Lecture 6 - Perceptual Knowledge & Action In Infancy Flashcards
Perceptual development
What are perceptual skills?
- vision
- touch (Proprioception, vestibular)
- audition
- smell, taste
Explorations by an infant
Even at a young age human infants need to be ab,e to perceive basic information from their environment
The groundwork for all future development
- visual analysis
- depth
- size
- angles
- constancies
- motion
- audition (instruction)
Newborns are quite passive
- if a bright light comes on, they attend to it
- scanning movements seem ‘inborn’
- reflexive responding to stimulation
With age, infants become more active
- purposefully seeking sensory information around them
- movement is an important contributor
- intentional interaction with environment
Combining information
Inter-sensory integration: infants begin to integrate information from sevral senses (in thr same way adults do)
- e.g. watching an adult do actions whilst listening to a nursery rhyme (auditory and visual combination)
Cross-modal transfer: infants can percieve something via one modality and transfer the information to mother modality e.g. Meltzoff and Borton (1979)
- infants approx 29 days old
- 2 dummies, one smooth the other bumpy. Visually presented with both dummies
- 71% looked longer bat yummy they were sucking
Learning inter-sensory integration and cross-modal transfer are essential for successful development
Think later in module about cognitive skills such as language
Researcher challenges?
Linguistic abilities
Concentration/attention
Crying
Sleeping
Ethical and consensual access
We need to overcome these challenges to be able to learn more about infant abilities
Auditory perception
Babies can hear before birth - from 26b weeks gestation snd are likely learning their mother’s voice pre-brith and show a presence for after birth
Basic auditory capabilities are relatively mature at brith and they can discriminate some speech sounds, even from other languages
At around 7-9 months, begin to focus on individual sounds plus rhythm (language development)
Obver the first year of like the greatest change in hearing is the ability or organise sounds into complex patterns
-methods-
Non-nutritive sucking (NNS)
- Nazzi et al (1998) infant sucking rate indicated the ability to discriminate bewteen ‘pitch contours’
Brain responses (e.g. ERP)
- Winkler et al (2003) similar to adults, newborn infants segregate concurrent streams of sound,allowing them to organise auditory input
Precursor of language
Even the foetus can learn about the irregularities of language from the furled language they hear inside the womb
Infants aged 2-7 months listen longer to real speech sounds than to muddles up rhythms
NNS indicated taht infants can disctimate between their native language and a foreign language
- they suck more for their native language
Year 1 is all about the structure and organisation of sound
Language discrimination
Werker & Tees (1984)
Tested English learning infants between 6-12 months at discriminating non-native speech contacts (Hindi and Salish)
% of English learning infants at 3 ages reaching criterion in test of discrimination of Hindi and Salish. A small number of Hindi and Salish learning infants were also tested at 11-12 moths as a control
Vision
Move on to think about development of visual percpetion
We will consider some of the main methods used by researchers when we investigate the development of visual perception
Perhaps, the most important of our senses
Most actively extends our reach beyond’s our bodies and supports exploration of the environment
Development is supported by the rapid development of the visual cortex
- 2 months - discriminate colours
- 3 months - discriminate objects
- 6 months - visual acuity 20/100
- develop accuracy in tracking
Visual acuity
The ability to see fine-grained detail
- method-> preferential looking-
Based on infants’ spontaneous looking preference
Not asking the infant to specifically looking in one direction
Seeing where their preferences lie in order to learn about their abilities, preferences, discriminations
Done by eyetacking during a task, done by holding a baby to look at a stimulus and using a camera to track their eye movements
- these have dveloped over the years and are now much more readily available
If the infant can tell the difference between the images, they will look longer at a striped circle than a solid circle
- this shows an innate preference for patterned images
As lines on the stripes get closer and the image becomes more fine grained the infant can’t tell the difference and will attend equally at both circles
- this is an assessment of visual acuity
Visual acuity is the ability to see fine detail
Poor at birth
- under developed visual cortex
When does it improve?
- rapid development in the first 6 months to just below adult level
- followed by a leveling off period
- full acuity not developed until after 1 year
Contrasts and change in colour n vision
Infants are only sensitive to a small fraction of the pattern information available to adults
At 1 month can see no fine details (visual acuity)
Can only see large items with high contrast
Slightly worse than adult night vision
Explains the reason why innate prefer to look at images with high contrast
Also have an increase in colour vision - by 6 months old their colour vision is much more dveloped but still not fully there
Preference for edges
Eye scanning shows that even from a month old, infants have a preference for faces
Eye scanning results from images of faces:
- 1 month olds scan perimeters of shapes
- two month olds scan both the perimeters and the interiors of shapes
Importance of faces
“Faces are probably the most important visual stimulus to us as humans, certainly in terms of our social interactions” (Taylor, Batty & Itier, 2004)
- the human ability to recognise faces is remarkable
- a special biological and social value
- socially important cues
-seeing faces in everything-
Pareidolia = a psychological phenomenon involving a stimulus (an image or sound) that the mind perceives a familiar pattern where none actually exists
E.g. man in the mood cloud faces
-development of face processing-
Face processing follows a prolonged developmental course before becoming adult-like
-face processing hypotheses-
Morton & Johnson, 1991
Structural hypothesis:
- the neonate brain contains innate information concerning the structure of faces
- CONSPEC
- a visual perceptual ‘device’ available at brith with no prior experience necessary
Sensory hypothesis:
- classes of stimuli are preferred as a result of their general properties
- CONLERN
- the ability to learn about a human face, as a consequence of directing attention to faces - experience is required
Early preference for faces?
Neonates and infants selectively prefer schematic faces over scrambles faces and blank faces
Face perception - Nature vs nurture
Imitation of facial expression
- innate ability to imitate facial expressions -“act of social cognition”
- evidence for CONSPEC
Innate preference for attractive faces
- newborns less than 3 days old show this preference across age, gender and ethnicity
- the “attractiveness effect” is a robust finding
- however, an “attractive” face is simply prototypical representation of what a face looks like i.e. interpretation as prototype formation and a cogntive averaging process
Mummy’s face
Bushnell, Sai & Mullin (1989)
- preferential looking paradigm with mother vs stranger
- 2 day old infants
- looked at mother 63% of time
Walton et al (1992) replicated with mothers rather than physically present
However, when hair was covered by a shower-cap could not distinguish mother and stranger
Wheeler et al (2011)
Method:
- used eye tracking methodology to investigate whether 6-10 month old Caucasian infants (N=37) have differential scanning patterns for own and other race faces
Results:
- infants spent a similar amount of time looking at own and other race faces
- but with increased age, infants increasingly looked longer at the eyes of own-race faces and less at the mouths of own race faces
Findings suggest experienced based tuning of the infant’s face processing system to optimally process own-race faces
Infants’ knowledge of the world
Cognition vs perception
Cognition: involves mental representations of the world and cognitive processes act upon this
Perception: the ‘here and now’
Jean Piaget
Infants gradually contrasts knowledge (through interacting with their worlds) a constructivist account (of cognition not necessarily perception)
A key aspect of his account is the infant’s ability to maintain a representation of objects that our out of sight - object permanence
- this begins to appear at 9 months but not fully developed until nearly 2 years
Another key aspect was that at 9 months infant’s mental representations are intergrally linked with their previous actions on them resulting in the A not B error at 9 months
Post Piaget
He underestimated infant awareness of object permanence and understanding of the physical world
- his reliance on measuring infants’ actions on objects (e.g. reaching towards)
Violation of expectation
- infants will look longer at ‘impossible’n things - if they recognise that it violates a principle of reality
- Drawbridge study with 5 month olds, truck study with 4 month olds, Speke et al (1992) 2 month olds
3-4 month olds reason about number ofd objects in events
4-7 month olds can appreciate the difference between 2ness and 3ness but not longer numbers
- subitising - appreciating directly a smaller number of objects without counting them consciously
Wynn 91992)
- 4 and 5 month olds have an understanding of addition and subtraction
Revisiting the A not B error
Response preservation? Old habits die hard
Memory limitations> e,g, Harris (1973) found that infants made few errors if allowed to immediately the memory of the object at A predominates the memory of it at B - errors still orccur when object fully visible at B
Place A is a container and the adults communication as such matters
- Topal et al (2009): dogs but not wolves make errors when humans are communicative regarding the hiding
Attention
Frontal cortex maturity and executive function
Quite young infants have knowledge and object permanence and movement
But they are still unable to use this knowledge to guide their actions - initial searched are trial and error searched where the object initially disappeared rather than based on knowledge of the object
Development of frontal cortex allows links between object knowledge and action = success
-‘looking’ behaviour backs this up
