Early Brain Development: Critical and Sensitive Periods
By Inderbir Kaur Sandhu, Ph.D
I heard from my friend that first 3 years of child's life is
very important for brain development. and there are critical
periods and sensitive moments in a child's life for brain
development. Could u please explain more to me. Thanks.
A: This is indeed true and
involves a dynamic interplay of nature and nurture. Research
in early brain development has highlighted up to the age of
three for these periods.
To understand how this really work, I would refer to an
article written by Sara Gable ( State Extension Specialist,
Human Development) 2004 - Nature, Nurture and Early Brain
At birth, the human brain is still preparing for full
operation. The brain's neurons exist mostly apart from one
another. The brain's task for the first 3 years is to
establish and reinforce connections with other neurons.
These connections are formed when impulses are sent and
received between neurons. Axons send messages and dendrites
receive them. These connections form synapses.
As a child develops, the synapses become more complex, like
a tree with more branches and limbs growing. During the
first 3 years of life, the number of neurons stays the same
and the number of synapses increases. After age 3, the
creation of synapses slows until about age 10. Between birth
and age 3, the brain creates more synapses than it needs.
The synapses that are used a lot become a permanent part of
the brain. The synapses that are not used frequently are
eliminated. This is where experience plays an important role
in wiring a young child's brain. Because we want children to
succeed, we need to provide many positive social and
learning opportunities so that the synapses associated with
these experiences become permanent.
How the social and physical environments respond to infants
and toddlers plays a big part in the creation of synapses.
The child's experiences are the stimulation that sparks the
activity between axons and dendrites and creates synapses.
There are essentially two crucial periods for brain
development; the critical periods and the sensitive periods
as you may have heard of. Critical periods represent a time
when a particular part of the body is most easily influenced
or vulnerable to the lack of stimulation or to environmental
effects. For example, if an infant does not see light during
the first few months of life (at least 6 months), nerves
will degenerate and eventually die. This period also
includes prenatal development; what the mother consumes may
have an impact on prenatal development of the foetus.
On the other hand, sensitive periods refer to opportunity
for certain types of learning, that is less precise and a
longer time period compared to critical period. During this
period, if there is a lack of opportunity for a certain type
of learning, it is not gone forever (as it is for critical
periods). Skills can still be acquired at a later stage in
the individualís lifespan. However, skills acquired during
the sensitive period makes the individual better than
another who did not acquire those skills then. For example,
socio-emotional and certain cognitive traits that makes one
person very different from the other. Therefore, this period
is crucial from birth to three years of age.
Informative readings on critical and sensitive periods for
Invest in Kids,
Zero to Three
An article on this for Language Development could be found
Social Issue Reference
Hope that helps a little.