PSY280 - 5. Object Recognition Flashcards
Spatial Rule
stimuli presented close together in space tend to be integrated
hear a sound + see something at same time - link it to single event
if at diff locations, don’t see it as single event
Temporal Rule
stimuli presented close together in time tend to be integrated
no integration when stimuli presented at vastly diff times
hear creak + door opens, doesn’t make sense unless simultaneous
Inverse effectiveness
effect of integration is more pronounced with weaker
stimuli
bigger enhancement of perception when dealing with degraded intensity
Multisensory Integration improves
detection
response times: faster to respond when presented in 2 modalities
accuracy: various judgements of stimulus when more than 1 presented
fundamental attributes
defer to vision for judgments about space, to hearing for judgments about time
to identify 2 objects - have to be separated in space
tend to assume auditory stimulus at the location of visual event
Middle vision
stage of processing that comes after basic features & before object recognition or scene
house recognition: mix of complex processes that allows us to recognize it
this is the object, other is the background
Where are the edges?
How can we tell that car & house separate objects?
How can we tell that snowman & house are separate objects?
How can we tell that the windows & the house are part of
the same object?
Where are the edges?
decide where 1 object ends + another 1 behind cell identifies lines
we identify objects because continuous + connected
connectedness can’t answer snowman because they’re connected
we know windows + house are same objects, yet they’re connected
some objects overlap
Connectedness won’t work
Connectedness isn’t even necessary
continuous edges aren’t necessary for our system to perceive edges
visual system fills in gap
we perceive more contrast than actually there
Even if connectedness did
work, what are the
important edges?
we tend to see objects in contexts
our visual system not challenge to find boundaries even if there are multiple edges
illusory contours
don’t even need edges to perceive segregation
contour that is perceived even though nothing changes from 1 side of the contour to the other
illusory contours perception without sensation
Structuralism
perceptions result from summation of many elementary sensations
Gestalt
wilhelm wudnt - complex objects/perceptions can be understood by analyzing components
Structuralism
components = elementary sensations
couldn’t explain illusory contours or apparent motion
elementary sensations of apparent motion that structuralism couldn’t explain
Structuralism
flashing stationary light moving on + off giving illusion of movement
more + more perceptual phenomenon that structuralism couldn’t explain
Gestalt
whole is different than sum of it’s parts
direct response to structuralism
heuristics used to guide interpretation of retinal image
sometimes >1 principle at work - difficult to predict which one is going to win all else being equal
Gestalt
Gestalt principles are like individuals with opinions
about how the information should be organized
under diff conditions, diff principles/rules might have diff opinions
Gestalt
discuss how to organize sensory input into coherent sensory experience
perception by committee - a consensus does quickly emerge that allows us to settle on a single interpretation of a visual scene
gestalt principles
- simplicity: assume simplest structure - simpler to see it as
- similarity: tend to group together stars + circles
- proximity: 3 groups of 2 lines
gestalt principles
- common fate: movement in the same direction
5. closure: things close shaped tend to be grouped together/close objects that are incomplete
gestalt principles
- familiarity: 45 means something to us - then we see us
- good continuation
- similarity: all orange dots, proximity: close together
gestalt principles: good continuation vs. similarity
When 2 principles operating, it’s hard to predict which one takes precedence.
general assumption that smooth lines belong together + lines tend to follow smoothest path
not strict rules, just heuristics
but if good continuation vs similarity pitted against each other, similarity wins
similarity has it’s limits
similarity has limits: works for colour, shape, size, orientation
but combo of these features doesn’t work too well
perception by committee
diff rules can come together + our perceptual experience isn’t always clear about which one wins
middle vision = specialists, diff in opinion about what sensory input might mean
how to organize info through committee
Pandemonium Model
Despite the potential for disagreement, there are some basic committee rules - example of how to implement computer vision model
Image demons like scanners: get sensory info
passes to first level of analysis: feature demons like specific features - cheer when preferred feature is present
