Final: Old chapter on development

Question 1

What are the 2 most common methods used to measure visual acuity in infants?

Answer 1

1. using behavior (preferential looking)
2. Electrical signals recorded from the scalp (visual evoked potential)

Question 2

How is acuity determined?

Answer 2

by noting the smallest letters, a person can accurately identify

Question 3

Stimuli are presented to the infant, and the experimenter watches the infant’s eyes to determine where the infant is looking. If the infant looks at one stimulus more than the other, the experimenter concludes that he or she can tell the difference between them.

Answer 3

Preferential looking technique

Question 4

Infants preferences to look at certain types of stimuli

Answer 4

Spontaneous looking preferences

Question 5

TRUE OR FALSE: infants choose to look at objects with contours over ones that are homogeneous

Answer 5

TRUE

Question 6

As we decrease the size of the bars, can the infants tell the difference between the grating and gray stimuli easier or harder?

Answer 6

Harder, the decrease in the size of the bars it becomes more difficult for infants to tell.

Question 7

How do we measure an infant’s acuity?

Answer 7

By determining the narrowest stripe width that results in looking more to one side

Question 8

Recorded by disk electrodes placed on the back of the infant’s head over the visual cortex; the pooled response of thousands of neurons that are near the electrode

Answer 8

Visual evoked potential (VEP)

Question 9

If the stripes or checks are large enough to be detected by the visual system, the visual cortex generates an electrical response; what is this electrical response called?

Answer 9

Visual evoked potential (VEP)

Question 10

What is the initial rapid improvement of acuity followed by?

Answer 10

a leveling-off period

Question 11

After 1 year of age, what is vision like?

Answer 11

Full adult acuity is reached

Question 12

Why do infants have low acuity at birth?

Answer 12

Their visual cortex is not fully developed

Question 13

What is the visual cortex like at birth?

Answer 13

It is only partially developed at birth and becomes more developed at 3 and 6 months, the time when significant improvements in visual acuity are occurring.

Question 14

How are the fovea cones different between infants and adults?

Answer 14

1. newborn’s cones have fat inner segments and very small outer segments, whereas the adult’s inner and outer segments are larger and are about the same diameter.
2. Infant’s fat inner segments create the coarse receptor lattice with large spaces between the outer segments. In contrast, the thin adult cones are closely packed, creating a fine lattice that is well suited to detecting fine details.

Question 15

What does the small size of infants’ outer segments mean?

Answer 15

The newborn’s cones contain less visual pigment and, therefore, do not absorb light as effectively as adult cones.

Question 16

What does it mean that the cone receptors’ outer segments effectively cover 68% of the adult fovea but only 2% of the newborn fovea?

Answer 16

means that most of the light entering the newborn’s fovea is lost in the spaces between the cones and is, therefore not useful for vision.

Question 17

a measure of the ability to see fine details

Answer 17

visual acuity

Question 18

Measured by determining the smallest difference between the dark and light bars of a grating at which an observer can still detect the bars.

Answer 18

Contrast sensitivity

Question 19

How can we determine how an infant perceives objects of different sizes?

Answer 19

measuring contrast sensitivity with a grating of different bar sizes

Question 20

a number of cycles of the grating per degree of visual angle

Answer 20

Spatial frequency of a grating

Question 21

Finer bars are generally associated with ____________?

Answer 21

higher spatial frequencies

Question 22

What does spatial frequency also depend on?

Answer 22

the grating’s distance from the observer

Question 23

measure of how fine the bar pattern is on the retina.

Answer 23

spatial frequency

Question 24

Used to determine the contrast sensitivity of gratings with different spatial frequencies, results in a plot of contrast sensitivity versus spatial frequency

Answer 24

Contrast sensitivity function (CSF)

Question 25

What does the contrast sensitivity function (CSF) indicate?

Answer 25

that adults are most sensitive to gratings with spatial frequencies drops off rapidly above 10 cycles per degree

Question 26

What do the curves for the 1 to 3 month-old infants indicate?

Answer 26

1. the infants’ ability to perceive contrast is restricted to low frequencies
2. even at these lower frequencies, the infants’ contrast sensitivity is lower than the adults by a factor of 20 to 100
3. infants can see little or nothing at frequencies above about 2 to 3 cycles/degree

Question 27

at 1 month after birth, what does their vision consist of?

Answer 27

infants can see no fine details and can see only relatively large objects with high contrast.

Question 28

at 3 month after birth, what does their vision consist of?

Answer 28

the infant’s contrast perception has improved so that the image looks clearly catlike

Question 29

What is our perception of color determined by?

Answer 29

the action of 3 different types of cone receptors

Question 30

When does color vision become present?

Answer 30

within the first 3 to 4 months of life

Question 31

one stimulus is presented to the infant repeatedly, and the infant repeatedly, and the infant’s looking time is measured on each presentation. As the infant becomes more familiar with the stimulus, he/she habituates to it.

Answer 31

Habituation

Question 32

An increase in looking time when the stimulus is changed

Answer 32

Dishabituation

Question 33

What does the occurrence of dishabituation mean?

Answer 33

that the second stimulus appears different to the infant from the habituation stimulus

Question 34

What did Bornstein conclude?

Answer 34

4-month-old infants categorize colors the same way adult trichromats do

Question 35

Which develops first: binocular disparity or pictorial depth cues?

Answer 35

binocular disparity

Question 36

What is one requirement for the operation of binocular disparity?

Answer 36

The eyes must be able to binocularly fixate so that the two foveas are directed to exactly the same place.

Question 37

Do infants have a precise ability to fixate binocularly?

Answer 37

Newborns only have a rudimentary, imprecise ability to fixate binocularly, especially on objects that are changing in depth

Question 38

The perception of depth due to binocular disparity

Answer 38

stereopsis

Question 39

What would happen if we presented a random-dot stereogram to an infant?

Answer 39

Since their visual system cannot yet use disparity info, all he/she sees is a random collection of dots

Question 40

When does the ability to use disparity info to perceive depth emerge?

Answer 40

sometime between 3 1/2 and 6 months of age.

Question 41

they depend on experience with the environment and the development of cognitive capabilities.

Answer 41

pictorial cues

Question 42

When do infants begin to use pictorial cues, like overlap, familiar size, relative size, shading, linear perspective, and texture gradients?

Answer 42

between about 5 and 7 months of age

Question 43

TRUE OR FALSE: young infants can recognize their mother’s face shortly after they are born

Answer 43

TRUE

Question 44

what percentage of time did newborns look at the mother?

Answer 44

63%

Question 45

an inability to recognize faces

Answer 45

prosopagnosia

Question 46

What helps babies recognize their mother?

Answer 46

their hairline: the high contrast border between the mother’s dark hairline and light forehead apparently provides important info about the mother’s psychical characteristics that the infant uses to recognize its mother.

Question 47

The ability to perceive a unitary object despite the fact that parts of it are out of sight or partly occluded

Answer 47

Object unity

Question 48

How do infants perceive objects as continuing behind an occluding object?

Answer 48

MOVEMENT