AP Psych Vocab - Unit 3 - Sensation and Perception

sensation

the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

perception

the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

bottom-up processing

mental processing that starts with sensory input that the brain attempts to understand or make sense of

top-down processing

mental processing that is guided by experience and higher-level mental processes; we often see what we expect to see based on experiences that have impacted our psychology

selective attention

focusing conscious awareness on a particular stimulus (the brain can only process so much information at one time and thus cannot apply focus uniformly)

dual processing theory

the theory that information is simultaneously processed on two different tracks: the slow, effortful, conscious track and the quick, automatic, unconscious track

cocktail party effect

being able to pay attention to only one voice among many sounds, or being able to detect your name in a voice you’re not necessarily paying attention to; an example of selective attention

inattention blindness

failing to visible objects when our attention is directed elsewhere

change blindness

failing to notice changes in the environment

choice blindness

failure to recall a choice immediately after you made it

process of converting energy within our brain

receiving sensory stimulation via specialized receptor cells, transforming that simulation into neural impulses, and delivering the neural information to the brain

transduction

conversion of one form of energy, such as light waves or sound waves, into another form, like neural impulses that our brain can interpret

psychophysics

the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them

crossing the threshold of a stimulus

crossing the point at which a stimulus is strong enough to be noticed (conscious awareness)

absolute threshold

intensity needed to detect a particular stimulus (light, sound, pressure, taste, odor) 50 percent of the time

subliminal

stimuli you can’t detect 50 percent of the time; below your absolute threshold for conscious awareness

signal detection theory

a theory predicting how and when we detect the presence of a weak signal amid background noise; the idea that there’s no single absolute threshold and that detection is influenced by experience, expectations, alertness, motivation

priming

a technique in which the introduction of one stimulus influences how people respond to a subsequent stimulus

difference threshold (just noticeable difference)

the minimum difference a person can detect between two stimuli 50 percent of the time; the ability to tell the difference between stimulus intensity levels; increases with the size of the stimulus

weber’s law

a law that states that in order to be perceived as different, two stimuli must differ by a constant minimum percentage (not amount)

sensory adaptation

diminished sensitivity to stimuli as a consequence of constant stimulation; nerve cells fire less frequently and free our attention to focus on new stimuli

perceptual set

a mental predisposition to perceive (top-down processing) one thing and not another, often influenced by context, culture, or motivations

cornea

the eye’s clear, protective outer layer covering the pupil and iris; light enters the eye first through this

pupil

a small adjustable opening in the center of the eye through which light passes

iris

a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening by expanding or contracting over the pupil.

lens

a transparent structure behind the pupil that changes shape to help focus incoming light rays into images on the retina

accommodation

a process involving the lens changing its curvature and thinkness, focuses rays of light onto the retina

retina

the light-sensitive inner surface of the eye, containing the photoreceptor rods and cones plus layers of neurons that begin the processing of visual information

rods

a type of retinal receptor cell; detect black, white, and gray and are sensitive to movement; necessary for seeing in dim light and for peripheral vision; do not have a direct hotline to the brain (share bipolar cells and send combined messages)

cones

a type of retinal receptor cell; detect fine detail and create color sensations, function in daylight or in well-lit conditions (unresponsive in dark, we don’t see color in a dark room); have a direct hotline to the brain and relay individual messages (exclusive input)

fovea

cones cluster in and around this area; the central focal point of the retina

blind spot

the point at which the optic nerve leaves the eye, creating a blind spot because no receptor cells are located there

bipolar cells

cells in the visual system that connect the photoreceptors (rods and cones) to the ganglion cells

ganglion cells

specialized neurons located in the retina at the back of the eye; receive signals from bipolar cells and transmit them through their axons

feature detectors

specialized neurons in the visual cortex that receive info from individual ganglion cells in the retina; respond to shape (lines/edges), angle, movement

parallel processing

brain cell teams in different areas of the brain unconsciously process combined information about motion, form, depth, and color all at once

visible light spectrum

the portion of the electromagnetic spectrum visible to human eyes

wavelength

determines the color of light (ROYGBIV) or the pitch of a sound (high or low); the distance from the peak of one wave to the peak of the next

amplitude or intensity

determines the loudness of a sound (e.g. a yell or a whisper) or the brightness of a color (neon vs. muted); the height of a wave

Young-Helmholtz Trichromatic Theory (Thomas Young and Hermann von Helmholtz)

the theory that retina contains 3 different color receptors (cones sensitive to red, green, or blue), and that when stimulated in combination, they produce the perception of any color

Opponent-Process Theory (Ewald Hering)

the theory that opposing retinal processes allow for color vision; neurons work in pairs to process color vision signals (red-green, yellow-blue, white-black); some neurons are turned “on” by red but turned “off” by green

gestalt

meaningful categories developed based on a human tendency to organize pieces of information we get from our senses

figure-ground gestalt

an organization of the visual field into objects (the figures) that stand out from their surroundings (the ground)

grouping

the tendency to organize stimuli into coherent groups

proximity grouping

the grouping of nearby figures together

similarity grouping

the grouping of similar items together

continuity grouping

the perception of a smooth or continuous pattern, a form of grouping

closure grouping

the mental filling in of gaps to create a complete or whole object, a form of grouping

common region grouping

the grouping of certain items together if they’re located in the same bounded area

depth perception

a mental ability that allows us to judge distance

visual cliff

a structure made by Eleanor Gibson and Richard Walk (1960), indicated that biologically we are predisposed to be wary of heights; and experience can also increases that cautiousness

binocular cues

depth or distance cues that depend on the use of both eyes

retinal disparity

a binocular cue for perceiving depth where the brain compares images from the two eyes to compute distance; the greater the disparity between two images the closer the object

convergence

muscle movements in our eyes providing information about how deep or far away something is

monocular cues

depth cues available to each eye separately

relative size

a monocular cue; if two objects are similar in size, we perceive the one that casts a smaller retinal image to be farther away

interposition

a monocular cue; objects that block other objects appear as closer

relative height

a monocular cue; perceive objects higher in our field of vision as farther away

linear perspective

a monocular cue; parallel lines appear to meet in the distance; affects perceived distance

light and shadow in vision

a monocular cue; shading produces a sense of depth consistent with our assumption that light comes from above

relative motion

a monocular cue; as we move, stable objects seem to move with us

phi phenomenon

an illusion of movement created when two or more adjacent lights blink on and off in succession; we construct the motion in our heads

motion clue for perceiving motion

the perception that shrinking objects are moving away and enlarging objects are approaching us

perceptual constancy

a top-down process that recognizes objects without being deceived by changes in their color, brightness, shape, or size

color constancy

perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object (red apple on sunny and rainy day)

perceptual adaptation

the ability to adjust to changed sensory input, including an artificially displaced or even inverted visual field (e.g. goggles that shift the world right, left, or upside down); we are disoriented first but adapt over time

pitch

a tone’s experienced highness or lowness; based on its frequency

ossicles

the bones of the hammer, anvil, and stirrup; detect vibrations and transmit them to the cochlea

auditory canal

the outer ear canal; where sound waves enter and travel through to the eardrum

cochlea

a coiled, fluid-filled tube that converts sound vibrations into electrical signals that can be interpreted by the brain

eardrum

a tight membrane that vibrates when in contact with sound waves; transfers the vibrations to the ossicles

basilar membrane

a thin strip of tissue within the cochlea that contains the hair cells which operate as the sensory receptors for the auditory system; the movement of the hair cells triggers electrical impulses

Place theory (Hermann von Helmholtz)

the theory of audition that states pitch is determined by the location of vibration along the basilar membrane, and that different sound waves trigger activity at different places along basilar membrane; does not account for low-pitched sounds as they do not appear at a consistant place along the basilar membrane

Frequency theory (William Rutherford)

the theory of audition that states that the brain reads pitch by monitoring frequency of neural impulses traveling up the auditory nerve; increased frequency of sound waves causes an increase in the perceived pitch

volley principle

the principle that accounts for an issue with the frequency theory; nerve cells have to alternate firing to create a perception of a high pitch if the sound wave is above 1000 Hz

sensorineural hearing loss

caused by damage to the cochlea’s receptor cells (hair cells) or to the auditory nerve, also called nerve deafness; can be treated with a hearing aid or cochlear implant

conduction hearing loss

caused by damage to the mechanical system that conducts sound waves to the cochlea; can be treated with a surgical implant of an artificial bone

sensation of touch

a mix of skin senses for pressure, warmth, cold and pain

Gate Control Theory (Ronald Melzack and Patrick Wall)

the theory that spinal cord contains neurological “gates” that either block pain or allow it to be passed on to brain

olfaction

the sense of smell; odor molecules bind to smell receptor cells, directly send signals to brain (bypass thalamus) where they get interpreted in olfactory cortex

gustation

the sense of taste; papillae (bumps on tongue) contain taste buds that have taste receptor cells (gustatory cells) that sense food molecules

kinesthesia

the system for sensing the position and movement of individual body parts; sensors in joints, tendons, and muscles

vestibular sense

sense of whole body movement and position, including sense of balance

semicircular canals

connected to the cochlea, contains fluid that moves when your head rotates or tilts, stimulates receptors that send messages to cerebellum to perceive balance

embodied cognition

the idea that bodily sensations can affect cognitive processes like judgement, preference and memory