M2 Lecture 9: Feb 12 Flashcards
Perception involves what
figuring out which interpretation of the reality is the most likely
what is The pandemonium model of perception
demons represent neurons, and each level is like a brain area.
Committees must integrate conflicting opinions and reach a consensus.
what are The Four steps of sensation and perception
physical stimulus–> 1. transduction –> 2. transmission –> 3. perception
what is modulation
Cognitive factors, like expectations, attention, etc. will influence how sensations are perceived.
e. g. Top-down vs bottom-up processing
e. g. Bayesian prediction process
what are the Committee rules in the pandemonium model
- Put together what goes together (ex.: Gestalt grouping rules)
- Avoid accidents (ex.: accidental viewpoint)
- Honour physics (ex.: occlusion)
4, Reach consensus (ex.: ambiguous figures) - Separate what should be separated (ex.: figure vs ground)
what i
what is Accidental viewpoint
A viewing position that produces some regularity in the visual image that is not present in the world.
(like the 3d paintings on roads that look like such from a certain angle but completely warped from other angles)
what is Occlusion
solid objects block light
what is Figure-ground assignment
The process of determining that some regions of an image belong to a foreground object (figure) and other regions are part of the background (ground).
what are the 5 main Gestalt figure-ground assignment principles
surroundedness size symmetry parallelism Extremal edges
what is Surroundedness:
The surrounding region is likely to be ground.
what is Size:
The smaller region is likely to be figure.
what is Symmetry:
A symmetrical region tends to be seen as figure.
what is Parallelism:
Regions with parallel contours tend to be seen as figure.
what is Extremal edges:
If edges of an object are shaded such that they seem to recede in the distance, they tend to be seen as figure.
what is Structuralism
Dots make lines -> lines make corners -> corners make shapes -> shapes are connected one to another and make objects.
what is the formula for perception
structuralism + committee rules = object perceived
what is the Face inversion effect
We are better at recognizing faces that are upright.
Logically, it seems that object recognition should follow figure-ground assignement, but then it shouldn’t matter if the face is up or down….
Object recognition also helps with what
figure-ground assignement.
is perception just a feed forward process
It cannot all be a feed-forward process, there has to be reciprocal communication between object recognition and figure-ground assignement.
what is the Global superiority effect
The properties of the whole object take precedence over the properties of parts of the object
(aka you see the ‘H’ that the small ‘s’s’ make instead of just the small ‘s’s’
HOW DO WE RECOGNIZE OBJECTS ?
2 attempted ways to tackle it:
Naïve template theory
Structural description
what is Naïve template theory:
The proposal that the visual system recognizes objects by matching the neural representation of the image with a stored representation of the same “shape” in the brain
do Naïve template theory work
Naive template theories don’t work
what is Structural description
maybe what we recognize is a particular organisation of simpler features?