AP Psych Unit 1 - Sensation (module 1.6)

sensation

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

sensory receptors

sensory nerve endings that respond to stimuli.

perception

the process by which our brain organizes and interprets sensory information, enabling us to recognize objects and events as meaningful.

bottom-up processing

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

top-down processing

information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations.

sensory transduction

the transforming of physical energy, such as sights, sounds, and smells, into neural impulses the brain can interpret.

psychophysics

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

absolute threshold

the minimum stimulus energy needed to detect a particular stimulus 50 percent of the time.

signal detection theory

a model that explains how people decide if a faint stimulus is present or just background noise under conditions of uncertainty.

subliminal

below one’s absolute threshold for conscious awareness.

difference threshold

the minimum difference between two stimuli required for detection 50 percent of the time.

weber’s law (weber-fechner)

the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount).

sensory adaptation

when you are exposed to a constant, unchanging stimulus over time, your sensory receptors become less responsive to it.

wavelength

the distance from the peak of one light or sound wave to the peak of the next.

intensity

the amount of energy in a light wave or sound wave, which influences what we perceive as brightness or loudness; determined by the wave’s amplitude (height).

hue

the dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth.

cornea

the eye’s clear, protective outer layer, covering the pupil and iris.

pupil

the adjustable opening in the center of the eye through which light enters.

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.

lens

the transparent structure behind the pupil that changes shape to help focus images on the retina.

retina

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

accommodation

the process by which the eye’s lens changes shape to focus images of near or far objects on the retina.

rods

retinal receptors located in the periphery and detect shape, movement and low light.

cones

retinal receptors located in center of the retina called the fovea and detect color and detail; sensitive to short, medium, and long wavelengths.

optic nerve

the nerve that carries neural impulses from the eye to the brain.

blind spot

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

fovea

the central focal point in the retina, around which the eye’s cones cluster.

young-helmholtz theory (trichromatic theory)

states that the human retina contains three distinct types of color receptors (cones) that are each sensitive to a different wavelength of light: short (blue), medium (green), and long (red); brain interprets yellow when both red and green sensitive cones are activated together.

opponent-process theory

states that color vision is controlled by three opposing pairs of receptor systems: red vs. green, blue vs. yellow, and black vs. white; focuses on explaining how color is processed after the cones.

feature detectors

nerve cells in the brain’s visual cortex that respond to specific features of the stimulus, such as shape, angle, or movement.

parallel processing

processing multiple aspects of a stimulus or problem simultaneously.

auditory sensory system

processes how we hear and understand sounds within the environment.

frequency

refers to how fast the wave vibrates and determines the pitch, how low or high a sound is.

pitch

a tone’s experience of highness or lowness.

middle ear

the chamber between the eardrum and cochlea containing three tiny bones that concentrate the vibrations of the eardrum on the cochlea’s oval window.

cochlea

a coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses.

inner ear

the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs.

sensorineural deafness

occurs when there is damage to the inner ear or auditory nerve.

conduction deafness

occurs when theres damage to the outer ear or middle ear, preventing sound from being properly sent to the inner ear.

cochlear implant

a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea.

place theory (place coding)

suggests that different pitches stimulate different places on the basilar membrane in the cochlea, this theory helps explain our ability to hear high-pitched sounds.

frequency theory (temporal coding)

suggests that the auditory nerves impulses correspond directly to the frequency of the sound wave; essentially the rate at which neurons fire match the frequency of the sound wave.

gate-control theory

suggests that the spinal cord contains a neurological “gate” that can either block pain signals or allow them to pass through to the brain.

gustation (taste)

the sense of taste, and types of tastes include sweet, sour, salty, bitter, umami, and oleogustus.

olfactory stimuli (smell)

stimuli relating to the sense of smell transduced and processed by structures in the nose and brain.

kinesthesis

your sense of body position and movement, this is your ability to know where your limbs are, even without looking.

vestibular sense

helps maintain balance and spatial orientation, essentially this is what allows you to stay upright.

sensory interaction

the principle that one sense may influence another, as when the smell of food influences its taste.

embodied cognition

the influence of bodily sensations, gestures, and other states on cognitive preferences and judgments.

priming

psychological phenomenon where exposure to one stimulus unconsciously influences how you respond to a subsequent stimulus.

semicircular canals

three interconnected fluid-filled tubes in the inner ear that sense head rotation and help the body maintain balance and stable vision.

phantom limb sensation

when people who have lost limbs report sensation or pain where the limb used to be.

just-noticeable difference (difference threshold)

the smallest difference between two stimuli that a person can detect at least 50% of the time.

synesthesia

neurological condition where one sense is experienced through another.

myopia (nearsightedness)

when the point of focus is in front of the retina, making distant objects appear blurry.

hyperopia (farsightedness)

when the lens focuses on light behind the retina, close objects end up looking blurry.

afterimages

the lingering visual illusion in which retinal impressions continue to exist after the removal of a color stimulus, this is the result of certain ganglion cells in the retina being activated while others are not. shows the opposite (complementary) colors and inverted brightness of what you originally stared at.

dichromatism

Color Vision Deficiency which occurs when someone is missing one type of cone, resulting in the individual to become confused between certain colors.

monochromatism

Color Vision Deficiency in which all cone cells are either missing or not working properly, resulting in the individual to see everything in different shades of one color, usually black, white, and grey.

prosopagnosia (face blindness)

a disorder characterized by the inability to recognize the faces of familiar people.

amplitude

refers to the height of the wave and determines the loudness or intensity of a sound.

selective attention

focusing conscious awareness on a particular stimulus.

inattentional blindness

failing to see visible objects when our attention is directed elsewhere.

change blindness

failing to notice changes in the environment; a form of inattentional blindness.

volley theory

suggests that groups of neurons take turns firing in succession to match the frequency of sound, which helps explain mid-range frequencies.

supertasters

individuals who have a higher than average number of taste receptors, allowing them to taste more intensely.

perceptual set

a mental predisposition to perceive one thing and not another.

figure-ground perception

brain's natural ability to separate a main object (the figure) from its surrounding background (the ground).

depth perception

the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance.

visual cliff

a laboratory device for testing depth perception in infants and young animals.

binocular cue

a depth cue, such as retinal disparity, that depends on the use of two eyes.

retinal disparity (binocular disparity)

the difference between the visual images projected onto the left and right retinas because the eyes sit a few centimeters apart on the face.

monocular cue

a depth cue, such as interposition or linear perspective, available to either eye alone.

phi phenomenon

an illusion of movement created when two or more adjacent lights blink on and off in quick succession.

perceptual constancy

perceiving objects as unchanging (having consistent color, brightness, shape, and size) even as illumination and retinal images change.

color constancy

the brain's ability to perceive the familiar color of an object as consistent and unchanging, even when the actual lighting and the wavelengths of light reflecting off it shift.

perceptual adaptation

sweet

energy source; triggered by sugars and carbohydrates.

salty

sodium essential to physiological processes: its taste is often described as salty and flavorful.

sour

potentially toxic acid; its taste is often described as tart, acidic, and tangy.

bitter

potential poisons; its taste is often described as sharp, strong, and unpleasant.

umami

proteins to grow and repair tissue, its taste is often described as the meaty, savory deliciousness that deepens flavor.

oleogustus

fats for energy, insulation, and cell growth; the unique taste sensation that is attributed to the perception of fats or lipids in food.

sound localization

the ability to identify the position any changes in the position of sound sources. is a complex process that involves the auditory system and several auditory cues to determine the direction and distance of sounds.

blindsight

a disorder in which people respond to visual stimuli without consciously perceiving them.

color vision deficiency

deficiency that occurs when one or more types of cone cells, or the ganglion cells that process color signals, do not function properly.

ganglion cells

the axons that meet at the back of the eye to form the optic nerve.

habituation

when you are repeatedly exposed to a stimulus and start to have a reduced response to the stimulus. often confused with sensory adaptation.

cross-sensory experience

where one sense is automatically triggered by another.

blue cones

interpret short wavelengths.

green cones

interpret medium wavelengths.

red cones

interpret long wavelengths.

red-green color blindness

most common type of dichromatism where an individual has difficulty distinguishing between different red and green hues.

pheromones

chemical signals released by an individual that affect the behavior or physiology of other individuals; detected by the olfactory system.

medium tasters

individuals with an average numbers of taste receptors, who have a more balanced sensitivity to different tastes.

nontasters

individuals that have fewer taste receptors, making them less sensitive to certain tastes.

nociceptors

located in the dermis; what helps detect harmful stimuli.