Sensation and Perception Flashcards
Response Bias
tendency of subjects to respond in a particular way due to non-sensory factors
Smell
- also comical sense (molecules of stimulus actually have to come in contact with receptors)
- receptors: located in olfactory epithelium (upper part of nasal passage)
- smell travels to olfactory bulb in the brain which is connected to amygdala and hippocampus which is why smell is connected to memory
Wever and Bray
Proposed volley theory of pitch perception in response to criticism of the frequency theory of perception
iris
- colored part of the eye
- has involuntary muscles and nerve fibers
- controls the pupil (and therefore the amount of light entering the eye)
Figure vs. Ground
- Figure: object that stands out at the center of attention in the visual field
- Ground: the background
- they can change! (ex: face vase illusion)
Vestibular Sense
- has to do with our sense of balance and bodily position relative to gravity
- semicircular canals in inner ear (above and behind cochlea) hold receptors for balance
Habituation
- research method for studying visual perception in infants
- a stimulus is presented to an infant and they eventually stop attending to it; a different stimulus is presented and if the infant attends to it, then it is inferred that the infant can perceive the difference between the two stimuli
Auto-kinetic Effect
- when viewed in a dark room, a stationary point of light appears to move, probably because of involuntary eye movements
Proprioception
- general term for our sense of bodily position; includes aspects of both vestibular and kinesthetic senses
E. Gibson and Walk
Developed the visual cliff apparatus, which is used to study the development of depth perception (experiments done on infants and animals)
Signal Detection Theory
- suggests that other, non sensory factors influence what we sense (factors include things like experiences, motives, and expectations)
- gives us a way to measure both how well subjects can sense stimuli (sensitivity) and response bias
- basic signal detection experiment: stimulus is either presented or it isn’t. Trials where it is NOT presented are called noise trials (or catch trials); trials where it is presented are called signal trials. Subject is asked to indicate whether or not a stimulus is presented.
- Four possible outcomes: Hits (++), Misses (+-), False Alarms (-+), and Correct Negatives (–)
- responses are graphically summarized by ROCs
Touch
- four broad categories: pressure, pain, warmth and cold
- at least 5 different tyoes of receptors:
1) Pacinian Corpuscles (displacement of skin such as deep pressure or vibration)
2) Messiner Cospuscles
3) Merkel Discs
4) Ruffini Endings
5) Free nerve endings - information processed in somatosensory cortex in parietal lobe
Trichromatic Theory
- aka Young-Helmholtz Theory
- suggests that the retina contains three different kinds of cones (color receptors), each of which is maximally sensitive to one of the three primary colors (green, blue, or red)
- light hits the retina and these three types of cones are stimulated to varying degrees. it is the RATIO of this activity that determines color.
- Young showed that you could mix the three primary colors and produce all of the other colors on the spectrum
- EXTRA Q: Where else do we see Helmholtz?
- developed place resonance theory of pitch perception
Distal vs. Proximal Stimulus
- distal: actual object or event out there in the world
- proximal: information our sensory receptors receive about the object
Fechner’s Law
- derived from Weber’s Law
- purpose: to relate the intensity of the stimulus to the intensity of sensation.
- determined that sensation increases more slowly as intensity increases
Gate Theory of Pain
- Melzack and Wall
- theory that there is a gating mechanism in the spinal cord that turns pain signals on and off
Shape constancy
- tendency for the perceived shape to remain constant regardless of variations in the retinal image
- ex: we see a door as rectangular even when as we open and close a door its retinal image can be anywhere between a line and a trapezoid
Moon Illusion
- also has to do with size constancy
- the moon looks bigger when on the horizon then when up in the sky (at its zenith*) despite the fact that the moon is the same size in both scendarios
- because on the horizon we have things to compare it too but we dont in the sky (relative size to buildings / etc. vs. to the blank sky)
temporal fibers
- fibers from temporal half of retina (away from the nose, closer to the temples)
- these do not cross over
ciliary muscles
- control the lens, allow it to accommodate in order to focus an image on the retina
Four Visual Constancies
- size constancy: tendency for the perceived size of an object to remain constant despite variations in the size of its retinal image
- shape constancy: tendency for the perceived shape of an object to remain constant despite variations in the shape of its retinal image
- lightness constancy: tendency for the perceived lightness of an object to remain constant despite changes in illumination
- color constancy: tendency for the perceived color of an object to remain constant despite changes in the spectrum of light falling on it
Taste
- chemical sense; molecules of stimulus actually have to come in contact with receptors
- receptors are tastebuds held in the papillae (little bumps on the tongue)
- information is sent to taste center in thalamus
Photoreceptor cells
- rods and cones
- responsible for sensory transduction through the chemical alteration of photopigments
Gestalt laws of perception:
1) Proximity: elements close to one another tend to be perceived as a unit
2) Similarity: objects that are similar tend to be grouped together
3) Good Continuation: tend to perceive continuous patterns in stimuli rather than abrupt changes
4) Closure: tend to be perceive figures as complete, and will even fill in gaps / perceive figures as more complete (or closed) then they really are
5) Prägnaz: encompasses the other laws; says that perceptual organization will always be as regular, simple, and symmetric as possible.
Cocktail Party Phenomenon
- you could be having a conversation with someone and totally tuned in but still hear your name from across the room in another conversation
Hering
Developed opponent process theory of color vision
J. Gibson
Studied depth cues (specifically texture gradients) that help us to perceive depth
Receiver Operating Characteristic (ROC) curve
- used to graphically summarize a subject’s responses in a signal detection experiment
- refined by Swets
Emmert’s Law
- describes the relationship between size constancy and apparent distance
- later generalized into size-distance invariance principle
- says that size constancy depends on apparent distance. the farther away an object appears to be, the more the scaling device in the brain will compensate for its retinal size by enlarging our perception of the object
Broadbent
Proposed filter of attention theory which argued that attention was an all-or-nothing process (which has now been proven to be incorrect)
Binocular Disparity
- binocular depth cue (requires both eyes)
- distance between the two eyes make our eyes see slightly different pictures of the world, degree of disparity between the two eyes is called binocular parallax
- when our brain combines these two images we get STEREOPSIS
- 10% of the population cant take advantage of this so rely on monocular depth cues
- use stereoscopes (tool) to research this (give impression of depth to a flat picture by presenting the eye with slightly different images like they would get in 3D)
Fovea
- mid section of the retina, contains only cones
- as you move farther away from retina, number of rods increases and number of cones decreases
- most sensitive in normal daylight vision
- visual acuity is best here
Duplexity (or duplicity) theory of vision
- states that the retina has two kinds of photoreceptors (rods and cones)
Single-cell recording
- used by Hubel and Wiesel to measure cell responses for Feature Detection Theory
- method involves placing a microelectrode (so small that the tip cannot be seen with an ordinary microscope) in the cortex so sensitive that it could record responses of a single cell.
- sometimes called “recording from single nerve fibers”
Light is composed of:
photons and waves; measured by brightness and wavelengths
Theory of Isomorphism
- suggests 1-to-1 correspondence between the object in the perceptual field and the pattern of stimulation in the brain
- hasn’t fared well empirically but sometimes appears on the test
Important factors in Brightness Perception:
- (dark) adaptation: regeneration of rhodopsin in rods (from bleaching), allowing you to see better in darkness. takes time, which is why it takes a second to adapt to a dark room such as a movie theater.
- lateral inhibition: adjacent retinal cells inhibit one another; sharpens and highlights borders between light and dark areas
Illumination vs. Brightness
Illumination is a physical, objective measurement that is simple the amount of light falling on a surface. Brightness is the subjective impression of the intensity of light stimulus.
Auditory Projection areas in the Brain:
- superior olivary complex
- inferior colliculus
- medial geniculate nucleus (in thalamus)
- temporal cortex
Projection Areas
brain areas that further analyze sensory input
cornea
- clear protective coating on outside of the eye
- gathers and focuses incoming light
Difference Threshold
how different two stimuli must be (in magnitude) before they are perceived as different
related to JND