Cognitive Psych Exam 1

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

Transduction

the transforming of stimulus energies into neural impulses our brains can interpret.

absolute threshold

the minimum stimulation 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 (signal) amid background stimulation (noise).

difference threshold

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

method of limits

the difference between two stimuli is varied incrementally until the participant responds differently.

method of constant stimuli

a number of stimuli with different intensities are presented repeatedly in a random order.

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)

Wavelength

Horizontal distance between the crests or between the troughs of two adjacent waves

Cornea

outer covering of the eye, barrier

Iris

a ring of muscle tissue -controls the size of the pupil opening

pupil

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

lens

behind the pupil -changes shape to help focus images on the retina

Retina

the light-sensitive inner surface of the eye, has rods cones and muscle layers

Fovea

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

blind spot

the point at which the optic nerve leaves the eye

optic nerve

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

Rods

retinal receptors that tonesy; necessary for peripheral and twilight vision, when cones don't respond. Good at movement.

Cones

near the center of the retina and that function in daylight. Fine detail and color.

Parafovea

the area surrounding the fovea, where vision is less acute

Yarbus (1967)

tracked eyes with a suction cup when looking at a painting

bottom-up processing

analysis that begins with the sensory receptors and works up to the brain's integration of sensory information

top-down processing

information processing s drawing on our experience and expectations

dorsal stream

visual path in the parietal cortex that helps the motor system locate objects; the "where" path

ventral stream

what pathway in the temporal lobe - object identification

Patient DF (Miller and Goodale)

Temporal damage; had trouble matching orientation of card slot, but no trouble putting card through a slot ("what" pathway affected, "where" pathway fine)

simultaneous brightness contrast

lighter color appears brighter when surrounded by a darker stimulus than when surrounded by a lighter stimulus

lightness constancy

we perceive an object as having a constant lightness even while its illumination varies

color constancy

perceiving familiar objects as having consistent color

proximity

Things that are near each other we see as going together

similarity

Things that look alike go together - ex. Similarly colored dots

common region

Adding markings for groups makes a region where things go together

synchony

When things happen at the same time, that makes a group, ex. lights

continuation

The way we can follow a line when they overlap

Pragnanz

Visual system prefers regular shapes - ex. seeing circles instead of non-basic shapes

Closure

Preference for intact objects, and we form them even if there's negative space

trichromatic theory

Colors are sensed by combining the three types of light, red blue and green - cones

opponent-process theory

ganglion cells - Colors are perceived in terms of paired opposites ex. red (+) green (-) cells

substantive color mixing

ex. paint absorbs everything but it's actual color

additive

ex. phone light - sending color out

red + green

yellow light

red + blue + green

white light

convergence

binocular cue - the eyes converge inward when looking at an object

binocular disparity

the difference in the retinal images of the two eyes that provides information about depth

relative size

the smaller retinal image is farther away

texture gradient

Things that are nearby are individuals, things far away become a mass

light and shadow

Visual system has expectations as to where light is coming from - above

object

an edge with a surface in between

Hubel and Wiesel experiment

experiment w/ cat & rotating rod; diff neurons in brain fire depending on diff angles

hypercolumns

units of the visual cortex that process information from both eyes and contain angle, color, & location cells, contributing to depth perception.

recognition by components theory

a specific view of an object can be represented as an arrangement of simple 3-D shapes called geons

Bouba-Kiki Effect

tendency to name round shape bouba and jagged shape kiki

ambiguous figures

ex. duck rabbit - BU is what we see first, but once we know the second, we can force it w TD

Sperry

asked split brain patients to identify a word per eye - left hemisphere said right word, right side indicated left word

binocular dispa

convergence