Sensory development

Question 1

Challenges working with infants

Answer 1

• 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

Question 2

What can infants do

Answer 2

• Suck
  
  • Look
  • Have a heartbeat
  • Can later in life, crawl and eventually walk

Question 3

How to use dummy sucking to investigate

Answer 3

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

Question 4

Visual paired comparison task

Answer 4

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

Question 5

What is habituation

Answer 5

a decrease in response to a stimulus after repeated presentation

Question 6

The development of vision

Answer 6

• 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

Question 7

Newborn infants vision

Answer 7

• Things generally look dim and fuzzy
  
  • Infants can see light, shapes and movement
  • Not yet capable of fixation
    Range of vision - approx 30cm

Question 8

1-2 month old infant vision

Answer 8

• Infants can fixate objects
  They can distinguish high contrast colours (black/white but not red/orange)

Question 9

4 month infant vision

Answer 9

• Depth perception improves
  
  • Colour vision is much better
    Infants can now follow objects with their eyes (ie without having to turn their head)

Question 10

8 month old infant vision

Answer 10

• Range of effective vision increases
  Infants can now recognise people across a room

Question 11

Seeing faces

Answer 11

Fantz - show preferential interest in face like stimuli

Question 12

Perceptual narrowing

Answer 12

• 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

Question 13

The other race effect

Answer 13

• 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

Question 14

The development of hearing

Answer 14

• 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

Question 15

Phonemic ability to distinguish

Answer 15

• 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

Question 16

Perceptual narrowing

Answer 16

• 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.

Question 17

Infant directed speech

Answer 17

• 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

Question 18

SUMMARY

Answer 18

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