1
Q
Why focus on infancy?
A
- very rapid changes in the first 2 years of life
- changes in one area enable changes in other areas
- methods of studying infants are different than methods for studying older children that can communicate more clearly with adults
- sheds light on how nature and nurture shape development
2
Q
Can babies see from birth?
A
- from birth, babies visually scan environment and pause to look at stuff
- yes, they can see from birth
3
Q
What are methods in infant research?
A
- preferential looking paradigm
- habituation paradigm
4
Q
What is the preferential looking paradigm?
A
- assesses infants’ preference for one stimulus over another
- present the baby with 2 stimuli beside each other at the same time
- if the baby looks longer at one stimulus than the other, it means that they can distinguish between the two and have a preference for one over the other
- use eye tracking
5
Q
What do infants prefer to look at? (preferential looking paradigm)
A
- stimuli that are more complex
- more saturated in colour
- familiar, known
6
Q
What is the habituation paradigm?
A
- takes advantage of babies’ natural preference for novelty
- assesses infants’ ability to discriminate between stimuli
- 2 phases: habituation phase and test phase
7
Q
What is the habituation phase?
A
- repeatedly present infant with a stimulus until they habituate to it
- reduced or stopped response to a stimulus
- looks at it less
- wait for infant to get bored
8
Q
What is the test phase?
A
- present habituated, old, stimulus with a new stimulus
- dishabituation: if the baby shows greater interest in/looks longer at the new stimulus, they can tell the difference between the two
- if the baby looks at stimuli equally, they can’t tell the difference between stimuli
9
Q
What is visual acuity and how is it assessed?
A
- sharpness of visual discrimination
- assessed by using preferential looking paradigm
- Infants presented with a succession of paddles with increasingly narrower stripes and narrower gaps between them until infant can no longer distinguish between stripped paddle and plain gray one
10
Q
How is visual acuity at birth?
A
- at birth, infants have poor visual acuity
- prefer to look at patterns with high visual contrast
- don’t discriminate between stimuli with lower contrast sensitivities
- blurry, grayscale
11
Q
Why do infants have poor visual acuity at birth?
A
- due to immaturity of cone cells in infants’ retinas
- cone cells: light sensitive neurons involved in seeing fine details and colours
12
Q
When do infants obtain adult like visual acuity?
A
8 months
13
Q
What colours can infants see at birth?
A
- they see in grayscale
14
Q
When does colour vision appear?
A
- 2 months
- can see red first
15
Q
When do infants obtain adult like colour perception?
A
- 5 months
- due to maturity of cones and visual cortex
- can discriminate between colour categories and between hues of the same colour
16
Q
What is visual scanning like at birth?
A
- infants scan their visual environment and pause to look at something
- but trouble tracking moving stimuli because eye movements are jerky, eye muscles not fully developed
17
Q
What is visual scanning like at 4 months?
A
- able to smoothly track moving objects if moving slowly
18
Q
What is visual scanning like at 8 months?
A
- adult like visual scanning
- can smoothly follow objects
- improved visual scanning due to brain maturation
19
Q
Why is visual scanning important?
A
- because it’s one of the few ways that infants have control over what they observe and learn
- first form of autonomy
20
Q
What is face perception like at birth?
A
- newborns show a preference for faces or face-like stimuli vs. non-face-like stimuli
21
Q
Why are infants drawn to faces?
A
- fusiform face area
- infants have a general bias/preference for stimuli that are more top-heavy vs. bottom-heavy
22
Q
What is the fusiform face area?
A
- area in brain for recognizing and detecting faces
- special innate face perception mechanism?
23
Q
What is infants’ face perception in relation to their mother?
A
- infants very quickly learn to recognize and prefer their own mother’s face
- just a few days after birth, babies prefer their mother’s face compared to another woman’s face
24
Q
What is a face specialist?
A
- better at distinguishing between faces that are frequently experiences in their environment
- can distinguish between 2 human faces but struggle to distinguish between 2 monkey faces
25
When do infants become face specialists?
- 9 months
26
What is a face generalist?
- equally good at distinguishing human AND monkey faces
27
What is perceptual narrowing?
- tuning of perceptual mechanisms to the specific sensory inputs that infants encounter in their daily life
- improves perception of stimuli encountered often
- decline in the ability to distinguish stimuli that are not present in the infant's environment
- present for several perceptual domains
- result of synaptic pruning
28
What is synaptic pruning?
- elimination of synapses to increase the efficiency of neural communication
- use it or lose it principle
- neural connections being used are maintained while those not used are lost
29
What is synaptogenesis?
- formation of synapses between neurons
- rapid synaptogenesis right after brith
- results in hyper-connectivity in brain
- more connections than we need
- not efficient
30
What is the evidence of perceptual narrowing in face perception?
- infants becoming face specialists
- infants demonstrate the other race effect
31
What is the other race effect?
- people find it easier to distinguish between faces of individuals from their own racial group than between faces from other racial groups
- not innate
- the exposure effect
- during the first few months of life, 96% of faces that babies are exposed to are females from their own race
- if infant is equally exposed to faces of different races, will not show other race effect
32
When do infants demonstrate the other race effect?
- 9 months
- can only distinguish between faces of own race
33
How is face perception impacted in infants with autism spectrum disorders?
- people with ASD often have difficulty with face perception
- prefer to not look at eyes
- toddlers with ASD preferred looking at geometric shapes over pictures of people (opposite of typically developing kids)
- infants' preference for non-faces could be an early indicator that the infant will later be diagnosed with ASD
34
What is perceptual constancy?
- the perception of objects as being constant in size, shape, colour, etc in spite of physical differences in the retinal image of the object
35
Is perceptual constancy present from birth?
- yes, perceptual constancy is present from birth
- realized cube was same even when at different distances
36
What is object segregation?
- the ability to identify that objects are separate from each other
- separate by colour, shape, movement
37
Is object segregation present from birth?
- no, newborns do not have object segregation
- object segregation is not innate, has to be learned with experience
38
When do infants obtain object segregation?
- 4 months
39
What is binocular disparity?
- most important depth cue
- difference between the retinal image of an object in each eye that results in 2 slightly different signals being sent to the brain
- visual cortex combines the differing neural signals caused by binocular disparity
40
When can infants perceive depth (binocular depth cues)?
- 4 months
- depth perception relying on binocular disparity is present at 4 months
41
What is a sensitive period?
- a biological period during which certain kinds of experiences are necessary for an ability to develop normally
42
What is the sensitive period for binocular vision?
- from birth to 3 years
- depth perception from cue of binocular disparity is a natural result of brain maturation as long as the infant receives normal visual input from both eyes
- if infants do not receive normal binocular visual input until age 3, they may fail to develop normal binocular vision and have life-long difficulties with depth perception
43
When can infants perceive monocular depth cues?
- 6-7 months
44
What is the visual cliff?
- it assesses monocular depth cues
- 6 month old will not crawl over visual cliff but younger children will
- suggests that this aspect of depth perception needs to be developed through experience
45
What is the visual development timeline?
- at birth: rudimentary visual scanning, poor acuity, preference for high contrast, grayscale, preference for faces vs. non-faces, perceptual constancy
- 2 months: colour vision appears
- 4 months: object segregation and binocular depth perception appear
- 5 months: adult-like colour perception
- 6 months: face generalists, monocular depth perception appears
- 8 months: adult-like visual scanning and visual acuity
- 9 months: face specialists through perceptual narrowing
46
What visual abilities are innate?
- perceptual constancy
- preference for top-heavy stimuli
47
What visual abilities improve with brain maturation?
- visual acuity
- colour perception
- visual scanning
48
What visual abilities are experience dependent processes?
- object segregation
- face perception (perceptual narrowing)
- depth perception (sensitivity period)
