Lecture 3 Flashcards
What is the visual field
the range you can see without moving your eyes, 180 degrees to 190 degrees horizontal, 130 to 140 degrees vertical
Degrees of visual angle?
a way to talk about how big something is on the retina
Fovea:
rod free region of the retina
Perceptual bias and Hermann Von Helmholtz
cheat codes for your brain to understand the complex world
Our perception of the world is biased by what we think - from our experience of the physical world- of what is likely happening: the likelihood experience
Gestalt principles of perceptual organization
PPCCSG
Proximity: Objects that are close to one another appear
to form groups
Pragnanz (“good shape”): the tendency to reduce
complex patterns into easy to perceive forms
Closure: A tendency to perceive a complete figure even if
the figure is incomplete
Common fate: the tendency to perceive a group of
individual objects moving in the same manner as a unified
group
Similarity: Objects that share a feature (or more!) are
more likely to group with each other
Good continuation: The assumption that objects
continue behind occluders
Perceptual assumptions:
1) Light from above: our visual systems assume light sources are above us
2) Oblique effect: better at discriminating orientations that are close to horizontal or vertical
3) Face inversion: better at processing faces when they are upright then when they are inverted, Thatcher illusion: inverting the features within a face and then inverting the face only looks wrong when the face is upright
Expectations and simplifying the visual world:
1) Semantic violation:
2) Syntactic violation:
1) Semantic violation: objects appear out of context, but in a physically possible location (toilet paper in dishwasher)
2) Syntactic violation: objects appear in the correct context, but in impossible situations (toilet paper floating mid air in washroom)
Pop out search and Conjunction search:
Pop out search: does not matter how many distractors there are, completely parallel (do not have to look at each and every item) across the visual field
Conjunction search: have to go through a set of items before getting to the target Visual system breaks up input by feature
Conjunction search requires more information and the process is serial (going one by one through a subset of items) moving through each item in other words:
In feature search, whether the target is present does not matter
In conjunction search, you need to work through half the items to know
Scene grammar and Satisficing:
Scene grammar: Your expectation of the world, you learn to navigate the world, eg: looking for keys in toilet vs on hook
Satisficing: you do not have time to represent everything, you just need enough (minimal amount of information to do something in the world)
TVST ?
What and where on the brain is separate, Where is towards the Dorsal region and what is towards the Ventral region
