Chapter 3: Perception Flashcards
(29 cards)
What is sensation?
The process by which sensory receptors transduce physical stimulation in the environment into neural impulses.
What is perception?
The process by which sensory input is interpreted to form a meaningful subjective percept.
What is contralateral organization?
Stimuli on left side are projected to right side of brain, vice versa.
What is psychophysics?
The scientific study of how our subjective percept is related to the physical properties of environmental stimuli.
What is Fechner’s law?
Increase in stimulus intensity needed to perceive a change in intensity is proportional to original stimulus intensity.
What is contrast?
Difference in luminance between adjacent elements of a scene.
What does orientation refer to?
Direction information contained within an image.
What is spatial frequency (SF)?
Amount of detail in an image - variation in contrast per unit of space.
What is the contrast sensitivity function?
We do not perceive all spatial frequencies equally well.
What is depth perception?
Binocular disparity.
What is colour vision?
Different colours have different light wavelengths.
Short end - red, Long end - blue.
What is the processing hierarchy?
Basic visual features are processed hierarchically, with more complex features being extracted at higher levels of analysis.
What is context in visual processing?
Simple visual features -> object recognition -> knowledge.
What is colour constancy?
Differences in background illumination can ‘trick’ the brain.
What is figure-ground segmentation?
Despite ambiguity in the image, most people see an object against a background.
What is denotivity?
Features that are familiar and meaningful tend to be perceived as the foreground.
What are the two visual streams?
The ventral ‘what’ pathway extracts shape and texture information to identify objects; the dorsal ‘where’ pathway processes relevant spatial information for the purposes of guiding action.
What is visual agnosia?
A disorder in which a person cannot identify or recognize common visual objects.
Results from damage to structures within the ventral stream.
What is optic ataxia?
Could identify visual objects, but could not use visual information to guide behaviour.
What is the ventral stream?
Critical for object identification - intersection of vision and memory.
What is face perception?
Sub-regions within IT (i.e., fusiform gyrus) play an important role in face recognition.
Some sub-regions contain exclusively (~97%) face-selective cells.
What is the ‘Thatcher Illusion’?
A phenomenon related to face perception where faces appear different when inverted.
What is the dorsal stream?
Where pathway; thought to transform visual information for the purposes of action.
What are interactions between vision and action?
Our ability to act on the world influences the way we consciously perceive it.
