Infancy & Brain Development Flashcards
(44 cards)
Which senses are more developed in infants at birth?
Smell, hearing and taste.
Are infants’ sense of smell well developed at birth? Explain why or why not.
It is. They turn towards pleasant odours, and turn away in disgust at non-pleasing odours (vinegar), even at 6 weeks old.
Are infants’ sense of taste well developed at birth? Explain why or why not.
Yes. Infants suck vigorously on sweet solution, but react in disgust at vinegar solution.
Are infants’ hearing well developed at birth? Why or why not?
Yes - prenatal ability. There are changes in interburst intervals when a familiar story / mother’s voice is heard, indicating recognition from when in the womb.
Children exposed to non-native sounds recognised the other language, whilst control babies didn’t.
Are infants’ vision well developed at birth? Why or why not?
No. Acuity is achieved more at 6 - 8 months. They focus best when objects are 30cm away, and have preferential-looking technique.
Explain the trajectory of an infant’s colour perception.
1 month: red & green cones
2 months: colour discrimination
4 months: categorical colour perception
Elaborate on an infant’s depth perception.
They use different cues to perceive depth, most of which used by 6 - 7 months of age
How does the schedule of vision impact human development?
Since vision is our primary way of interacting with the world, our human dev slows down when we can’t see things.
Describe the schedule of an infant’s physical ability.
1 - 3 months: arm moves in direction of object, but closes hand before it reaches it.
3 - 4 months: arm moves towards and grasps object
7 - 8 months: crawling
1 year: walking!
How does the schedule of physical ability influence human development?
Our development becomes dependent on other people to bring our environment to us, so we can interact with it.
Babies born over __ months are more likely to survive.
6
Compare the development of chimps’ brains to human ones.
Chimp’s brains develop at a faster rate compared to human ones.
Why is the human brain so immature at birth?
A mature brain would prevent the baby’s head from exiting the birth canal.
How do our brains grow bigger?
Neurons grow larger and neural connections strengthen through synaptogenesis, rather than multiply.
What is synaptogenesis?
The forming of synapses; axonal and dendritic fibres grow
What are glial cells?
They:
- surround and hold neurons in place
- supply oxygen & nutrients to neurons
- help form myelin
- remove dead neurons
- assist synaptic pruning
What is the ratio of glial cells to neurons in adult brains?
9:1 / 50:1
What happens to a human’s synaptic density as they age?
It follows a curvilinear trend (think Yerkes-Dodson law). Less neural connections, but more efficient as unused neural pathways die off
How are neural connections formed / strengthened? What does this mean for human development?
Interactions with the world, meaning that there are prime windows for learning. Brain circuitry NOT pre-determined by DNA
What are three examples of how experience affects brain development?
1) Correction for strabismus
- before 6 years old, less-favoured eye needs to be trained so its synapses are not lost to pruning
2) Phoneme perception
- perceptual narrowing: perception narrows based on environmental experiences; babies sound different only after 6 months, depending on the language they learn
3) Emotional closeness
- children who experience nurture and care are less likely to respond to stressful situations with raised cortisol levels, which can impact neural development
Describe the progression of synaptic development.
By 2 years: same number of synapses as an adult
By 3, till 13 years old: x2 number of synapses in an adult, with regular addition and deletions
Fewer changes in hard-wired areas, such as brainstem. More dramatic changes in cerebral cortex
What abilities is the cerebral cortex responsible for? What do dramatic changes in this cortex imply about development?
Higher order thinking such as planning, problem solving, responding empathically to other people, etc.
Development is slow, as the cortex for high level thinking undergoes changes as we grow.
When is synaptic pruning most active?
In our 20s!!!
33 synapses eliminated in the cerebral cortex every second. :O
What did PET scans reveal about children in Romanian orphanages?
Brain development is non-linear; prime times for acquiring diff kinds of knowledge & skills (they were deprived of care and love)
