Myers Unit 4, AP Psych - Sensation & Perception

Sensation

Sensation

A process in which the sensory receptors & nervous system receive and represent sitimulus

Perception

A process of organizing & interpreting sensory information, enabling us to recognize meaningful objects & events

Bottom-up processing

Analysis that begins with the sensory receptors, and works up to the brain’s integration of sensory information

Top-down processing

Info processing guided by higher-level mental processes; constructs perceptions from sensory input by drawing on our experience & expectations

Selective Attention

The focusing of conscious awareness on a particular stimulus

Cocktail party effect

The ability to attend to only 1 voice among many, while also being able to detect your own name

Inattentional blindness

Failing to notice changes in the environment

Choice blindness

Failing to recall a choice immediately after making said choice

Transduction

The conversion of one form of energy to another; in sensation, the transforming of stimulus energies into neural impulses our brain can interpret

Psychophysics

The study of physical characteristics of stimuli & their relationships, such as their intensity & our psychological experience of them

Absolute threshold

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

Gustav Fechner

Proposed the concept of absolute thresholds

Signal detection theory

Predicts how & when we detect the presence of faint stimulus amid background stimulation; assumes there is no single absolute threshold, & that detection depends on a person’s experience, expectations, context, motivation, & alertness

Subliminal stimuli

Stimuli below one’s absolute threshold for conscious awareness

Priming

Activation, often unconsciously, of certain associations, thus predisposing one’s perception, memory, or response; shows that we can process SOME info below our absolute threshold for conscious awareness, however, the effect is too fleeting

Difference threshold

The minimum difference we can discern between 2 stimuli 50% of the time; we experience this as a “just noticeable difference”

Weber’s Law

A principle stating that in order to be perceived as different, 2 stimuli must differ by a constant minimum PERCENTAGE, NOT a constant AMOUNT

Ernst Weber

Created Weber’s Law

Sensory adaptation

Diminished sensitivity as a consequence of constant stimulation; we become less aware of constant stimulus because our nerve cells fire less frequently because of it

Perceptual set

A mental predisposition to perceive one thing & not another; psychological factors that determine how we perceive our environment: expectations, context, culture, emotions, motivations, etc.

Schema

Our learned concepts thru experience that prime us to organize & interpret unclear stimuli in certain ways

Extrasensory perception (ESP)

A controversial claim that perception can occur apart from sesnory input; includes testable forms of telepathy, clairvoyance, and precognition

Parapsychology

The study of paranormal phenomena, including ESP & psychokinesis

Telepathy

Mind-to-mind communication

Clairvoyance

Perceiving events beyond the physical realm: past & future

Precognition

Perceiving future events

Bluish color waves

Short wavelength & high frequency - vision

Reddish color waves

Long wavelengths & low frequency - vision

Bright colors

Great amplitude

Dull colors

Small amplitude

Wavelength

The distance from the peak of one light or sound wave to the peak of the next; responsible for sight and audition

Hue

Dimension of color determined by wavelength of light

Intensity

Amount of energy in a light or sound wave which we perceive as brightness or loudness, as determined by a wave’s amplitude

Amplitude

The distance from rest to crest in a wave; determines the brightness or dullness of certain colors

Cornea

Protects the eye & bends light to provide focus

Pupil

Adjustable opening in the center of the eye where light enters

Iris

A ring of muscle tissue that forms the colored portion of the eye around the pupil; controls the size of the pupil opening

Lens

Transparent structure behind the pupil; changes shape to help focus images on the retina

Retina

The light-sensitive inner surface of the eye; contains receptor rods & cones & layers of neurons that begin the processing of visual info

Accommodation

The process where the eye’s lens changes shape to focus near or far objects on the retina

Receptor Rods

Retinal receptors at the back of the retina; detect black, white, & gray (grayscale); necessary for peripheral & twilight vision when the cones don’t respond

Cones

Retinal receptors that are concentrated near the center of the retina; function in daylight or well-light environments, detecting fine detail and giving rise to color sensation

Photoreceptors

Specialized cells at the back of the retina that transduce light into signals for the brain to process

Bipolar cells

Cells in the retina that connect photoreceptors to ganglion cells; help activate ganglion cells

Ganglion cells

Cells in the retina that receive visual info from the photoreceptors via the bipolar cells; pass information to the brain

Optic nerve

Bundled axons of the ganglion cells; a nerve that carries neural impulses from the eye to the brain and visual cortex (via the thalamus)

Blind spot

The point where the optic nerve leaves the eye, creating a spot where there are no receptor cells

Fovea

The central focal point in the retina, around where the eye cones cluster

David Huber & Torsten Wiesel

Psychologists who received the Nobel Prize for their work on feature detectors

Feature detectors

Nerve cells in the brain/visual cortex that respond to specific features of visual stimuli

Supercell clusters

Respond to more complex patterns; located in critical brain areas; info is passed onto them by feature detector cells

Face recognition area

Area in the right temporal lobe right by the right ear

Parallel Processing

Processing of many aspects of a problem simultaneously; the brains natural mode of info processing for many functions (e.g. vision); REMEMBER FORM, DEPTH, MOTION, COLOR → Furries Don’t Mind Cancer

Young-Helmholtz Trichromatic Theory

Retina contains 3 different color recptors/cones, with one most sensitive to red, green, or blue; when stimulated in combo, these receptors can produce perception of ANY color

Ewald Hering’s Opponent-Process Theory

There are 3 additional opposing retinal processes that enable color vision: red vs. green, blue vs. yellow, black vs. white; some cells are stimulated by green and inhibited by red, and vice versa; En route to the brain, neurons in the retina & thalamus code color-related info from the cones into pairs of opposite colors; explains afterimage

Gestalts

An organized whole; our tendency to integrate pieces of info to meaningful wholes

Gestalt psycholog(y)(ists)

Emphasize that we often perceive the whole of things, rather than its parts

Figure-ground

Organization of visual fields into objects that stand out from their surroundings

Grouping

Perceptual tendency to organize stimuli into coherent groups; include Proximity, Continuity, & Closure

Proximity

Our tendency to group nearby figures together

Continuity

Our tendency to group smooth continuous patterns together rather than discontinuous ones

Closure

Our tendency to want to fill in gaps to create a complete, whole object/image

Depth Perception

The ability to see objects in 3D, although images that strike our retinas are 2D; allow us to judge distance

Visual Cliff Experiment

Experiment that tested depth perception in infants & young animals; infant → placed on platform where the other half is hard, transparent glass; DEPTH PERCEPTION IS INNATE IN MANY OTHER ANIMALS, HOWEVER, DEPTH PERCEPTION SEEMS TO BE A LEARNED TRAIT IN HUMAN BABIES

Binocular Cues

Depth cues that depend on the use of 2 eyes

Retinal Disparity

A binocular cue for depth perception; compares the slightly different visual images from both retinas, so that the brain can compute distance and depth; the greater the difference between 2 images, the closer the object

Monocular Cues

Depth cues that are available to either eye alone

Interposition

Monocular cue; when one object blocks the view of another, we perceive it to be closer

Linear Perspective

Type of depth monocular cue that the human eye perceives when viewing 2 parallel lines that APPEAR to meet at a distance

Relative size

Type of monocular cue, where we perceive smaller objects as farther away

Relative motion

Type of monocular cue where objects seem to move when focused on a fixation point; objects beyond fixation point → appear to move w/ you; objects in front of point → appear to move backward; objects farther away from point, faster it’ll appear to move

Stroboscopic movement

Perception of continuous movement in a rapid series of slightly varying images; commonly seen in animation films & its many frames

Phi Phenomenon

Illusion of movement when 2 or more adjacent lights blink on & off in quick succession

Perceptual constancy

Perceiving objects as unchanging even as illumination & retinal images change

Color constancy

Perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object

Brightness constancy

Perceiving familiar objects as having constant brightness despite illumination change; depends on relative luminance

Relative luminance

The amount of light an object reflects relative to its surroundings

Shape constancy

Perceiving familiar objects as unchanging in shape, despite the retina receiving changing images

Size constancy

Perceiving familiar objects as unchanging in size, despite changing retinal images

Perceptual adaptation

In vision, the ability to adjust to artificially displaced or even inverted visual fields; think of glasses that shift subject’s world and their adjustment to life

Audition

The sense or act of hearing; highly adaptive

Sound waves

Bands of compressed & expanded air; ears detect these changes in air pressure & transduce them into neural impulses that the brain decodes as sound

Frequency

The number of complete wavelengths that pass a point in a given time; determines pitch

Pitch

A tone’s experienced highness or lowness; depends on frequency

Low pitch

Long wave, low frequency - sounds

High pitch

Short wave, high frequency - sounds

Outer ear

Channels sound waves through the auditory canal to the eardrum

Auditory canal

The passageway from the outer ear to the eardrum

Eardrum (tympanic membrane)

Tight membrane that vibrates when soundwaves hit it, where the middle ear & its ossicles pick it up

Middle ear

Chamber between the eardrum & cochlea; contains 3 tiny bones called the ossicles (hammer, anvil, stirrup) that concentrate vibrations from the eardrum & transmits it to the cochlea

Ossicles - Hammer, Anvil, & Stirrup

Bones in the middle ear that amplify the vibrations picked up from the eardrum, & relay them to the fluid-filled cochlea

Cochlea

Coiled, bony, snail-shaped, fluid-filled tube in the inner ear; sound waves travel through its fluid & trigger neural impulses

Inner ear

Innermost part of the ear; contains the cochlea, semicircular canals, vestibular sacs, and the basilar membrane (inside of the cochlea)

Basilar membrane

Membrane lined with tiny ear hair cells; bend the ear hair cells when rippled by pressure changes in the cochlear fluid

Ear hair cells

Cells that trigger impulses/neural messages that’re then sent through the auditory nerve to the brain

Auditory nerve

bundled axons that send neural messages to the auditory cortex via the thalamus; similar to the optic nerve

Sensorineural hearing loss (nerve deafness)

Hearing loss caused by damage to the cochlea’s ear hair cells, or to auditory nerves

Conduction hearing loss

Hearing loss caused by damage to the mechanical system in the ear that conducts sound waves to the cochlea

Cochlear implant

A device for converting sounds into electrical signals & stimulating the auditory nerve through electrodes threaded into the cochlea; can restore hearing for some people

Place theory

Theory that links the pitch we hear, with the place where the cochlea’s membrane is stimulated; only explains how we hear HIGH PITCH sounds