Mod 20-25 Terms

Selective Attention

the focusing of conscious awareness on a particular stimulus

Cocktail Party effect

ability to attend to one voice among a sea of other voices

Interposition

if one object partially blocks our view of another, we perceive it as closer

Relative height

we perceive objects higher in our field of vision as farther away.

Relative size

if we assume two objects are similar in size, most people perceive the one that casts the smaller retinal image as farther away

Relative motion

as we move, objects that are actually stable may appear to move

Linear perspective

Parallel lines appear to meet in the distance. The sharper the angle of convergence, the greater the perceived distance

Light and Shadow

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

What are the monocular depth cues?

relative height, relative size, interposition, relative motion, linear perspective, and light and shadow

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

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

Bottom-up Processing

analysis that begins with the sensory receptors and works up to the brains integration of sensory information (sensory receptors to a higher processing)

Top-down Processing

information processing guide by higher-level mental processes, as when we construct perceptions drawing on our experiences and expectations (experiences and expectations to perceptions from sensory input)

All our senses

• receive sensory input

• transform that stimulation into neural impulses

• deliver the neural information to our brain

transduction

conversion of one form of energy into another (transforming stimulus energies into neural impulses 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

absolute threshold

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

signal detection theory

a theory predicting how and when we detect the presence of a faint stimulus amid background stimulation

(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 (stimuli you cant consciously detect 50% of the time)

difference threshold

the minimum difference between two stimuli required for detection 50 percent of the time (a just noticeable difference)

Weber’s Law

the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (not a constant amount)

sensory adaptation

diminished sensitivity as a consequence of constant stimulation (this helps us focus on changes in the environment) (less aware because our nerve cells fire less often)

perceptual set

a mental predisposition (tendencies and assumptions) to perceive one thing and not another

concepts or schemas

organize and interpret unfamiliar information

perceptions are fed by three things

sensation, cognition, and emotion

(ESP) extrasensory perception

the controversial claim that perception can occur apart from sensory input (includes telepathy, clairvoyance, and precognition)

parapsychology

the study of paranormal phenomena (ex. ESP and psychokinesis)

wavelength

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

what determines hue

wavelength

hue

the dimension of color

Intensity

the amount of energy in a light wave or sound wave, that influences what we perceive as brightness or loudness

intensity is determined by

a waves amplitude

intensity influences

brightness

Cornea

the eyes clear, protective outer layer, covering the pupil and iris (where the light enters the eye) (bends light to help provide focus)

Pupil

the adjustable opening in the center of the eye through which light enter

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 (dilates and constricts due to light intensity)

Lens

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

retina

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

why doesnt the retina see a whole image?

receptor cells change light energy into impulses and forward them to the brain

Accommodation

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

What is nearsightedness caused by?

the lens focusing the image on a point in front of the retina

what are the two types of photoreceptors

rods and cones

rods

retinal receptions that detect black, white, and gray, and are sensitive to movement, necessary for peripheral and twilight vision, when cones dont respond (low color/detail sensitivity, periphery, high sensitivity in dim light)

cones

retinal receptors that are concentrated near the center of the retina and that function in daylight or in well-lit conditions, detect fine detail and color (high detail color sensitivity, center, low sensitivity in dim light)

bipolar cells

activates ganglion cells

how many cones and rods to a bipolar cell?

• one cone to a bipolar cell, several rods to a bipolar cell

optic nerve

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

blind spot

the pint 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

ganglion cells

axons twine together to form the optic nerve?

Where are rods located?

around the retina’s outer regions

What do retina’s neural layers do?

pass along electrical impulses and help encode and analyze sensory information

Young-Helmholtz trichromatic theory

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

opponent-process theory

the theory that opposing retinal processes enable color vision (ex. stimulated by green and inhibited by red)

color processing’s two stages

1. retina’s red, green, and blue cones respond to different color stimuli

2. cone’s responses are then processed by opponent-process cells

feature detectors

nerve cells in the brain’s visual cortex that respond to specific features of the stimulus, like shape, angle, or movement (receive information from individual ganglion cells and pass it to other cortical areas)

parallel processing

processing many aspects of a problem simultaneously; the brains natural mode of information processing for many functions

visual information processing

scene → retinal processing → feature detection → parallel processing → recognition

Gestalt

an organized whole, Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes

what is our first perceptual task

figure-ground

figure-ground

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

grouping

the perceptual tendency to organize stimuli into coherent groups

proximity grouping

group nearby figures

continuity grouping

smooth and continuous patterns not discontinuous ones

closure grouping

fill in gaps to create complete, whole object

depth perception

the ability to see objects in three dimensions although the images hitting the retina are 2-dimensional (allows us to judge distance) (partly innate, but also learned)

binocular cues

a depth cue, such as retinal disparity, that depends on the use of two eyes (use to judge the distance of nearby objects)

convergence

inward angles of the eyes focusing on a near object

retinal disparity

a binocular cue for perceiving depth (by comparing retinal images from the two eyes, the brain computes distance- the greater the disparity (difference) between the 2 images, the closer the object)

monocular cues

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

brain computes that motion is based on the assumption that

shrinking objects are retreating and enlarging objects are approaching

stroboscopic movement

slightly varying images seen as motion

phi phenomenon

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

perceptual adaption

the ability to adjust to changed sensory input, including an artificially displaced or even inverted visual field

Audition

the sense or act of hearing

height/amplitude determines

loudness

length/frequency determines

pitch

Frequency

the number of complete wavelengths that pass a point in a given time

Pitch

a tone’s experienced highness or lowness

long sound waves equal

low pitch and frequency (opposite is also true for short waves)

middle ear

the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrums 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 hearing loss (nerve deafness)

hearing loss resulting from damage to the cochlea’s receptor cells or to the auditory nerves (most common form of hearing loss) (cant be reversed)

Conduction hearing loss

hearing loss resulting from damage to the mechanical system that conducts sound waves to the cochlea (less common)

Cochlear implant

a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea (only way to restore hearing) (nerve deafness cant be reversed)

How does the brain interpret loudness?

the number of activated hair cells

Place Theory

theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated (explains how we hear high-pitched sounds but not low-pitched sounds)

Frequency Theory

theory that the rate of nerve impulses traveling up the auditory nerve matched the frequency of a tone, thus letting us sense its pitch (explains hearing low-pitches)

Volley Principle

neural cells firing in rapid succession, that creates a high frequency in waves per/sec

What makes a medium pitch?

a mix of the place and frequency theory

our sense of touch is a mix of what four things

pressure, warmth, cold, and pain

Nociceptors

sensory receptors that detect hurtful temps, pressures, or chemicals

Gate-control theory

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

When two times play a role in remembering pain

Peak pain and ending pain

Pain is a product of our

attention, expectations, and our culture

Biological influences on pain

activity in spinal cord’s large and small fibers, genetic differences in endorphin production, and the brain’s interpretation of CNS activity