Development of Sensory Perception Flashcards
What are the 5 senses?
Visual
Auditory (hearing)
Gustatory (taste)
olfactory (small)
tactile-haptic (touch)
What is the preferential looking method?
Babies prefer to look at something rather than nothing
A display of black and white stripes on one side and then a blank display next to it
If the baby prefers to look at the striped display then we can infer the baby sees them
We can use EGGs alongside this
When can babies see colour? How was this tested?
The preferential looking method has been used to determine what age infants see colours
Infants prefer to look at coloured imagery vs uncoloured
By 1-2 months, babies can see greens and reds
By 3-4 months, babies see all 4 of the basic colours: red, yellow, green , blue
How do we know that the infants auditory channels are working?
Babies will turn their eyes and head towards sounds they find pleasant or interesting
The high amplitude sucking test will be used as well, when the sucking rate increases they want to keep hearing this sound.
When the sucking rate declines, the researcher can change the sound and the sucking rate will pick backup
This shows the baby can discriminate between the 2 sounds
A correct head turn results in visual reinforcement from the direction of the audio speaker
How important is touch in infancy?
Skin to skin contact is important to reduce stress and to improve development
Touch can also been used for learning, to acquire knowledge about the properties of objects
e.g. grasping tubes differently depending on their weight
How important is taste in infancy?
4 basic tastes: sweet, sour, salt and bitter
Dislike bitter tasting foods as these could be toxic
Prefer sweet taste as the mother’s milk is sweet
Innate bias to breast milk, more activity in the orbito-frontal cortex for breast milk VS formula milk
Muscles relax when baby tastes something sweet
Purse lips when they have tastes something sour
This changes with age
How did babies develop during the Pleistocene epoch?
Hamo Sapiens lived in the Pleistocene epoch
During this epoch, the infants were never left alone so they were protected by their parents at all times from predators
Infants developed a relationship with their mother through skin to skin contact and attention to the infant’s signals
What are the historical views of infancy?
Plato believed in the nature debate
Innate knowledge
Aristotle believed in the nurture debate
‘blank slate’
Welfare of society was dependent on raising children well
Where can the earliest stage of neural development be found?
Prenatally
Baby can support basic sensory and motor functions
10-26 weeks post contraception, the rate of brain growth is about 25,000 cells a minute
What are the sensory capabilities at birth?
All sensory processes are functioning at birth but their development is heterochronous
What is accommodation?
Accommodation describes the changes in lens shape that change focus
Promotes attention to important stimuli such as the mother’s face and breast, and limits distractions to other objects
How developed is the infant’s visual system when born?
Visual system is automatically present at birth
Cornea, lens and retina is not mature
Vision is blurry
See mother’s face from 30cm away
Coordinated eye movements are not possible
What is pattern perception?
Infants are presented different visual forms
They prefer to look at faces, then complex patterns and lastly, plain stimuli
What is the evidence for an infant’s visual organisation?
Infants were habituated to a square
When tested, Infants looked less at an illusory square suggesting they perceive its form
Habituated infants to a rod moving behind a box
Infants expected to see a whole rod when the block was removed
When shown a broken rod, infants were surprised at this suggesting they expected to see a whole rod
How does human hearing work?
Vibrating objects move air molecules that surround them
This in turn moves adjacent molecules
The resulting areas of rarefaction and compression are transmitted as sound waves
Perceive frequencies between 20Hz and 20,000Hz
What happens during Prenatal auditory development?
At 19 weeks post contraception auditory function is present
Amniotic fluid in the ear canal attenuates auditory response
Fetal hearing occurs via bone conduction
Most responsive to low frequency sounds
What happens during Postnatal auditory development?
After birth, airborne soundwaves become accessible to the newborn
They can then hear higher frequency sounds
Access to time and amplitude differences between the 2 ears that help localise sounds
Functional at birth and respond to sound
Prefer the sound of speech to other sounds, particularly the mothers voice
2 days: prefer their own language to foreign language
2 months: distinguish basic components of language called phonemes
What happens if an infant is allergic to sweet tasting food or is hungry?
Their taste can be learned depending on whether their initial reaction was positive or negative
e.g. baby is allergic to cow’s milk (sweet tasting) will quickly prefer soy-based milk substitutes (sour tasting)
Food previously disliked can be liked when faced with hunger
How is smell important for the mother-infant bond?
Helps mothers and babies recognise each other
Identify edible foods e.g. lactating mother
Smell of chocolate or banana can cause a relaxed facial expression
Smell of rotten food makes an infant frown
The smell and taste of the amniotic fluid is influenced by the mother’s diet
At birth, an infant will prefer the mother’s amniotic fluid relative to a stranger’s fluid
What French study showed an infants developed sense of smell in relation to its mother?
France
Tested an infants preference for aniseed- a common ingredient in that region
Infants of the mother who liked aniseed liked the odour
Infants of the mother who disliked aniseed disliked the odour
When does touch develop?
Touch is well developed at birth
Particularly in the mouth, palm, soles of feet
Infants respond positively to touch e.g. induces smiles
Newborns habituate to objects held in their hand
How are reflexes useful?
Eye blink: protection
Rooting & sucking: nursing
Stepping & crawling: early components of locomotion
Moro & grasping: used to grip the mother
When do reflexes phase out? Why?
Disappear by 6 months of age
Only the eye blink reflex stays
Reflexes phase out as behaviour becomes more controlled due to development of the cerebral cortex
Why is it important to test reflexes in infancy?
Absent or weak reflexes can inform parents about central nervous system function
Persistence reflexes can indicate damage to cerebral cortex
