Lecture 9: Sensory and Motor Development 1 Flashcards
Learning Objectives:
- Working with young children
- Vision in the first year of life
- Hearing in the first year of life
- - - - - - - - - - - - - - - - - -
• Describe the principle methods used in infancy research
• Describe the significant changes that take place during the first year of life
• Critically discuss key studies in infancy research
1: Working with Young Children
Timeline of development
- Foetus (prior to birth)
- Neonate (the first few days post-birth)
- Infant (up to around 2 years)
- Preschooler (c. 2 to 4 years)
- Childhood (5 years to adolesence)
- Adolescent (c. 12 to 18 years)
- Adult (18 years and beyond)
Today focusing on first 3. Looking at newborns helps us to establish what human functions are innate - little experience outside of the womb so useful to investigate what they are capable of right after birth.
1: Working with Young Children
Research using infants
Infants are a source of vital knowledge about human development
- Perception, cognition, social and emotional development, neurology
Researching infancy poses a number of unique challenges:
- Infants can’t talk
- They understand little or no language
- They’re often not capable of producing complex or organised (e.g goal oriented) behaviour
- They often can’t even move around
- They can get grumpy pretty quickly
1: Working with Young Children
How do we overcome the challenges of studying infants?
We use methods suitable for non-linguistic populations
We rely on a lot of help from parents
We take advantage of whatever behaviours or dispositions infants possess
1: Working with Young Children
What can infants do?
Infants can do lots of things:
- look
- grasp
- suck
- can, later in life, crawl and eventually even walk
1: Working with Young Children
Babies suck
Babies are given a dummy to suck, and a baseline sucking rate is established.
Then we show infants a stimulus…
Sucking more = excited
No change in sucking rate = not noticed anything different
Increased activity (sucking) is like a dog wagging it’s tail
1: Working with Young Children
Babies look
Visual Paired Comparison task (VPC)
Babies are shown a picture until they habituate (i.e. get bored of it)
They’re then shown two pictures at once – the old one and a new one
We measure how much they look at the new picture
The proportion of time spent looking at the new picture can tell us:
- Can they tell that two things are different?
- Can they remember the first picture?
- What information have they encoded (i.e. noticed & remembered) from the picture?
–> This is known as the Visual Paired Comparison task (or VPC)
1: Working with Young Children
Working with Newborns
APGAR scale
Birth can be a difficult process - it’s common for newborns to experience issues that need medical management
To check newborns are OK enough to take part in studies, the APGAR scale is used
APGAR score is calculated 0-10
- Appearance: blue – pink
- Pulse: absent – > 100 bpm
- Grimace: no response – grimaces, cries
- Activity: none – all limbs flex
- Respiration: absent – robust cry
Scores of 8 or above are seen as being “OK”
- Vision in the first year of life
Vision overview at the different stages of development
Newborns: Stuff looks pretty fuzzy – can see light, shapes and movement. Not yet capable of fixation. Range of vision c.30cm
1-2 months: Can fixate objects. Can distinguish high-contrast colours (black / white, but not red / orange)
4 months: Depth perception and improved colour vision now apparent. Can follow objects with eyes (i.e. without turning head)
8 months: Visual range increases – can recognise people across a room
1 year: Vision similar to adult levels
- Vision in the first year of life
Seeing Faces
From birth, infants show a preferential interest in face-like stimuli
STUDY: Fantz’s 1961
study showed a series of stimuli to young infants, and observed their looking behaviour
1 image looked like a face, 1 had facial features but arranged wrong, 1 had same outline and overall brightness but no features
Fantz’s findings:
• From the first month, infants showed a small but consistent preference for the face-like configuration
• The same pattern is seen when presenting moving images to newborns – they follow face-like stimuli for longer (Goren et al., 1975)
- Vision in the first year of life
Seeing Specific Faces
Even within a day of birth, newborns are capable of recognising individual faces (look longer at mother than stranger)
Newborn infants’ ability to recognise their mother’s face persists even when olfactory (smell) cues are removed (Bushnell et al., 1989)…
…and when inadvertent visual cues are controlled for (Walton et al., 1992)
It is noteworthy given that infants’ visual acuity is relatively poor (their vision is pretty fuzzy)
- Visual recognition in newborns is unlikely to be accompanied by any explicit cognitive insight
- Though early perception will form the basis for later mental representations
- Vision in the first year of life
Visual Perceptual Narrowing
- Infants’ visual perception becomes increasingly tailored to regular features of the child’s environment
- Very general abilities are more finely tuned following experience – this is particularly seen with facial recognition
- Vision in the first year of life
The “Other Race” Effect
- 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…
…while gradually losing the ability to discriminate between faces that they don’t see often, or at all (Kelly et al., 2007)
e.g. a caucasian baby will find it easier to distinguish between caucasian faces vs asian faces
- Vision in the first year of life
The role of experience in perceptual narrowing
It is possible to retain the ability to discriminate between unfamiliar face types, by shaping the infant’s experience
This has been shown through studies where children read picture books to their infants (Heron-Delaney et al., 2011)
Children were given 70 minutes of picture-book exposure over 3 months – either involving Chinese faces or Caucasian faces
- 9-month-olds shown Chinese faces retained the ability to recognise Chinese faces
- 9-month-olds shown Caucasian faces lost the ability to recognise Chinese faces
Face processing abilities are shaped by experience
- This isn’t unique to human faces
Book-training studies show infants can retain the ability to recognise individuals from other species (Pascalis et al., 2005)
3: Hearing in the first year of life
Early hearing - in the womb
Unlike vision, sound can be perceived in the womb prior to birth
From 26 weeks gestation, foetuses show changes in heart rate as a direct response to auditory stimuli (Kisilevsky et al., 1992)
- They are also able to recogise the sound of their mother’s voice (Kisilevsky et al., 2003)
How much auditory information do babies pick up when they’re in the womb?
