Lecture 2 - Visual Development Flashcards
Why is Infancy Important?
1) Very rapid changes occur within the first 2 years of life
2) Changes are catalysistic in nature
3) Methods used to study infants are only applicable during infancy (limited window to use exclusive methods)
4) Large source of information for nature VS nurture debate
What do Infants see?
Assumed that infants were blind, however they actually possess the ability to scan and fixate. It becomes difficult to measure what they see since they cannot self-report, so empirical (unconscious) methods are used.
Preferential Looking Paradigm
Assess preference for objects by showcasing them simultaneously and recording which the child stares at longer.
Results suggest 1) Infants can prefer things
2) Infants can distinguish between two different things
According to the Preferential Looking Paradigm, what type of stimuli do children prefer?
More complex, saturated + Familiar Objects.
Habituation Paradigm
Makes use of infants’ innate interest in novel stimuli. Infant is habituated to one object than shown it again alongside a new object. Successful habituation is seen through lessened/ceased interest in the original stimuli and favouring the novel one.
Name 1 way that Habituation and Preferential Looking Paradigm Overlap
They both measure the ability to distinguish between stimuli
With regards to the habituation paradigm, define Dishabituation
When the child prefers the new object over the original one
Give an example of when an infant would prefer novel stimuli and familiar stimuli
Familiar: In general, infants’ prefer familiar.
Novel: However, repeated exposure will lead to lack of interest and infants will then be more likely to prefer novel stimuli.
Define Visual Acuity and how it is assessed.
Sharpness (preciseness) of visual discrimination (telling things apart).
Measured with preferential Looking task; since it is known that infants’ prefer high contrast stimuli (due to poor visual acuity).
Why do Infants have poor visual acuity?
Immature cone cells (we are born not fully baked due to large head- narrow hips Trade-off).
Cone Cells
Light-sensitive neurons involved in colour and fine details,
What is significant about month 8 and visual development?
Infants have fully matured (adult-like) visual acuity.
Provide the Birth-2M-5M Colour Perception Evolution in Infants
Birth=Gray scale
2 Months= Colour Perception begins
5 Months= Adult-like Colour Perception
Quick progression is due to rapid maturation of cone Cells and visual cortex.
What is Visual Scanning and why is it important?
The ability to track and fixate objects in our environment.
First instance of independence in childhood (they choose what they look at).
Provide the Visual Scanning Timeline
Birth= Infants scan and pause
4 Months= Infants can follow slow-moving stimuli
8 Months= Adult-like Visual Scanning, smooth pursuit.
Relies on brain maturation (time gated).
What is unique about infants and face perception?
Infants prefer faces/face-like stimuli.
Due to innate face perception mechanism (FFA) + The fact that we prefer top heavy stimuli (even when scrambled).
Mom’s Face Bias
In the first few days after birth, babies show a bias for mother’s face over the face of a random woman.
Face Specialist VS Generalist
Specialist: Around 9 months of age, can differentiate between two human faces.
Generalist: Before 9 months, can differentiate between faces of two different species but not same, own species.
Perceptual Narrowing + Two perceptual domains in affects.
Tweaking perceptual mechanisms in order to better receive frequently encountered stimuli. Consequently, less frequently encountered stimuli is more poorly received. This process happens across hearing and vision.
Synaptic Pruning
Process responsible for perceptual Narrowing, wherein the brain eliminates neurons and synapses that are inactive in order to increase efficiency of the active ones.
What is the link between Perceptual Narrowing-Pruning-Face Specialists-Other Race Effect
Pruning gives rise to Perceptual Narrowing which is seen through Face Specialists + Other Race Effect.
Other Race Effect
Easier to distinguish between faces of your own race than other races. Not innate, but rather due to exposure, since 96% of the faces that infants’ see during their first year of life are of their own race. Moreover, infants equally exposed to faces of different races do not show this effect.
Synaptogenesis
The formation of synapses, which occurs most rapidly within first year of life, resulting in a very interconnected brain, which is inefficient but malleable.
What is unique about face perception and autism?
Infants with autism struggle with face perception since they avoid eye contact, moreover they prefer geometric shapes of face shapes. These two behaviours are early signs of autism.
