AP Psych - Sensation and Perception

selective attention

the capacity for reacting to selective stimuli when others are occuring simultaneously

inattentional blindness

• inabiity to see object/person bc of lack of attention
• ex. basketball gorilla

change blindness

when a change in object/enviroment goes unnoticed

sensation

the process by which our sensory receptiors and nervous system recieve and represent stimulus energies from our enviroment

perception

the process of organizing and interpreting sensory data

bottom-up processing

analysis that begins w/ sensory receptors and works up to the brain’s integration of sensory info

top-down processing

information processing guided by higher-level mental processes, constructing perceptions by drawing on our experiences and expectations

psychophysics

study of relationships btwn physical charactics of stimuli and our psychological experience of them

absolute threshold

minimum stimulation needed to detect a particular stimulus 50% of the time

signal detection theory

• predicts how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise)
• proved that there is no single absolute threshold and that detection varies bc of experience, expectations, motivation, and alertness

just noticeable difference (JND)

the amount something must be changed in order for a difference to be noticeable 50% of the time.

difference threshold

minimum required difference between two stimuli for a person to notice change 50% of the time

subliminial

below one’s absolute threshold for conscious awareness

priming

the activitation of certain associations, thus influencing one’s perception, memory, or response

Weber’s law

the principle that, to be percieved as different, two stimuli must differ by a constant proportion/percentage (rather than a constant amount)

sensory adaptation

• diminished sensitivity resulting from constant stimulation
• ex. nerve cells consistantly fire when clothing is initially put on, but after constant exposure, they fire less frequently

transduction

• conversion of one form of energy to another

• in sensation, the transforming of sights, sounds, smells into neural impulses

wavelength

the distance from the peak of one wave to the peak of the next

hue

• color (blue, green, etc.)
• determined by wavelength

intensity

• amount of energy in a wave (perceived as loudness or brightness)
• determined by amplitude

pupil

adjustable opening in center of eye through which light enters

iris

• forms colored portion around eye
• controls size of pupil opening

lens

• transparent structure behing pupil
• changes shape to help focus images on retina

retina

• inner surface of eye

• contains rods, cones, and neurons

accommodation

the process by which the eye’s lens changes shape to focus objects on the retina

rods

• detect black, white, gray
• necessary for peripheral/low-light vision

cones

• concentrated near center of retina
• fine detail and color

optic nerve

carries neural impulses from eye to brain

blind spot

point at which optic nerve leaves eye, creating a “_” bc no receptor cells are located there

fovia

• central focal point in retina
• where cones cluster

optic chiasm

place where some optic nerve fibers from one eye cross optic nerve fibers from the other eye

feature detectors

nerve cells that respond to specific features of a stimulus, like shape, angle, or movement

parallel processing

• processing many aspects of a problem simultaneously
• ex. vision (the brain delegates the work of processing color, form, motion, depth to different areas)

Young-Helmholtz trichromatic theory

• theory that the retina contains three different color receptors (one most sensitive to red, one to green, one to blue)
• when stimulated in combination can produce perception of any color
• supported by color-deficiency

opponent-process theory

• theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision

• supported by afterimage effect

audition

sense or act of hearing

frequency

the number of wavelengths that pass a point in a given time

pitch

• a tone’s highness or lowness
• depends on frequncy

middle ear

• chamber btwn eardrum and cochlea
• contains hammer, anvil, and stirrup
  • concentrate eardrum’s vibrations on the cochlea’s oval window

cochlea

• coiled tube in the inner ear
• converts sound waves into nerve impulses

inner ear

contains cochlea, semicircular canals, vestibular sac

semicircular canals

• inner ear
• fluid-filled tubes that help maintain balance

vestibular sacs

• inner ear
• react to gravity + movement

oval window

• end of middle ear/beginning of inner ear
• helps transmit vibratuons to cochlea

basilar membrane

• inner ear
• when oval window vibrates, ripples in the bend hair cells, which trigger nerve impulses

auditory nerve

sends neural messages to auditory cortex

place theory

in hearing, the idea that different sound waves trigger activity in different places, thus we determine pitch by recognizing the place generating the neural signal

frequency theory

in hearing, the idea the rate of neural impulses matches the frequncy of a tone, thus enabling us to sense its pitch

conduction hearing loss

hearing loss caused by damage to the system that conducts sound waves to cochlea

sensorineural hearing loss

hearing loss caused by damage to cochlea’s receptor cells or to the auditory nerves

cochlear implant

device that converts sounds into electrical signals which stimulate auditory nerve

kinesthesis

the system for sensing the position and motion of individual body parts

vestibular sense

sense of body movement and position, including balence

gate-control theory

theory that spinal cord cotains a neurological “gate” that regulates the passage of pain signals

process of smell

• scent molecules activate olfactory receptors
• signals travel up olfactory nerves to the olfactory bulb, then to brain via the olfactory tract

sensory interaction

principle that one sence may influence another

gestalt

• school of psychology
• “the whole is different that the sum of its parts”

figure-ground

organization of visual field into objects (figure) that stand out from surroundings (ground)

grouping

tendency to organize stimuli into coherent groups

• proximity - group nearby figures together
• similarity - group similar figures together
• continuity - perceive smooth, continuous patterns
• closure - fill in gaps to create complete, whole object
• connectedness - elements that are thought to be connected bc of colors, lines, etc.

depth perception

ability to see objects in three-dimensions despite the fact the the images percieved by retina are two-dimentional

visual cliff

laboratory device for testing depth perception

binocular cues

depth cues that depend on use of two eyes

• retinal disparity - images from the eyes differ, the closer the object, the larger the disparity
• convergence - eyes move inward for close objects

monocular cues

depth cues that require the use of only one eye

• relative size - distant image is smaller
• interposition - closer object blocks distant object
• relative clarity - hazy object is farther
• texture - course = close, fine = distant
• relative hight - higher objects seen as more distant
• relative motion - closer objects seem to move faster
• linear perspective - parallel lines converge w/ distance
• relative brightness - closer objects appear brighter

phi phenomenon

illusion of movement created when lights blink in quick sucession

perceptual consistancy

percieving objects as unchanging (having consistant shape, size, brightness, and color) even as retinal images change

perceptual adaptation

the ability to adjust to an artificially displaced or inverted visual field

perceptual set

a mental predisposition to percieve one thing and not the other

human factors psychology

a branch of psychology that examines how people and machines interact + how machines can be made safe and easy to use

extrasensory perception (ESP)

the claim that perception can occur without sensory input

• telepathy - sending/perceiving another’s thoughts
• clairvoyance - perceiving remote events
• precognition - perceiving future events

Earst Weber

• German physician

• Weber’s law - to be perceived as different, two stimuli must differ by constant minimum percentage, rather than a consistant constant

Gustav Fechner

• German psysicist, philosopher, experimental psychologist
• Weber-Fechner law

Thomas Young and Herman von Helmholtz

• proposed trichromatic theory
  • three different color receptors (red, green, blue)

Ewald Hering

• German physiologist
• opponent-process theory
  • opposing retinal processes (red-green, blue-yellow, black-white)

David Hubel and Torsten Wiesal

• discovered feature dectectors using anethetized cat

Kurt Koffka, Max Wertheimer, Wolfgang Kohler

developed Gestalt psychology