Perceiving Objects Flashcards
Large lesions of temporal love including amygdala produce this
Psychic Blindness
Gradient flow
closer objects seem to move faster than distant objects
Psychic blindness a syndrome that includes__, responding to visual objects inappropriately
Visual agnosia
The inability to recognize faces is called__
And results from damage to the __ area in the human cortex
Prospagnosia, fusiform facial
Studies using __ show that activity in this area is highest when __ are presented
FMRI, familir
Studies using __ show that cells in a nearby area respond best to __ faces.
(Kobe Bryant)
Electrophysiology, particular
Studies have shown that some cells in the __ area of the monkey cortex respond most strongly to __ stimuli, a feature that helps discriminate a figure from ground-Gestalt theory
V4, Concave
Fusiform face area
Small circle spots within Inferotemporal cortex.
Location
Cells in the V4 of the monkey cortex
-on the border between occipital and temporal lobes
Response
Either to convexity or concavity,
Features which help discriminate figure from ground according to Gestalt Psychology
Ventral pathway
Flows through V2 and eventually into the temporal lobe and is concerned with object identification and color pereception
Kluver bucy Syndrome
-removal of temporal lobe including the amygdala
-psychic blindness, responding to visual stimuli inappropriately, suggesting lack of recognition
Object Agnosia
-removal limited to the lower temporal lobe, sparing the amygdala
-failure on the object discrimination task
Results of the Harrison Ford experiment
High response for FFA= correct recognition
Second highest= seen a face but incorrectly identified it
Lowest response= not seeing a face
FFA shows a selective response to familiar faces rather than all faces, but may not discriminate among equally familiar faces
Results. Of the kobe bryant experiment
-gma cella exist in medial temporal lobe
-single cell recordings in the medial temporal lobe of epileptic patients being preped for electrolytic lesions yo prevent the spread of seizuress
-one cell responded to images of kobe bryant but not other people
-another cell responded to the image of the Golden Gate bridge but not the leaning tower of pisa
-consistent with monkey single cell evidence
Bottom up form perception
-features extracted from the environment by receptors
-combined into more complex representations by the brain and then
-recognized through memory
-reductionist approach to perception
-physiological methods
Primary-dorsal pathway-frontal cortex
Challenges to Bottom up Theory
Illusory contours:non existent edges perceived
Feature detectors can’t detect them
Other processes contribute to perception
Gestalt Theory/ Top-Down perception
Evidence for active form perception
1. Separate stimulus into figure and ground
2. Determine figure using group rules
(Continuation, proximity,similarity,common fate, symmetry, closure)
Different types of cones are stimulated by different__ in the ___ spectrum
Wavelengths, electromagnetic
According to __ theory, there are __ kinds of comes maximally sensitive to __ respectively.
Trichromatic, 3 , blue-green-red
The phenomenon of __ suggests that there are ___ types of color sensitive cells, each of which is influenced by __ pairs of colors, according to the ___ theory
Afterimages, 6, complimentary pairs, opponent processing theory
When light that stimulates cells of one type is turned off, cells of a different type are ___ resulting in the perception of a color that isn’t physically present
Excited
Properties of Light
-Visible light is part of electromagnetic spectrum
-some animals can see energy in other parts of the spectrum(dog/cat/bird)
-it travels in waves
-Blue light= short wave, Red light= long wave, white light= combination of all wave
Additive color mixing
Occurs when new colors are made by the combination of different colored lights
-examples are stage lighting, tv screen, computer
-absorbs light dont emit them
-mixing red blue green( because any color can be matched by mixing them)
-perceived light=mixed wavelength
Subtractive Color Mixing
-what happens when mixing paint (blue and yellow)
-mixing paints w/ different pigments
-additional pigments=fewer wavelengths
-Mixing blue and yellow leads to green
Color matching experiment
Observer adjusts the amount of three wavelengths in one field so it matches the test patch color of the single wavelength in the other field
Trichromatic theory of color vision
-3 types of color receptors with different spectral sensitivities
-short wave=Blue(400nms)
-medium wave=Green(500nms)
-long wave=Red(675nms)
Psychophysical basis of the trichromatic theory
-Issue:Determining # of color receptors without physiological tools
-since people with normal vision need only 3 wavelengths to match all wavelengths in the spectrum
-color vision depends on 3 different receptor mechanism
Physiological Trichromatic Evidence
-color perception is based on the response of the 3 different types of cones
-3 different absorption spectra
-combinations of the responses across all 3 cone types lead to perception of all colors
Psychophysical basis of the opponent processing theory
-people who are color blind to red are aslo color blind to green
-people who are color blind to yellow are also color blind to blue
Opponent processing theory
-after image: a visual image in the complementary colors of the original image
-complementary colors produced gray when mixed together
-Opponent theory: cells make antagonistic responses to pairs of complementary colors (yellow-blue, red-green, black-white)
Cones follow trichromatic theory, cells higher up in the system follow the opponent processing theory
Theories that explain mechanism of retina
Trichromatic theory explains the responses of the cones in the retina
Theory that explains mechanism of cells connected to cones
Opponent process theory explains neural response for cells connected to the comes further in the brain
Theory that explain after images
Opponent disinihibition
Some info about depth or distance can be detected by using only one eye. These include ___ cues which allow us yo perceive three dimensions on surfaces with __ dimensons
Pictorial cues, two