4 Stages Of Brain Development And IQ Tests Flashcards
Read the name
First stage?
Pre-natal
・by 5 months, 100 billion neurons have developed
from stem cells and migrated to form the cortex, limbic
system, medulla and brain stem. They then start forming
synapses, enabling them to communicate with each other,
so the foetus starts reacting to sounds at 6 months
・drugs, e.g. alcohol, can affect the development of these connections and cause difficulties with memory, speech or thinking after birth
Second stage?
Childhood
・after birth, 1000 new connections between neurons are formed every second
・the number of synapses in the cortex peaks at around 3 years old - - > unused connections are pruned
Third stage?
Adolescence
・the limbic system (which controls memory and emotion) matures before the pre-frontal cortex (which controls decision-making, social behaviour and impulse control) - - > this difference explains why teenagers take risks more than adults
Fourth stage?
Adulthood
・ the pre-frontal cortex finally matures aged 25, leading to less impulsive behaviour
・as the brain ages, neurodegenerative disorders like Alzheimer’s disease
(problems in memory, thinking and personality) and Parkinson’s disease (affecting
movement and speech) can be caused by certain types of neurons dying.
IQ tests
・intelligence quotient = mental age ÷ actual age (100 was the average - - > it is now a bit higher)
๑tests were first developed around 1900, to identify French school children who needed
more help to learn and to screen US army recruits
๑they tried to measure the ability and potential to think, learn and solve problems
๑Yerkes found that Americans scored higher that recent eastern and southern European
immigrants, and black people scored lower still. This was used to justify racist policies
๑the IQ tests were (and still are) accused of being culturally biased - - > they didn’t take into
account differences in education and experience when measuring intellectual ability
