Chapter 6

Question 1

• is sometimes defined as waves of electromagnetic
energy that are between 380 and 760 nanometers (billionths
of a meter) in length

Answer 1

LIGHT

Question 2

plays an important role in the perception of
color

Answer 2

WAVELENGTH

Question 3

because it plays an important role in the
perception of brightness.

Answer 3

INTENSITY

Question 4

regulates the amount of light
reached by the retinas and which
give our eyes their characteristic
color

Answer 4

IRIS

Question 5

adjusts in response to
changes in illumination represents a
compromise between sensitivity
(the ability to detect the presence of
dimly lit objects) and acuity (the
ability to see the details of objects).

Answer 5

PUPIL

Question 6

• focuses incoming light
  on the retina.
  • The process of adjusting the
  configuration of the lenses to
  bring images into focus on the
  retina is called
  accommodation.

Answer 6

LENS

Question 7

• is the sensory
membrane that lies in the inner
surface of the back of the eyeball
• It is composed of several layers,
including one that contains
specialized cells called
photoreceptors.

Answer 7

Retina

Question 8

are the primary cell type in the
innermost cellular layer of the
retina, responsible for carrying
visual information from the eye to
the brain

Answer 8

Retinal Ganglion Cells(RGCs)

Question 9

are responsible for
complex processing of the retinal
image, specifically adjusting image
brightness and, by integrating
sequential activation of neurons,
detecting motion

Answer 9

Amacrine Cells

Question 10

are the central
neurons of the retina which carry
light-elicited signals from
photoreceptors and horizontal
cells (HCs) in the outer retina to
amacrine cells (ACs) and ganglion
cells (GCs) in the inner retina.

Answer 10

Bipolar Cells

Question 11

second-order
neurons in the vertebrate retina,
receiving direct excitatory input from
cone and rod photoreceptors.

Answer 11

Horizontal Cells

Question 12

• takes light focused by the cornea
and lens and convert it into
chemical and nervous signals
which are transported to visual
centers in the brain by way of the
optic nerve.

Answer 12

Photoreceptors

Question 13

• An indentation, about 0.33
centimeter in diameter, at the
center of the retina; it is the area
of the retina that is specialized for
high-acuity vision (for seeing fine
details).
• The thinning of the retinal
ganglion cell layer at the fovea
reduces the distortion of incoming
light.

Answer 13

Fovea

Question 14

• Created by the inside-out
structure of the retina, requires a
more creative solution

Answer 14

Blind Spot

Question 15

• the theory that cones and rods
mediate different kinds of vision.

Answer 15

Duplexity Theory

Question 16

• the process by which we perceive surfaces; the visual system
extracts information about edges and from it infers the
appearance of large surfaces).

Answer 16

Surface Interpolation

Question 17

(cone-mediated)
predominates in good lighting and
provides high-acuity (finely detailed)
colored perceptions of the world

Answer 17

Photopic vision

Question 18

(rod-mediated) In
dim illumination, there is not
enough light

Answer 18

Scotopic vision

Question 19

• graph of the relative
brightness of lights of
the same intensity
presented at different
wavelengths

Answer 19

Spectral
Sensitivity

Question 20

• One evening, just before dusk, while Purkinje was
walking in his garden, he noticed how bright most
of his yellow and red flowers appeared in relation
to his blue ones. What amazed him was that when
viewed at night, appeared completely in shades of
gray, but most of the blue flowers appeared as
brighter grays than did the yellow and red ones.
• It is the tendency for the peak luminance sensitivity
of the eye to shift toward the blue end of the color
spectrum at low illumination levels as part of dark
adaptation.

Answer 20

Purkinje effect

Question 21

• conversion of one form of energy to another

Answer 21

Transduction

Question 22

is the conversion of light to neural signals by
the visual receptors.

Answer 22

• Visual transduction

Question 23

• pigment-containing sensory
protein that converts light into
an electrical signal.
• it is required for vision in dim
light and is located within the
tightly packed disks that make
up the outer segment of the
retina’s photoreceptive rod cells,
which are specially adapted for
vision under low-light conditions.

Answer 23

Rhodopsin

Question 24

The the correct term for
colors such as blue,
green, and yellow

Answer 24

Hues

Question 25

The perception of object an object’s color
depends on the _____of the light.

Answer 25

wave lengths

Question 26

Proposed by Thomas Young in (1802), and refined by
Hermann von Helmholtz in (1852)

Their theory that any color of the visible spectrum can be
matched by a mixing together of three different wavelengths of
light in different proportions. -

Answer 26

Component Theory

Question 27

• Proposed by Ewald Hering in
(1878)
• There are two different
classes of cells in the visual
system for encoding color
and another class for
encoding brightness.

Answer 27

Opponent
Processing

Question 28

are pairs of colors
(e.g., green light and red light) that produce
white or gray when combined in equal
measure

Answer 28

Complementary colors

Question 29

Refers to the fact that the perceived
color of an object is not a simple
function of the wavelengths reflected
by it.

is the tendency for an
object to stay the same color despite
major changes in the wavelengths of
light that it reflects.

Answer 29

Color Constancy

Question 30

• the color of an object is determined by its
reflectance the proportion of light of different
wavelengths that a surface reflects

Answer 30

Retinex Theory

Question 31

• It is a failure of
recognition (gnosis
means to know ) that is
not attributable to a
sensory deficit or to
verbal or intellectual
impairment;

Answer 31

AGNOSIA

Question 32

• A specific agnosia for visual
stimuli. Visual agnosics can
see visual stimuli, but they
don’t know what they are.
• Movement agnosia
• Object agnosia
• Coloragnosia a

Answer 32

VISUAL
AGNOSIA

Question 33

• can usually
recognize a face as a face, but
they have problems recognizing
whose face it is.
• They often report seeing a
jumble of individual facial parts
(e.g., eyes, nose, chin, cheeks)
that for some reason are never
fused, or bound, into an easy-torecognize whole.
• In extreme cases,
prosopagnosics cannot
recognize themselves

Answer 33

PROSOPAGNOSIA

Question 34

• is a deficiency in the ability to see movement progress in
a normal smooth fashion.
•It can be triggered by high doses of certain antidepressants
•It is often associated with damage to the middle temporal (MT) area
of the cortex

Answer 34

Akinetopsia