AP Psychology - Unit 3 (Sensation and Perception)

sensation

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

perception

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

bottom-up processing

analysis that beings 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

inattentional blindness

failing to notice a fully-visible, but unexpected object because attention was engaged on another task, event, or object

change blindness

a phenomenon of visual perception that occurs when a stimulus undergoes a change without this being noticed by its observer

absolute vs difference threshold

Absolute Threshold- the minimum amount of stimulus energy that a person can detect

Difference Threshold- the degree of difference that must exist between two stimuli before the difference is detected

signal detection theory

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

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 constant percentage (rather than a constant amount)

sensory adaptation

diminished sensitivity as a consequence of constant stimulation

prospagnosia

face blindness

transduction

conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, and smells, into neural impulses our brains can interpret

wavelength

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

hue

the dimension of color that is determined by the wavelength of light (blue, green, red, etc.)

intensity

the amount of energy in a light or sound wave, which as we perceive as brightness or loudness, as determined by the wave's amplitude

steps in vision

1. Light waves enter the cornea

2. Pass through the pupil

3. Pass through the lens

4. Projected onto the retina

5. Rods and cones transduce light waves into neural impulses

6. Neural impulses are sent to the optic nerve

7. Optic nerve carries messages from each eye to the primary visual cortex in the occipital lobe

rods vs. cones

retinal receptors:

rods --> detect black, white, and gray; peripheral and twilight vision, or when cones don't response

cones --> near the center of the retina, function in well-lit conditions, fine detail, color sensations

feature detectors

nerve cells in the brain that respond to the specific features of the stimulus, such as shape, angle or movement

parallel processing

the ability to take in multiple different forms of information at the same time - especially important in vision (seeing a bus coming towards you, you see its color, shape, depth, and motion all at once)

young-helmholtz trichromatic theory

the theory that the retina contains three different color receptors which, when stimulated in combination, can produce the perception of any color (red, blue, green)

opponent-process theory

the theory that opposing retinal processes in three systems (red-green, yellow-blue, white-black) enable color vision - helps explain color blindness

pitch

a tone's experienced highness or lowness - determined by the wavelength of sound

outer ear

the outermost part of the ear, consisting of the pinna and the external auditory canal

middle ear

the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window

inner ear

the innermost part of the ear, containing the cochlea with sensory receptor hair cells (hearing), and semicircular canals controlling vestibular sense (balance)

place theory

the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated

frequency theory

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

kinesthesis

the system for sensing the position and movement of individual body parts

gate-control theory

the spinal cord contains a neurological "gate" that blocks or allows pain signals to pass on to the brain

sensory interaction

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

gestalt

tendency to integrate pieces of information into meaningful wholes

figure-ground

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

binocular cues

depth cues that depend on the use of two eyes

retinal disparity

a binocular cue that compares images from the retinas in each eye and computing the distance depth can be perceived

monocular cues

depth cues available to either eye such as interposition (one object in front of another) and linear perspective (parallel lines appear to converge in the distance)

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 shapes, size, lightness, and color) even illumination and retinal images change

perceptual adaptation

in vision, the ability to adjust to an artificially displaced or even inverted visual field (using visual distortion goggles)

perceptual set

a mental predisposition to perceive one thing and not another - expectations have a big effect on how we 'see' the world

synesthesia

a perceptual phenomenon when stimulation of one sensory or cognitive pathway leads to involuntary experiences in a second pathway (hearing music, but seeing colors)