Unit 3 - Sensation and Perception

Absolute Threshold

the minimum stimulus necessary to detect a stimulus correctly half of the time (going from nothing to something)

Accommodation

lens changes shape to focus near or far objects on the retina

Afterimages

explained by the opponent process theory of when we see a color afterimage after the initial stimulus is gone

Amplitude

correspond to our perception of loudness (volume); height of wave

Apparent Movement

perceiving a sense of motion (movement) where there isn't any actual movement happening

Binocular Depth Cues

rely on the use of both eyes to perceive depth

Blindsight

the ability to respond to visual information without consciously seeing it

Blindspot

created by the part of the retina where the optic nerve connects because there are no receptors in that area (we cannot see a certain area in our vision, but since we have two eyes, one eye compensates for the other)

Bottom-Up Processing

sensory receptors relay info to the brain to be interpreted

Change Blindness

failure to notice changes in the environment

Closure

grouping disconnected pieces into a meaningful whole

Color Blindness

when cones in the retina malfunction, making it difficult to distinguish between certain colors

Conductive Hearing Loss

problem transferring sound waves any where along the route through the outer or middle ear; hearing aids can help

Cones (blue, green, red)

enable color perception; most located in fovea, center of retina

Convergence

turning the eyes inward to focus on a nearby object creates muscular tension that the brain uses as a cue for depth perception

Cornea

the clear outer covering of the eye that offers it protection

Depth Perception - Visual Cliff

ability to see the world in three dimensions and know how far away an object is; develops in first six months of life

Dichromatism

when a person can't see a certain set of two colors (so they can only see one set)

Eardrum

a tight membrane that vibrates when sound waves hit it

Farsightedness

nearby objects are focused beyond the retina

Figure Ground

perceiving figures that stand out from the surrounding background

Fovea

the area that light is focused onto on the retina; center macula, acuity is the highest

Frequency

corresponds to our perception of pitch; length of sound wave

Frequency Theory

nerve impulses match the frequency of a tone, enabling us to sense its pitch; best for low pitch

Ganglion Cells

nerves that transmit visual messages

Gate Control Theory

states that the spinal cord has a “gate” that blocks/allows pain signals to pass into the brain; it is opened by the activity of pain signals travelling up the nerve fibers

Gestalt Psychology

based upon the idea that we experience things as unified wholes

Gustation

a chemical sense responsible for tasting

Hue

the color experienced

Inattentional Blindness

failure to see visual objects when attention is directed elsewhere

Inner Ear

sound waves are transduced into coded neural messages; semicircular canals, cochlea, auditory nerve

Intensity

determined by the wave’s amplitude

Interposition

objects that are obscured by other objects are perceived as being farther away

Just-Noticeable Difference (JND)

minimum change in a stimulus that can just barely be detected (going from something to something); difference threshold

Kinesthesis

feedback about positions and orientation of body parts in relation to each other; millions of position and motion sensors are located in the muscles, tendons, and joints

Lens

focuses light onto the retina

Linear Perespective

objects and the spaces between them look smaller as they becomes more distant; parallel lines appear to converge as they recede into the distance

Macula

light-sensitive tissue, back of the eye

Medium Tasters

average number of taste buds, typical flavor perception

Middle Ear

sound waves are amplified; ossicles

Monochromatism

a person can't see any color and only sees the world in black, white, and shades of gray due to the absence of cones

Monocular Depth Cues

can be perceived by only one eye

Nearsightedness

faraway objects are focused in front of the retina

Nociceptors

specialized nerve endings that detect pain, transmitting signals to the brain whenever something potentially harmful happens

Nontasters

fewer taste buds, less intense flavor perception

Olfactory Bulbs

chemically sensed floating odor molecules; gather the messages from the olfactory receptor cells, then sends this message straight to the brain (no thalamus)

Olfactory System

the sensory system responsible for our sense of smell

Opponent-Process Theory

there are three sets of color-sensitive ganglion cells: red-green, blue-yellow, black-white (light waves excite one color pair and inhibit the opposing color)

Ossicle Bones

three small bones in the middle ear that transmit sound waves or vibrations to the inner ear and help amplify sound

Pain

detected by nociceptors and processed by the brain

Parallel Processing

processes color movement, form, and depth simultaneously in different areas; integrates dimensions of visual info interpreted in different areas of the brain

Perceptual Set

perception influenced by expectations, preconceptions, culture, experiences (top-down processing); we create it for interpreting stimuli that confirms expectations; schema

Phantom Limb

when someone feels pain in a missing body part after it has been amputated; real pain and is the body adjusting to the change

Pheromones

molecules secreted by members of the same species; often serving as communication signals

Photoreceptors

specialized cells in the retina that convert light energy into electrical signals; cones and rods

Pitch

how high or low a stimulus sounds

Place Theory

sound frequencies stimulate basiliar membrane on specific hair cells (places) resulting in perceived pitch; explains how high pitch is detected

Prosopagnosia

a condition where you struggle to recognize faces or can't interpret facial expressions and cues; “face blindness”

Proximity

perceive objects as belonging together when they are close to one another

Pupillae

small bumps on the tongue containing around 200 taste buds each

Referred Pain

on the surface

Relative Clarity

nearby objects are clearer than more distant objects

Relative Size

an object that appears larger than another object believed to be of the same size is judged to be closer

Retina

light-sensitive inner surface of the eye containing a vast network of photoreceptors

Retinal Disparity

the difference in the images of objects projected onto the retina is used by the brain as a cue to gauge the distance of the objects; nearby objects produce more of this

Rods

detect black and white vision; function in dim light; necessary for peripheral vision and twilight vision

Selective Attention

the focusing of conscious awareness on a particular stimulus while tuning out the rest (Cocktail Party Effect)

Semicircular Canals

three interconnected tubes in the innermost part of the ear; primary structures involved in the vestibular system

Sensation

detection of environmental stimuli, such as sounds, objects, and smells

Sensorineural Hearing Loss

damage to the inner ear; can be caused by excessive loud sounds (earbuds, concerts, etc), implants can help

Sensory Adaptation

diminishing sensitivity to and unchanging stimulus; allows for freedom to focus on informative changes without uninformative background stimuli

Sensory Interaction

multiple sensory modalities combine to a single perception (smell and taste interact to create flavor)

Similarity

tendency to group objects that have similar characteristics

Somatic Pain

sharp, from the skin and muscles

Sound Localization

ears on either side of the head gives us stereophonic hearing

Supertasters

more taste buds, heightened sensitivity to flavors

Sweet

sugary and pleasurable flavor; energy (glucose)

Sour

tart and acidic; potentially toxic acid

Salty

salt taste; sodium essential for physiological processes

Bitter

bad and harsh; potential poisoning

Umami

meaty and savory; proteins to grow and repair tissue

Oleogustus

fatty and oily; warning to stop eating (perhaps moldy/unsafe) or satisfactory

Synesthesia

when one sense is simultaneously perceives as if by one or more additional senses; “joined perception”

Taste Receptors

pores located in taste buds that detect food chemicals, allowing us to experience different flavors

Thalamus

receives sensory and motor signals from the body and transmits them to the appropriate areas of the cerebral cortex; “relay center”

Thermoreceptors

sensory neurons that are sensitive to change in temperature

Timing Method

noting direction of sound by which ear is stimulated first (best with low-frequency sounds)

Top-Down Processing

previous experience and expectations affect the detection and analysis of information from the senses; explains visual illusions

Touch

pressure; sensed by many different cells under the skin that spread out and perceive constant pressure as force; we sense the placement by the place where the never endings fire

Transduction

the transforming of stimulus energies into neural impulses that the brain can deduct; “to transform”

Trichromatic Theory

three types of cones sensitive to different wavelengths (red light-long, green light-medium, blue light-short); colors other than red, green, and blue simulate a combination of cones

Vestibular Sense

how the body is oriented in space (balance)l semicircular canals are the primary structures involved

Visceral Pain

from organs

Visual/Optic Nerve

a bundle of nerve fibers that carries visual information from the retina to the brain

Volley Theory

groups of neurons work together to perceive sounds at frequencies beyond the individual firing; by firing rapidly, it creates a “volley” of signals

Volume Method (Hearing)

noting direction of sound by which ear is stimulated the most vigorously (best with high-frequency sounds)

Wavelength

distance from one peak to another

Weber’s Law

for a difference to be perceptible, two stimuli must differ by a constant proportion (1/30) rather than amount; as stimuli increase, the JND becomes proportionally larger