Unit 3: Sensation - vision，hearing Flashcards
Sensation
is the process by which we receive information from the environment
Stimulus
Detectable inputs from the environment
Threshold
minimum stimulus intensity needed to produce a sensory response
Transduction
converting energy of a stimulus into neural activity
Absolute Threshold
minimum stimulation needed for detection ~50% of the time
Subliminal Stimuli
Not conscious of the stimuli
Subliminal
Not conscious
Difference threshold (Just Noticeable Difference JND )
minimal change in stimulation that can be reliably detected 50% of the time
Weber’s Law
Difference thresholds differ by a constant percentage rather than amount
Difference thresholds grow with the magnitude of the stimulus.
Signal Detection Theory
Predicts that we will detect a minimal stimulus (signal) among other background stimuli (noise)
Motivation, experience, expectations, physical state affect detection of weak stimuli
(Sensory) Adaptation
Constant Stimulus → Decreased Response
constant level of stimulus results in decreased response over time
Retina
cells capture visual information → transduced to brain for processing
photosensitive surface at back of the eye
Accomodation
Lens focuses visual stimuli on retina
retina
Two types of photoreceptors
RODS & CONES
cones
stimuli in the center of the visual field are detected mainly by color-sensitive cones concentrated in the fovea
Cones see Color，彩色
rods
stimuli at the edges of the visual field are detected mainly by non-color-sensitive rods in the periphery of the retina
黑白颜色
Gestalt closure
Brain’s visual system fills in the gaps
farsightedness
远视， 难以看清近处的物体
nearsightedness
difficulty in seeing objects far away
近视
Prosopagnosia
face blindness
Blindsight
unconscious ability to respond to visual stimuli without conscious awareness
Young-Helmholtz Trichromatic Theory
Retinas contain three types of cone cells, each responding best to a particular wavelength of light
蓝 waves short high / medium waves 绿/ 红 long low
Opponent Process Theory
Red vs. Green
Yellow vs. Blue
Black vs. White
Thalamus: some neurons turned on/off by “opponent” color
Pitch
different wavelengths
Loudness
different amplitudes
Place Theory
Differences in pitch result from stimulation of different areas of the basilar membrane.
Frequency Theory
Differences in pitch are due to rate of neural impulses traveling up the auditory nerve
Volley Theory
Neural impulses are too slow for highest pitches
↳ Group of neurons take turns (“volley”) to match highest frequencies
Sound Localization
how we identify where sounds in our environment are coming from
Conductive deafness
Causes: tumors, objects in ear canal, infections, otosclerosis (genetic, degeneration of the middle ear bones)
sound waves are unable to be transferred from outer to inner ear
Sensorineural deafness
Causes: infections, genetic defects, exposure to loud noises, trauma, high blood pressure, diabetes, MS
damage to the inner ear or auditory nerve leading to the brain
Non-tasters
unable to taste chemical PROPylthioracil (bitter)
Medium tasters
average # of taste buds, can taste PROP
Super tasters
high # of taste buds; highly sensitive to tastes (& PROP)
olfactory bulb
Olfaction (Smell)
Olfactory epithelium: thin membrane in upper nasal cavity
Only sense to not go through thalamus
Sensory Interdependency
sensory systems work together, not independently
↳ without smell → taste sensation muted/not experienced
Kinesthesis
Communicates information about movement & location of body parts
Vestibular Sense
Sense of balance and knowledge of body position
Gate control theory
spine
Pain messages from the body travel along a set of spinal cord nerve fibers
大脑每次只能集中注意力于一个疼痛刺激
Phantom Limb
sensation that an amputated/missing limb is still present
Perception
is the process of selecting and identifying information from the environment.
Selective attention
ability to focus on one stimulus while excluding other stimuli that are present
Cocktail party effect
where people attend to mentions of their names/specific topics in loud/distracting environments
Inattention/Change Blindness
changes to the environment are not perceived due to inattention
ingroup-outgroup bias…
we focus more on those in our in-group and less on individuals not in our group
Bottom-up processes
Identify a stimulus by information from external stimulus
Top-down Processes
Uses internal or prior experiences to identify stimuli
Use internal prior expectations to identify
identifying a stimulus by using the knowledge we already possess about the situation
Sensory Adaptation
Decrease in perceptual response (inward or outward movement) to a given stimulus
Gestalt Psychology
Perceptual principles help explain how humans organize their perceptual world
Visual Perceptual Constancies
maintain the perception of an object even when the images of the object in the visual field change.
Size, Color, Brightness, Shape
Phi Phenomenon
Apparent movement can be visually perceived even when objects are not actually moving.
Retinal Disparity
The slight difference in the images perceived by the left and right eye
Monocular Depth Cues
Visual cues that help us perceive depth and distance with only 1 eye
Figure ground
Tendency to organize the visual field into object that stands apart from surroundings
Convergence
a binocular cue for depth perception that helps us determine how close or far an object is.
Proximity
Grouping things based on how close they are to each other
Relative clarity
Helps us judge distance. Objects that are closer seem shaper and objects that are further seem blurry
Interposition
Something blocks the view of something in the back
Similarity
Grouping things based on how similar they are to one and another
Linear perspective
Converging of parallel lines in the distance
