Week 4 Flashcards
What is prosopagnosia
Cognitive disorder of face
perception
* Difficulty perceiving/recognizing
faces
* Face blindness
* Intact vision
What is sensation
Detection of physical energy by the sense organs
What is perception
The brain”s interpretation of raw sensory data
Sensory receptors
specialized neurons that
respond to different
types of stimuli
What is photoreception
Light
What is mechanoreception
pressure, vibration, movement
What is chemoreception
Chemical
What is transduction
Conversion of one energy form into another
What is bottom-up
perception based on
building simple input into more complex perceptions
What is top-down
a perceptual process in
which memory and other cognitive
processes are required for interpreting incoming sensory information
What happens during sensory adaptation
Sensory receptor cells become less responsive to a stimulus that is
unchanging, becomes less noticeable
What is psychophysics
Measurement of sensation
What is the absolute threshold
Minimum intensity of a stimulus that a person can detect half the time
What is subliminal perception
Perception of stimuli
that are presented at
below absolute
threshold
What is the JND
The degree of difference that must exist between two stimuli before the difference is detected
What is Weber’s Law
JND between 2 stimuli is not an
absolute amount, but an amount relative to the
intensity of the first stimulus.
- The more intense the initial stimulus, the larger the
difference needs to be
What is selective attention
Focusing on a specific aspect of sensory input while ignoring other
stimuli in the environment
- Attention as bottleneck
- The other channels are still being
processed at some level
What is inattentional blindness
- Failure to detect an
unexpected stimulus in
plain sight - Limited attentional
resources, focus on
what we deem
important
What is change blindness
- Failure to detect changes in
your environment - Limited resources further
constrained by… - Age
- Distraction
What is vision
starts with light, the physical energy that stimulates the eye
What is transduction (vision)
photoreceptors (rods & cones)
The iris
muscle ring that controls
pupil size
* Controls amount of light
entering eye (via the pupil)
Cornea & lens :
Light enters through cornea, passes through pupil, and hits lens
- Lens: Focuses light rays into image on eyeball’s retina
Retina
light-sensitive back
inner surface of eye – nerve
cells here!
* Contains rods & cones
What is the optic nerve
carries neural impulses from eye to brain
Blind spot: point where optic nerve leaves the eye, no receptor cells
Which part of the eye constricts with disgust when youre about to say no
the iris
What are rods & cones
Retinal receptors
Rods (100-125 mil): detect
black, white, and gray and are
sensitive to movement
* Peripheral & twilight vision
* Low light situations
* Located in periphery
Cones (5-6 mil): sharp focus, colour perception, detail
* Work well in daylight
* Cluster around fovea
What are feature detectors
cells in visual cortex that respond and are sensitive to specific features of env’t
- Some cells respond to lines in
specific orientations - Simple cells – lines, angles
- Some cells respond to particular
shapes (e.g., bulls-eyes, spirals,
faces)
What is the trichromatic theory
retina contains red, green & blue receptors –
when stimulated, these receptors can produce perception of any
colour
- Consistent with three types of cones in eyes
- Explains colour blindness BUT not afterimages
What is opponent process theory
we perceive colours in terms of three pairs of opponent colours: red or green, blue or yellow, and black or white
Which theories does colour processing combine
the trichromatic theory and the
opponent processing theory
What can blindness result in ?
Blindness can result in reorganization of other sensory cortices and changes in other senses (i.e., compensation)
* Echolocation might improve following blindness
What is visual agnosia
object recognition deficit: damage to higher visual cortical areas
What is blindsight
above-chance visual performance of cortically blind
individuals with damage to area V1
What is perceptual organization
We don’t passively respond to visual
stimuli that fall on the retina, we actively try
to organize and make sense of what we see
What is gestalt principles
Principles that determine how we organize infromation into meaningful wholes
What is perceptual constancy
The recognition that objects are constant and unchanging even
though sensory input about them is changing
What is colour constancy
The ability to perceive an object as having relatively the same
colour under varying illumination conditions
What is monocular depth
Relies on one eye
- Relative size
- Texture gradient
- Overlap
- Shading
- Height in field of view
- Linear perspective
What are binocular depth cues
Requires both eyes..
Convergence and disparity
How does culture shape visual attention
East Asians &
European/North
Americans process
visual information
differently!
* Eastern à holistically
(context &
relationships)
* Western à analytically
(salient objects)
What is sound
is movement of air molecules brought about by vibration of
an object
What is the outer ear (pinna )
Reverse megaphone – funnels sound in toward
eardrum
What is the eardrum (Tympanic membrane)
- Part of the ear that vibrates when sound waves
make contact - Transmits vibrations to middle ear
What is the middle ear
Tiny chamber containing 3 tiny bones (stirrup, anvil, hammer) that act as mechanical amplifier
What is the cochlea
- Coiled tube in ear filled with fluid that vibrates in response to sound
What are hair cells
- Tiny cells that are bent by vibrations – transmit neural message (transduction
happens here!
What is basilar membrane
Runs through center of
cochlea – divided into two chambers, covered with hair cells
What is conductive deafness
Malfunctioning of the ear especially a failure of eardrum or ossicles
What causes nerve deafness
Due to damage to auditory nerve
Nerve induced hearing loss
Damage hair cells due to repeated loud noises
What is bottom up processing
Begins with sensory receptors
We sense basic features of stimuli and integrate them
What is top down processing
- Guided by higher-level mental processes
- Previous experience and expectations are used to interpret what senses detect
What are perceptual sets
Predisposition or readiness to perceive something in a particular way (top down influence)
What is Synesthesia
Stimulation of on sense evokes another,
Sounds with colour, colours with taste
