infant perceptual and motor development Flashcards
(17 cards)
Key points about development of vision
The least developed sense at birth
Visual acuity is the sharpness of vision and clarity that fine details can be detected
A new born can distinguish visual forms only if close enough.
They have 20/400 vision
Visual acuity vs colour perception
Visual acuity:
6 months- approximated normal adult vision
8 months- More interest in distant object and small ones
Colour perception:
Newborn: prefer colour to grey
2-4 months: see full colour spectrum
The preferential looking method and pattern perception:
Looking chamber fantz 1961: infant lies down and is presented with 2 stimuli, if infant spends more time looking at one over the other, they know the items are different.
Pattern perception: newborns prefer patters to plain stimuli and at 2 month they prefer more complex ones. So is there any benefit of different toy patterns past 6 months?
What is visual scanning
An eye tracking method, found they prefer high-contrast areas
At one month: look at edges
2 months: internal features and have sticky fixations
6 months: adult-like scanning and can orient attention.
(maurer and Salapatek 1976)
How children see shapes and how it changes:
Before 4 months, they perceive shapes by looking at the edges and corners. By 4 months, they can see subjective contours and shapes that do not have clear edges. This improves over first year.
At 12 months, they can recognise incomplete line drawings-Rose et al 1997
Habituation is a form of learning reflected in a decrease in the strength of response to a repeated stimulus
Facial perception in infants
Newborns track faces more than other stimuli (Johnson et al 1991)
Nurture- this bias gives them much experience
2-4 months: prefer more complex facial stimuli and prefer mother’s face and can discriminate between faces
5-12 months: can discriminate emotional expressions
Depth perception in infants
1) Binocular cue develops between 3-5 months
- (disparity where brain perceives depth when combining slightly different angle from each eye)
2) Kinetic cues develop at one month
- (Motion parallax is knowing that objects that are behind and not moving are far away and those moving quickly are close)
3) Pictorial cues develop at 5-7 months
- Interposition: an object that overlaps another appears closer
- Linear perspective: parallel lines appear to converge in distance
Visual cliff: gibson and walk 1960
Compare depth perception in infants of different species
Humans have more crawling experience and are so more avoidant of the cliff
What happens when visual development is interrupted
1 month old Kitten deprived of light for 3-4 days, their visual centres do not develop normally.
- At one week deprivation, damage is severe and permanent
- One month old kittens deprived of light for a few days show degermation in relation brain regions and damage to visual perception is permanent
In humans, infantile cataracts can cause sensory deprivation. If left untreated for initial 6 months, infants can be impaired for life.
The critical period for binocular function begins at 6 months and peaks from 1-2 years
Babies with dense cataracts, their vision may develop normally if reversed early.
Key points about hearing
More mature than vision at birth.
Newborns are less sensitive than adults to quietest sounds and more sensitive to sounds in a range of speech
Clifton 1992- children develop localisation to adult level at 2 years. At 7 months, they know when sounding object in dark is within reach.
Development of music vs speech
Music: prefer music to non-melodic sounds.
From 4-6 months prefer more common chords
6 months: distinguish western vs non-western music scales
Speech: prefer to hear infant-directed speech (higher pitch and elongated words)
Prefer voice of mother over stranger
Prefer familiar rhyme heard during last 6 weeks of pregnancy than novel rhyme.
What happens when hearing development is interrupted
- Congenital hearing loss results in anatomical differences in brain structure
- Delayed/absent/impaired speech and language development
- May be partially reversed through cochlear implant
Development of taste
Newborns can detect 4 main tastes from 2 hours old and prefer sweet possibly due to survival values and avoiding physical danger
At 4 months, prefer salty foods to plain.
Development of smell
Is it innate? Universal expressions for pleasant vs unpleasant odours
Newborns prefer familiar odours such as amniotic fluid, breast milk and moth’s perfume.
Touch key points
Newborns can feel pressure, texture, temperature and moisture and their face cand and feet are most sensitive.
They have the same number of pain receptors as adults
Used to explore environment and are able to discriminate objects through their feel.
Develop reflexes such as rooting, sucking, swallowing and swimming. Some non-essential ones are: moro (startle), gripping, stepping etc.
Cot death or Sudden Infant Death Syndrome (SIDS)
- Unexplained sudden death of infant under a year usually during sleep
- Critical period risk is 1-4 months where reflexes wane.
- Baby may not move away from items in cot.
- Cot death more likely where there are external stressors such as exposure to smoking or co-sleeping.
Motor development patterns
1) Cephalocaudal (head to tail) motor control proceeds from head to toe
2) Proximodistal (near to far) motor control proceeds from trunk to limbs
Fine motor skills:
Proximodistal: arms hands and fingers
In newborns, it is displayed as pre-reaching
3-4 months it is goal directed reaching
5 months: transferring object between hands and the grasp anticipates the object orientation
9 months: anticipate object size
18 months: tool use and pincer grasp
