Unit 3: Sensation and Perception Flashcards
Sensation
Detect energy from environment and encode it as neural signals
Psychophysics
Study relationship btwn physical energy and psychological exp.
Stimulus
Environmental change able to be detected by sensory receptors
Absolute threshold
Smallest energy amount leading to reaction 50% of time
Signal detection theory
Ability to detect stimulus based on stimulus’ intensity and your physical/pyschological state
Difference threshold (just noticeable difference)
Smallest amount of change in stimulus that’ll produce a change in sensation
Weber’s Law
Harder to tell difference in stimulus when it’s louder, brighter, etc.
Subliminal Stimulation
Sensory info below person’s threshold for perception
Transduction
Transforms stimulus energy to electrochemical energy
Perception
Process organizing sensory input and makes it meaningful
Bottom-up processing
1st: sense stimulus
2nd: perceive and process exp.
Top-down processing
1st: perceive and process exp. (Expectation)
2nd: sense stimulus
Perceptual constancy
Ability to recognize object has not changed despite stimuli around it changed
Visual capture
Tendency to allow visual images to dominate our perception
Example: at movies we think the voices come from actors not speakers
Vision Process
Ray of light → cornea → pupil (where iris expand/contracts) → lens → retina (image formed)
Depth perception
Ability to judge objects distances
Monocular Cues
Distance cues based on 1 eye’s images
Interposition Overlap (Monocular Cues)
Closer object cuts off view of distant object
Relative Size (Monocular Cues)
2 same-size objects: closer one casts larger image on retina
Relative Height (Monocular Cues)
Objects closer to horizon appear farther away
Texture Gradient (Monocular Cues)
Closer objects have coarser, more distinct texture
Linear Perspective (Monocular Cues)
Cue to distance when parallel lines converge in distance
Example: sidewalks
Binocular cues
Distance cues based on 2 eye’s images
Convergence (Binocular cues)
Eyes move in for near object and straight for further object
Retinal Display (Binocular cues)
Images from each eye differ (disparity)
Schemas
Concepts or frameworks organizing and interpreting info
→ result from exp.
→ example: interpretations of ufo’s, loch ness, or cloud
Cornea
(Front of eye)
Bends incoming light rays
Iris
(Surrounds pupil)
Muscle regulating size of pupil opening
Pupil
(In Iris)
Small, adjustable opening that’s smaller in bright light, larger in darkness
Lens
(Behind pupil)
Changes shape (more spherical or flatter) to focus rays → image
Retina
(Back of eye)
Light-sensitive surface containing rods and cones that transduce light energy
Fovea
(Small area of retina)
Where cones are most concentrated
Optic Nerve
(Formed by ganglion cells)
Neural impulses from eye → thalamus
Photoreceptors
Neurons that convert light energy → electrochemical neural impulses
Rods
(Photoreceptor)
Defect black, white, and gray
Also detects movement
Cones
(Photoreceptor)
Detects color and detail in bright light conditions
Bipolar Cells
(retina’s 2nd layer of neurons)
Impulses from rods and cones → ganglion cells
Ganglion cells
(retina’s 3rd layer of neurons)
Forms optic nerve
Feature Detectors
Detects movements, shapes, and angles of certain stimuli
Hubel & Wiesel
Feature- detector theory: perceptions of stimuli constructed from neurons in brain sensitive to specific features of stimuli
Light Waves
Stimuli for receptor cells lining retina
Wavelength
Dertimines hue: ROYGBIV
→ short = cool (purple - 400nm )
→ long = warm (red - 650nm)
Amplitude (light waves)
Dertimines hue’s intensity
→ height of light wave
Trichromatic theory
Cones work in 3 teams (red, green, blue) → can make all colors → signal strength is how brain interprets color
→ light hits Retina → cones stimulated → color
Opponent-process theory
Visual info transferred from cones → ganglion cells (some neurons excited aka on, some off)
Neurons turn off and on during process
→ explains after images
Physical Illusions
Messes with depth perception
Physiological Illusions
Visual system overstimulated
→ exciting or fatiguing photoreceptors and feature detectors
Cognitive Illusions
Optical illusions
Audition
Hearing
Fechner
Established every 10dB corresponds with 10 times increase in volume
Amplitude ( sound waves)
Dertimines sound’s loudness (large amp. = large sound)
→ Sound wave’s height
→ measured in dB (decibles)
Frequency
Of completed wavelengths that pass a point in a second
Number of completed wavelengths that pass a point in a second
Pitch
A sound’s lowness or highness
→ short wavelength= higher frequency and higher pitch
→ long wavelength= lower frequency and higher pitch
Timbre
Sound quality determined by waveform’s purity
Outer ear (all parts)
→ Pinna
→ Auditory Canal
→ Eardrum
Auditory Canal (Outer Ear)
Where sound waves enter
Eardrum (Outer Ear)
Vibrates soundwaves
Middle ear (all ossicles)
All ossicles
→ Stirrup
→ Hamm er
→ anvil
The Ossicles
Eardrum cause ossicles to vibrate
→ vibrating (stirrup) pushes against cochlea
Inner ear (all parts)
→ Cochlea
→ Semicircular Canals
→ Vestibular Sacs
Basilar membrane
(Inside cochlea)
It’s hair cells are bent by stirrups vibrations and traduce mechanical energy → electrochemical energy
Also, hair cells synapse auditory neurons → auditory nerve
Sound localization
Determine sounds location
→ Parallel Processing: process both ears’ intensity and timing differences to determine location
Gustation
Chemical sense of taste
→ receptors on tongue, roof of mouth, and throat
Olfaction
Chemical sense of smell
→ receptors on mucous membrane and roof of nasal cavity
Somatosensation
Skin sensations
Gate-control theory
Pain experienced only if pain signals pass through gate in spinal cord → brain
Vestibular sense
Body’s sense of equilibrium
→ receptors in semicircular canals and vestibular sac
Kinesthesis
Body sense providing info about position and movement of individual parts
→ receptors in muscles, tendons, joints
