Vision

Question 1

What is visual acuity?

Answer 1

The ability to see fine detail

Question 2

How can visual acuity be tested?

Answer 2

Snellen chart

Question 3

What does it mean to have 20/20 vision?

Answer 3

The smallest line of text the average person can read from 20 feet away

Question 4

How do we see?

Answer 4

Sensory receptors in eyes respond to wavelengths of visible light energy (part of electromagnetic spectrum we can see)

Question 5

What psychological dimension does wavelength refer to?

Answer 5

Colour

Question 6

What psychological dimension does amplitude refer to? Purity?

Answer 6

Brightness and saturation

Question 7

What happens when light reaches the eye?

Answer 7

It passes through the cornea (outer tissue), which bends the light wave and sends it through the pupil

Question 8

What is the iris?

Answer 8

Coloured part of the eye and a muscle that controls the size of the pupil

Question 9

What do muscles behind the iris do?

Answer 9

Control the shape of the lens to bend the light wave and focus it onto the retina

Question 10

What is the retina?

Answer 10

Light sensitive tissue lining the back of the eyeball

Question 11

What is accommodation?

Answer 11

The process by which the eye maintains a clear image on the retina

Question 12

What happens if someone is farsighted?

Answer 12

Light is focused behind retina

Question 13

What happens if someone is nearsighted?

Answer 13

Light is focused in front of retina

Question 14

What are photoreceptor cells?

Answer 14

Cells on the retina that contain light sensitive pigments that transduce light into neural impulses

Question 15

What do cone cells do?

Answer 15

Detect colour, operate under normal daylight conditions and allow us to focus on find details

Question 16

What do rod cells do?

Answer 16

Become active under low light conditions for night vision

Question 17

What is the fovea?

Answer 17

An area of the retina where vision is the clearest and there are no rods at all

Question 18

What are the three major cone types?

Answer 18

S: responds to short wavelengths (blue)
M: responds to medium wavelengths (green)
L: responds to long wavelengths (red)

Question 19

What is trichromatic colour representation?

Answer 19

The pattern of responding across the three types of cones provides a unique code for each colour

Question 20

What is colour deficiency?

Answer 20

Genetic disorder in which one cone type is missing

Question 21

What is the colour opponent system?

Answer 21

Pairs of visual neurons work in opposition and a neuron corresponding to one colour fires less in response to wavelengths corresponding to the opposite colour

Question 22

What’s the ventral stream?

Answer 22

Visual pathway that travels across the occipital lobe into the lower levels of the temporal lobes. Include brain areas that represent an object’s shape and identity.

Question 23

What’s the dorsal stream?

Answer 23

Visual pathway that travels up from the occipital lobe to the parietal lobes. Connects with areas that identify the location and motion of an object.

Question 24

What’s visual-form agnosia?

Answer 24

The inability to recognize objects by sight due to damage to the ventral stream. Can still guide movements by sight though.

Question 25

What’s optic ataxia?

Answer 25

Difficulty using vision to guide their reaching and grasping movements, but can still recognize objects.

Question 26

What’s inattentional blindness?

Answer 26

Failure to perceive objects that are not the focus of attention

Question 27

What’s change blindness?

Answer 27

People fail to detect changes to the visual details of a scene

Question 28

What are image based recognition theories?

Answer 28

Objects are stored in memory as a template (mental representation that can be directly compared to a viewed shape in the retinal image)

Question 29

What’s the problem with image based recognition theories?

Answer 29

Recognition time is not dependent on object orientation

Question 30

What are parts based recognition theories?

Answer 30

The brain deconstructs viewed objects into a collection of parts called geons. Objects are stored in memory as structural descriptions.

Question 31

What is the problem with parts based recognition theories?

Answer 31

Object recognition only at the level of categories (i.e. how do you distinguish your mother’s face from a stranger’s)

Question 32

What are monocular depth cues?

Answer 32

Aspects of a scene that yield information about depth when viewed with only one eye. Rely on the relationship between distance and size.

Question 33

What are examples of monocular depth cues?

Answer 33

1) Relative/familiar size: smaller objects look farther
2) Linear perspective: parallel lines appear to meet as they travel into the distance
3) Texture gradient: texture becomes less and less apparent the farther it goes into the distance
4) Interposition: when one object overlaps another, the object that is partially obscured is perceived as being farther away
5) Relative height to the image

Question 34

Ames room

Answer 34

The effect works by utilizing a distorted room to create the illusion of a dramatic disparity in size. While the room appears square-shaped from the viewers perspective, it is actually has a trapezoidal shape.

Question 35

What is binocular disparity?

Answer 35

Binocular depth cue. The difference in the retinal images of the two eyes that provides information about depth. Brain uses this information to perceive how far away objects are.