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Sensation and Perception 1

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sensation
Process where sensory receptors and nervous system receive and represent stimulus energies from the environment
Perception
the process of organizing and interpreting sensory information
Bottom-up processing
processing that begins with the sensory receptors and works its way up
Top-down processing
processing that uses previous experiences to understand new ones
Selective attention
the focusing of conscious awareness on particular stimuli
Cocktail party effect
The ability to listen to a voice and block out others
Flow experience
Being so caught up in an experience that one misses out on obvious stimuli
inattentional blindness
Failure to see visible things when mind is elsewhere
change blindness
Failure to notice changes in the environment
choice blindness
people fail to notice choices they made
pop out stimuli
powerful stimuli that draw attention
psychophysics
study of the relationship characteristics of stimuli and how we experience them (s & p)
Gustav Fechner
studied absolute thresholds
absolute threshold
minimum amount of stimuli needed to detect something over 50% of the time if no other stimulus exists
signal detection theory
Detecting a stimulus also depends on physical and psychological state
Subliminal stimulation
Stimulation below the threshold. Any affect is only short term.
difference threshold
minimum difference that a person can detect between two stimuli
Weber's law
To be observed as different, proportion not amount is constant
Fechner's law
an increase in physical magnitude provides smaller increases in perceived magnitude
Sensory adaptation
diminishing sensitivity to an unchanging stimulus. Constant exposure to a stimulus causes neurons to fire less frequently
Vision
Our eyes receive light energy and transduce into a neural message for the brain
light's wavelength determines___
Color
light's intensity determines___
Brightness
Cornea
Part of eye that protects it and bends light to provides focus
lens
behind pupal; adjusts focus onto retina
retina
multilayered tissue on eye's inner surface
order light hits eye
cornea, pupal (surrounded by iris), lens, retina: rods and cones, bipolar cells, ganglion cells.
iris
colored muscle that adjusts light intake
Ganglion cells
axons form optic nerve
blind spot
where the optic nerve leaves the eye
cones
color sensitive, clustered around retina center, connected to individual bipolar cells.
fovea
most sensitive area on the eye
rods
not in center, not as detailed, not to individual bipolar, not affected by darkness, don't see color
feature detection scientists
David Huble and Torsten Wiesel
feature detection
these are individual cells that respond to specific parts of visual cortex (edges, movement, angles, etc.) pass info to association areas where it is integrated
order brain processes info
retinal processing (rods + cones, bipolar, ganglion), feature detection, parallel processing, recognition
optic nerve sends info to___
Thalamus
Parallel processing
brain cell teams (association areas) process combined info from feature detectors
Recognition
brain interpreted constructed image based on info from stored imagery. The end result is the scene.
Young-Helmholtz theory
our eyes have red, blue, and green cones and use these to make the rest of the colors
Trichromatic theory
same as the young-Helmholtz theory
Opponent process theory scientist
Ewald Henry
Opponent process theory
we also have red/green and blue/yellow cones.
Afterimage
After looking at a red thing for too long, red portion of rods get exhausted. Then on a paper you see green.
amplitude of a sound wave determines___
Loudness
Frequency of a sound wave determines___
pitch
pinna
outer ear, channels sound waves to auditory canal and ear drum
eardrum
vibrates when struck with soundwaves
3 small bones
hammer, anvil, stirrup
purpose of 3 small bones
the vibration causes a piston they create to to transmit sound waves to cochlea in inner ear
vibrations effect on cochlea
oval window of cochlea vibrates which jostles the basilar membrane
auditory nerve formed by___
axons of neurons in basilar membrane
basilar membrane
contains tiny hairs which send impulses when bent
Loudness perception
based on number of hair cells activated
place theory scientist
Herman Von Helmholz
Place theory
Sound waves of different frequency trigger hairs in different areas. Only works for high pitched sound.
Frequency theory
brain develops frequency by monitoring frequency of impulses traveling up auditory nerve. Neural impulses travel at same rate as basilar membrane vibrates, same as sound wave.
individual neuron maximum firing time
1000x/sec
Volley principal
neural cells alternate firing and achieve a higher frequency if used in combo
Locating sounds
closer ear hears more intense sound, and hears it sooner
Conduction Hearing loss
problems in mechanical systems that conducts sound waves to cochlea (ruptured eardrums, broken ear bones)
Sensorineural hearing loss
aka nerve deafness. damage to cochlea's hair cell receptors or associated nerves (hearing aid no help)