absolutes
- (generative model) incoming stimuli> break down into features)>priors>(recognition model) belief abt features>belief abt objects
what are priors (bayesian)
- expectations for what youre seeing
- gets modified by experience
What is change blindness
- when people do not notice changes in environment bc attention was not directed there
flicker paradigm
- gone or there, easy to spot difference
name the gestalt principals
- law of proximity
- law of good continuation
- law of similarity
- law of closure
- law of common fate
- law of simplicity
