Task 2 Development: Wonder Baby

Question 1

Contrast sensitivity

Answer 1

can detect a pattern only when it is composed of highly contrasting elements

Question 2

What techniques test visual acuity?

Answer 2

preferential-looking technique and visual evoked potential technique (VEP)

Question 3

Preferential-looking technique

Answer 3

o Different visual stimuli are typically displayed on two side-by-side screens
o If an infant looks longer at one of the two stimuli, the researcher infer that the baby is able to discriminate between them and has a preference for one over the other
o When infants prefer to look at certain stimuli this is called spontaneous looking preferences
o Infants look longer at objects with contours over ones that are homogenous

Question 4

Why is infant’s visual acuity low?

Answer 4

cones are immature near the fovea and further apart than in adults, poorly developed visual system forces them to see with rod-dominated peripheral retina

Question 5

Habituation technique

Answer 5

procedure involves repeatedly presenting an infant with a given stimulus until the infant’s response to it habituates (declines)
o Novel stimulus is presented  if infant’s response increases, the researcher infers that the baby can discriminate between the old and new stimulus

Question 6

Visual Evoked Potential Technique

Answer 6

• Measure acuity through an objective electrical response
• Recorded by disk electrodes on the back of the infant’s head over the visual cortex
• Pooled response of thousands of neurons that are near the electrode

Question 7

When is the visual cortex fully developed?

Answer 7

6 months

Question 8

When do infants reach adult’s level of visual acuity?

Answer 8

6 months

Question 9

Contrast sensitivity

Answer 9

can detect a pattern only when it is composed of highly contrasting elements, infants cannot due to immature cones

Question 10

Spatial frequency

Answer 10

number of cycles of the grating per degree of visual angle, in which one cycle is one light bar and one dark bar

Question 11

Contrast sensitivity function

Answer 11

• Used to determine the contrast sensitivity of gratings with different spatial frequencies resulting in a plot of contrast sensitivity vs spatial frequency
• For adults: most sensitive to 3 cycles per degree; ability to see low spatial frequencies drops off rapidly above 10 cycles per degree
• For Infants:
  1. The ability to perceive contrast is restricted to low frequencies
  2. Even at these low frequencies the infant’s contrast sensitivity is much lower than the adult’s
  3. Infants can see little or nothing at frequencies above about 2-3 cycles/degree -> the frequencies adults are most sensitive to

Question 12

When does colour vision develop?

Answer 12

first 3-4 months

Question 13

How to test for colour vision development?

Answer 13

Habituation technique

• As the infant becomes more familiar with the stimulus (habituation) it looks less and less each trial
• By presenting a new stimulus one can tell if the infant is able to see a difference by having an increased focus on the new stimulus (dishabituation)
• If the infant can’t see a difference he or she will continue to habituate to the old stimulus
• Result: 4 month old infants categorize colors the same way adults do

Question 14

Optical expansion

-> when does it emerge?

Answer 14

visual image of an object increases in size as the object comes toward us, occluding more and more of the background (depth cue) – key: movement (kinetic cue)

-> 1 month

Question 15

Binocular disparity

Answer 15

difference between the retinal image of an object in each eye that results in two slightly different signals being sent to the brain
o Using disparity information to perceive depth
o The closer the object we are looking at, the greater the disparity between the two images
o Becomes functional early

Question 16

Binocular fixation

Answer 16

fovea’s directed to same place - 3 months

Question 17

Stereopsis

Answer 17

visual cortex computes the degree of disparity between the eyes’ differing neural signals and produces the perception of depth
o Emerges around 4 months

Question 18

Monocular depth cues

-> when do they emerge?

Answer 18

perception cues that can be perceived by 1 eye alone

-> 6-7 months

Question 19

Pictorial depth

Answer 19

information conveyed in a 2D image making it appear 3D, pictorial cues (shading, familiar size, overlap) - 5 to 7 months

Question 20

Random-dot stereograms

Answer 20

technique in which infant wears special glasses
o When sensitive to disparity, they should perceive a moving rectangle and should move their eyes to follow it
o Found that infants younger than three months didn’t follow rectangle
o Children are attracted to moving stimuli but during first months, they have difficulty tracking them
o Only children older than three months can perceive depth and pictorial cues can develop even later

Question 21

Familiar size

Answer 21

if infants were sensitive to familiar size, they would perceive object to be closer if they remembered from the familiarization period, that this shape was smaller than the other one

-> develops around 5 to 7 months

Question 22

Perceiving human faces vs animal faces

Answer 22

develops at 9 months, “scheme” of face is made

Question 23

When does perceiving object unity develop?

Answer 23

4-6 months

Question 24

Intermodal perception

Answer 24

combining info from 2 or more sensory systems

Question 25

Sticky fixation develops when and when does it go away

Answer 25

2 months, 4 months

Question 26

Describe the fovea cones of infants

Answer 26

fat inner segments, large outer segments which leads to less visual pigment and thereby less efficient light absorption; the fat inner segments lead to bg spaces between outer segments where most of the light entering the fovea gets lost

Question 27

Operant conditioning

Answer 27

method in which infants are given headphones and either hear mother’s or stranger’s voice depending on length of breaks during sucking *found that 2 month-olds modify

Question 28

Name 2 monocular depth cues

Answer 28

1. linear perspective

2. relative size

Question 29

Relative size

Answer 29

monocular depth cue, when 2 or more things of a similar size appear smaller or larger depending on how far away they are

Question 30

Linear perspective

Answer 30

monocular depth cue, when parallel lines appear to converge in the distance at vanishing point

Question 31

Monocular depth cues include what category of depth cues?

Answer 31

pictorial depth cues (shading, size, familiar size, overlap)

Question 32

Social referencing

Answer 32

the process of communication whereby people actively seek and use others’ perceptions and interpretations of ambiguous situations to form their own interepretations of those situations

Question 33

when the the visual cliff is a dangerous situation infants use ___ only cues to modify their actions, whereas in non-threatening situations, infants additionally require ___ cues

Answer 33

face, vocal

Question 34

Which led to lowest crossing times?

• > face only
• > voice only
• > face and voice

Answer 34

face and voice

Question 35

Which is the most potent channel of emotional communication for infants?

• > voice
• > face

Answer 35

voice

Question 36

Infants only use facial cues in what kind of situations?

Answer 36

threatening situations