Sensation & Perception Flashcards
sensation
the physical processing of environmental stimuli by the sense organs
perception
the psychological processing of interpreting sensory information
What is the process of sensation to perception?
stimulus → sensory receptors → transduction → neural impulses → perception
psychophysics
methods that measure the strength of a stimulus and the observer’s sensitivity to that stimulus
Who studied psychophysics?
Gustav Fechner
absolute threshold
the smallest amount of stimulation needed for detection by a sense 50% of the time
True or False:
lower absolute threshold = greater sensitivity
True
True or False:
Perception is an all-or-none phenomenon.
False
happens little by little
difference threshold/
just noticeable difference
the minimum difference between two stimuli needed to detect a difference between them 50% of the time
The more intense the original stimulus, the ___ the amount that needs to be added before a difference is detected.
larger
What is the JND?
original: loud music
change: volume up by 3
high
What is the JND?
original: quiet music
change: volume up by 3
low
top-down processing
when our perceptions are influenced by our expectations or prior knowledge
perception → sensation
bottom-up processing
when we receive individual pieces of sensory information and use them to construct a more complex message
sensation → perception
signal detection theory
a response to a stimulus depends on a person’s sensitivity and decision criteria
stimulus: present
response: present
hit
stimulus: absent
response: present
false alarm
stimulus: present
response: absent
miss
stimulus: absent
response: absent
correct rejection
What is the most favorable response in a high-stakes situation?
false alarms > misses
sensory adaptation
diminished sensitivity as a result of constant or recurring stimuli
What are examples of sensory adaptation?
- wearing perfume
- hearing an air conditioner
- being aware of wearing clothes
selective attention
focusing on one particular task or event over the full picture
inattentional blindness
failure to perceive objects that are not the focus of attention
change blindness
failure to detect changes to the visual details of a scene
cornea
transparent covering of the eye
pupil
opening in the eye through which light passes; dilates or constricts to let more or less light in
lens
focuses the eye
retina
light-sensitive lining of the eye
fovea
indentation in the center of the retina with the greatest visual acuity
What is the process of vision?
light enters eye → image projected on the retina → transduction → signal travels down optic nerve → thalamus → visual cortex
transduction
photoreceptors transform light into a neural signal through ganglion cells
normal vision
image focused perfectly on retina
near-sightedness
image focused in front of retina
far-sightedness
image focused past the retina
cones
responsible for color vision
rods
responsible for vision in low light
trichromatic color theory
3 different cones each sensitive to different wavelengths of light
RGB
opponent process theory
we perceive color in opposing pairs
* red/green
* yellow/blue
* white/black
How do negative afterimages work?
cells stimulated by a certain color are inhibited until the opposing color is no longer perceived
feature detectors
cells that respond selectively to specific features (i.e. lines)
How is information routed after the visual cortex?
through visual processing streams to other cortical areas
dorsal processing stream
“Where is it?”
sent to parietal lobe
ventral processing stream
“What is it?” / “Who is it?”
sent to temporal lobe
visual agnosia
inability to recognize objects
prosopagnosia
inability to recognize familiar faces
monocular depth cues
help us perceive depth using one eye
binocular depth cues
help us perceive depth using two eyes
retinal disparity
different images received by each eye based on different perspectives
convergence
when a person views a nearby object, eyes turn inward
constancy
our brain uses depth cues to keep our perception of brightness and size constant
Carpentered World Hypothesis
our experience with corners affects our depth perception
Point of Subjective Equality (PSE)
the point at which the two lines are seen as equal
Point of Objective Equality (POE)
the point at which the two lines are actually equal
pinna
outer part of the ear where sound waves enter
auditory canal
where sound waves are funneled through
eardrum
sound waves strike and cause the ear drum to vibrate
ossicles
tiny bones that amplify sound and transmit sound waves to the cochlea
cochlea
contains hair cells (auditory receptors) that vibrate the frequency of sound waves and turn them into nerve impulses sent to the auditory nerve
conductive hearing loss
damage to the eardrum or ossicles that lead to the failure to amplify sound
sensorineural hearing loss
damage to the cochlea or neural patheway that lead to failure to transmit neural signals to the brain
sound localization
location of sound determines the timing of when sound hits the left ear vs. right ear first
multimodal perception
effect that concurrent stimulation in more than one domain has on perception of events and objects
What is an example of multimodal perception?
hearing sound and watching a video at the same time
synaesthesia
condition in which perceptual or cognitive activities trigger exceptional sensory experiences
What is an example of synaesthesia?
seeing music notes as colors
