Critical Periods Flashcards
What is a critical period?
A period where the brain is most sensitive to a specific experience
absence of specific stimuli can lead to blindness
lack of exposure to language at an early age may lead to inability to use language
Why is it more thought as a sensitive period?
Use to think critical periods were rigid but not seen as sensitive - not as setting stone
Who came up with this idea?
Lorenz
Imprinting study
When ducks are hatched, they follow the first thing they see for some time - won’t happen if they hatch and see something a day later
evolution purpose - ensure they follow mum to aid survival
What is the human brain sensitive too? 3 broad waves
Senses open in infancy and close tightly
Language critical till around childhood
Higher cognition - window never closes properly
These waves allow children to acquire complex skills
Genie case
Isolated from family, tied to bed, discovered at 13 and very small, not developed, couldn’t walk or talk
Blakemoore and Cooper
Kittens when born kept in the dark with mum apart from a few hours where they were put in a chamber, could only see vertical lines
recorded visual cortex - neurons only fired when shown vertical lines, none would fire when shown horrizontal
Extreme cases of abuse or neglect
In 1970’s/80’s retarded intellectual development in Romanian orphans
- few toys, little personal interaction, poor nutrition
massive developmental delays and attachment problems
Evolution of the brain
Reptilian brain - controls breathing and heart rate, pons, medula
Paleomammalian - limbic system - amygdala, hippocampus
Neomammalian - cortex - gives us higher function
What happens to a child raised by trauma?
They will have an overactive stress response - overdevelopment in the brainstem and the midbrain - results in a predisposition to act in an aggressive and impulsive way
overdevelopment of brainstem and midbrain (anxiety etc) and underdevelopment of limbic and cortical functions (empathy etc) - predisposes them to violence
What is the optimal developmental experience?
Having a well developed cortex and limbic system
less developed midbrain and brainstem
Are effects of severe abuse reversible?
Only if there is early intervention
