Intro to Cognitive Science - Unit 2 Flashcards
What prior element contributes to our perceptions?
Our expectations of what we should be perceiving (34)
What wavelengths of light are visible to humans?
400-700 nm (35)
Which eye structure contains photoreceptors?
The retina
Which two eye structures work together to bring an image into focus?
Cornea and lens
Where does detailed vision occur?
In the fovea of the retina
Where are neural signals in the retina sent?
To the lateral geniculate nucleus of the thalamus
What kind of sensory input does the thalamus receive?
Auditory, visual, other, etc.
Where does the visual neural signal go after the lateral geniculate nucleus of the thalamus
To the primary visual cortex in the occipital lobe
Where is the primary visual cortex?
Occiptal lobe
By which hemispheres are visual inputs to the left and right eyes processed?
By both, no matter which eye (36)
What happens at the optic chiasm?
The nasal (only the nasal) optic axons cross over to the other side (36)
Why does the optic chiasm function as it does?
So that objects in the LVF are processed by the RH, and objects in the RVF are processed by the LH (36)
Where do 20% of visual signals leaving the retina go?
The superior colliculus (38)
Superior colliculus
Top of the midbrain, controls eye movements (38)
Do all visual signal pathways terminate in the primary visual cortex?
Nope, to be explained later :P (38)
What structure is essential to visual consciousness, besides the functional retina, optic nerve, and lateral geniculate nucleus?
Primary visual cortex in the occipital lobe (38)
What kind of cells are specifically needed for visual awareness?
Cortical cells that have consistently been stimulated to the type of vision (38)
What did the “D.B.” experiment prove?
The occipital primary visual cortex is essential to visual awareness, regardless of vision capability (39)
What did the horizontal/vertical kitten experiment prove?
That during the “critical period,” the visual cortex cells must receive stimulation in order to achieve visual awareness (38)
What is blindsight?
Vision without awareness as a result of lesions in the occiptal cortex (39)
How does perception begin?
With the transduction of physical energy to an initial neural representation of the stimulus (60)
What does pattern recognition mean?
The step between transduction and perception of a stimulus in the environment and its categorization as a meaningful object (40)
What does the ability to perceive depend upon?
Pattern recognition: recognizing the same object’s patterns in a variety of ways: eg: dogs from different angles (41)
What is agnosia?
When a person can see an object, but not recognize it or categorize it (41)
Appercertive agnosia
Object recognition fails as a results of difficulties in identifying the visual features that define a perceptual category (41)
What part of the brain is required for perceptual categorization?
The right posterior hemisphere (42)
Associative agnosia
Object recognition fails due to difficulties in identifying the functional features that define a semantic category (42)
Cane, closed umbrella, and open umbrella: describe the reactions of the perceptive agnosia and associative agnosia.
Perceptive: open and closed umbrella have same function; Associative: can’t identify that the open and closed umbrella have same function because cane and closed umbrella look similar (42)
What do the two types of agnosia demonstrate?
That pattern recognition involves two levels of categorization: 1) visual features must be matched to long-term memory images to identify perceptual categories; 2) the functional features must be matched to long-term memory representations to identify semantic categories (42-3)
What brain area mediates perceptual categorization?
Posterior regions of right hemisphere (42)
What brain area mediates semantic categorization?
Left hemisphere (43)
schema
Mental representation that organizes knowledge about related concepts (43)
top-down processes
Conceptually-driven
What do top-down processes do?
reduce the need to sample all info available: provides expectations (43)
bottom-up processes
Data-driven
What do bottom-up processes do?
Allow analysis of the “edges, lines, areas of light and dark, colors, sounds, and other physical features available briefly in sensory memory” (43)
How do data-driven and conceptually-driven processes interact?
Conceptually-driven provides and expectation, and data-driven picks up info to confirm or refute the expectation (43)