Sensory development Flashcards
Challenges working with infants
- Infants can’t talk, and understand little or no language
- They’re often not capable of producing complex or organised behaviour
- They often can’t even move around
- They can get grumpy pretty quick
- We need to use methods suitable for non-linguistic populations
- We need lots of help from parents
- We need to take advantage of whatever behaviours or dispositions infants possess
What can infants do
- Suck
- Look
- Have a heartbeat
- Can later in life, crawl and eventually walk
How to use dummy sucking to investigate
Infants are given a dummy to suck, and a baseline sucking rate is established
Then we show infants a stimulus, and see if the sucking rate changes
Sucking more - excited
No change in sucking rate = not noticed anything different
When the array changes from 3 to 5 dots = no change means infant doesn’t distinguish between 3 items and 5 items. Change in sucking rate = infant is able to see a difference between 3 and 5 items
Visual paired comparison task
The proportion of time spent looking at the new picture lets us figure out
- Can they tell that two things are different?
Can they remember the first picture
This method relies on habituation
What is habituation
a decrease in response to a stimulus after repeated presentation
The development of vision
- It takes one year for the basic perceptual aspects of the human visual system to fully develop
- The neural parts of the visual system develop during gestation
Though it’s not until birth that visual stimuli are perceived
- The neural parts of the visual system develop during gestation
Newborn infants vision
- Things generally look dim and fuzzy
- Infants can see light, shapes and movement
- Not yet capable of fixation
Range of vision - approx 30cm
1-2 month old infant vision
- Infants can fixate objects
They can distinguish high contrast colours (black/white but not red/orange)
4 month infant vision
- Depth perception improves
- Colour vision is much better
Infants can now follow objects with their eyes (ie without having to turn their head)
- Colour vision is much better
8 month old infant vision
- Range of effective vision increases
Infants can now recognise people across a room
Seeing faces
Fantz - show preferential interest in face like stimuli
Perceptual narrowing
- With experience, infant’s visual perception gets increasingly attuned to regular features of the child’s environment
Very general abilities are more finely tuned following experience, this is particularly seen with facial recognition
The other race effect
- The ‘Other race’ effect - the tendency to more easily recognise faces of the race one is most familiar with (Kelly et al 2007)
- Infants are initially able to discriminate pretty well between the faces they see
They gradually become extremely good at distinguishing between the kinds of faces they see around them
- Infants are initially able to discriminate pretty well between the faces they see
The development of hearing
- Unlike vision, sound can be perceived in the womb prior to birth
- Infants have heartbeats
- From 26 weeks, foetuses show changes in heart rate as a direct response to auditory stimuli (Kisilevsky et al 1992)
- Full term foetuses can recognise their mother’s voice
Phonemic ability to distinguish
- Infants are initially able to distinguish between phonemes that don’t occur in their native language
This ability narrows to sounds contained in their own language
Perceptual narrowing
- Infants gradually exchange their vast potential for processing all types of information
In return for swifter, greater expertise in processing the information they see most often in their environment.
Infant directed speech
- A common way of adapting your speech to have an exaggerated pitch, range and speed (motherese)
- IDS isn’t a completely different way of speaking - its an exaggeration of existing patterns of speech in the language
- It’s thought to help infant’s to extract smaller chunks of language
- IDS is an important first step in infant’s learning language
SUMMARY
To study and understand what infants perceieve about the world - specialist age appropriate techniques are required
These tend to take advantage of behaviours that infants typically produce spontaneously
Visual perception develops rapidly, changing from poor acuity to adult like levels in around 12 months
Infants show a clear preference to orientate towards face like stimuli
They are able to recognise individual faces from birth
Auditory perception begins in the womb - as shown by foetal heart rate studies
At birth, infants recognise surface level features of the language spoken around them
Language learning can be helped by adults using infant directed speech
Both visual and auditory perception become increasingly specialised with experience
This reflects infants become more adapted to their own specific environment
This perceptual information that infants extract from the world around them acts as the basis for conceptual development
These methods form the basis of most of what we know about infant perception
This percpetual learning forms the basis for conceptual development, as we’ll see
