Sensation & Perception

Prosopagnosia—“face blindness”

a neurological condition in which a person has difficulty recognizing or distinguishing faces, even familiar ones, despite having normal vision and intelligence

Sensation

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

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 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

Selective attention

the focusing of conscious awareness on a particular stimulus while ignoring other stimuli

inattentional blindness

failing to see visible objects when our attention is directed elsewhere

change blindness

failing to notice changes in the environment

choice blindness

failing to notice a mismatch between a chosen option and outcome presented

Cocktail party effect

the ability to focus on one specific conversation or stimulus while filtering out many others, yet still detect personally important information

Transduction

conversion of one form of energy into another. In sensation, the transforming of physical energy, such as sights, sounds, and smells, into neural impulses the brain can interpret

Psychophysics (relates physical characteristics of stimuli to experience)

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

Thresholds—Absolute

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

difference thresholds

the minimum difference between two stimuli required for the detection 50% of the time. We experience the difference threshold as a just noticeable difference

Signal detection theory

a theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise); assumes there is no single absolute threshold and that detection depends partly on a person’s experience, expectations, motivation, and alertness

Subliminal

below one’s absolute threshold for conscious awareness

Priming

the activation, often unconsciously, of certain associations, thus predisposing one’s perception, memory, or response

Weber’s Law

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

Sensory adaptation

diminished sensitivity as a consequence of constant stimulation

habituation

decreasing responsiveness to a repeated stimulus over time as the brain learns to ignore it

Wavelength of light = hue (color)

the distance from the peak of one light wave or sound wave to the peak of the next. Electromagnetic wavelengths vary from the short gamma waves to long pulses of radio transmission

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.

Intensity or brightness = amplitude of light wave

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

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

the 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 changed 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

Fovea

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

Rods

retinal receptors that detect black, white, and gray, and are sensitive to movement. Rods are necessary for peripheral and twilight vision, when cones don’t respond

Cones

retinal receptors that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. COnes detect fine detail and give rise to color sensations

Bipolar cells

neurons in the retina that receive signals from rods and cones and transmit them to ganglion cells

Ganglion Cells

the neurons in the retina whose axons form the optic nerve and carry visual information 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

Optic nerve

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

Occipital Lobe

part of the brain at the back of the head that processes visual information

Accommodation—bending of lens to focus

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

Feature detectors in occipital lobe

specialized neurons that respond to specific features of a visual stimulus such as edges, lines, angles, or movement

Parallel processing of sight

processing multiple aspects of a stimulus or problem simultaneously

Young-Helmholtz, TRICHROMATIC THEORY

the theory that the retina contains three different types of color receptors, one most sensitive to red, one to green, one to blue, which when stimulated in combination, can produce the perception of any color

Herring, OPPONENT PROCESS THEORY

the theory that opposing retinal processes (red-green, blue-yellow, white-black) enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green

Audition

the sense or act of hearing

Sound waves

vibrations that travel through the air and can be heard

pitch

the toner’s experienced highness or lowness, depends on frequency

frequency & loudness

the number of complete wavelengths that pass a point in a given time (for example, per second)

amplitude

the height of a sound wave, which determines the loudness

Decibel

measure of sound

Outer ear

the visible part of the ear that collects sound waves and funnels them into the

auditory canal

the tube that carries sound waves from the outer ear to the eardrum

eardrum

a thin membrane that vibrates when sound waves hit it

middle ear- three bones (hammer, anvil, stirrup)

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

oval window

a membrane-covered opening that transfers vibrations from the middle ear to the cochlea

cochlea

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

basilar membrane

a structure inside the cochlea that vibrates in response to sound and helps distinguish different frequencies/pitches

Organ of Corti

the sensory organ inside the cochlea that contains hair cells and converts vibrations into neural signals

hair cells

specialized receptors in the cochlea that transform vibrations into electrical signals for the brain

auditory nerve

the nerve that carries sound information from the cochlea to the brain

temporal lobe

the part of the brain responsible for processing auditory information

Conductive hearing loss

hearing loss caused by damage or problems in the outer or middle ear that prevent sound from reaching the inner ear

sensorineural hearing loss

hearing loss caused by damage to the inner ear or the auditory nerve nerve

Cochlear implant

a device that converts sounds into electrical signals and directly stimulates the auditory nerve, allowing individuals with severe hearing loss to to perceive sound

Place theory of pitch

in hearing, the theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated

Frequency theory of pitch

in hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch

Skin detects

pressure, warm, cold, pain

Gate-control theory of pain

the theory that the spinal cord contains a neurological “gate” that blocks pain signals or allows them to pass on the brain. The “gate” is opened by activity of pain signals traveling up small nerve fibers, and is closed by activity in larger fibers or by information coming from the brain

Gustation

sense of taste

5 taste sensations on tongue

salt, sweet, sour, bitter, umami (savory meat taste), oleogustus (fats)

Papillae

small bumps on the tongue that contain taste buds

taste buds

sensory receptors within papillae that detects taste chemicals and send signals to the brain

Synesthesia mixing senses

a condition in which stimulation of one sense automatically triggers a perception in another sense (seeing colors when hearing music)

Smell and taste are closely connected

without smell most foods taste bland

Olfactory system

our sense of smell

Olfactory bulb

– in the brain –bypass the thalamus (located close to hippocampus)

Smell and memory enhancement

smells are strongly linked to memory because olfactory bulb is connected to limbic system, making scents triggers for memories

Kinesthesia

our movement sense; our system for sensing the position and movement of individual body parts

Vestibular Sense

our balance sense; our sense of body movement and position that enables our sense of balance

Pheromones

secreted by glands and can affect sexual attraction, identification, etc.

Sensory interaction

the principle that one sense can 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 judgements

Inattentional blindness

failing to see visible objects when our attention is directed elsewhere

Change blindness

failing to notice changes in the environment

Perceptual set

a mental predisposition to perceive one thing and not another

GESTALT

an organized whole. Emphasized our tendency to integrate pieces of information into meaningful wholes.

Figure-ground

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

Grouping

the perceptual tendency to organize stimuli into coherent groups

Proximity

we group nearby objects together

Similarity

we group objects that are similar in appearance (color, shape, size)

Continuity (good continuation)

we prefer smooth, continuous patterns rather than abrupt changes

Closure

we fill in gaps to create a complete, whole object

Simplicity (Prägnanz)

we organize images in the simplest, most stable, and coherent form possible

Depth Perception

the ability to see objects in 3-D although the images that strike the retina are 2-D, allows us to judge distance

Visual Cliff in children (6 mo.)

a laboratory device for testing depth prescription in infants and young adults

Binocular depth cues

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

retinal disparity

a binocular cue for perceiving by depth. By comparing retinal images from the two eyes, the brain computes distance, the greater the disparity (difference) between the two images, the closer the object

Monocular depth cues

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

Relative size

smaller objects are perceived as farther away

Relative height

objects higher in the visual field are perceived as farther away

Linear perspective

parallel lines appear to converge with distance

Relative motion (motion parallax)

as we move, closer objects appear to move faster than distant ones

Interposition

if one object blocks another, it is perceived as closer