Discuss the concept that the human brain doubles in time.

In answering your question I am assuming you are referring
to brain growth and development from birth onward, not during intrauterine fetal
life.

The growth and development of the human brain does
indeed double with time, however there are marked differences in the doubling time among
the myriad functions of the brain compared to the physical growth (enlargement) of the
brain.

The infantile brain is said to be “plastic”.  This
is positive in that the plastic brain has a greater capacity for learning and
adaptation.  On the negative side, however, the plastic brain is susceptible to
developmental defects in non-nurturing or hostile
environments.

In human brain growth and development,
genetics are important for the formation of proper brain structure and wiring. 
Environmental effects on brain development determine the brain’s ability to properly
function and adapt.

In terms of doubling times for the
brain, here are some facts:

Brain Size:  Newborn = ¼ adult
size, Age 3 = 80%, age 5 = 90%.

Number of neurons:  100
billion.  Peak occurs before
birth.

Speed of Neuroprocessing:  slow in infancy, maximum
at age 15, gradual decline thereafter.

Language:
development of language skill begins at 5 years and is essentially completed by
puberty.

Other skills:  there probably are not specific
critical developmental periods for each and every brain function.  Most brain functions
depend on correct development and function of sensory organs, such as vision for
hand-eye coordination and perception.

Important co-factors
that affect growth and development of the brain are nutrition, stimulation (sensory,
auditory and visual), nurturing and exposure to
language.

The end result of brain development is the
acquisition of normal abilities in perception, memory, thinking and feeling
(emotions).

Please see the reference for a detailed
description and explanation of the complexities of human brain growth and
development.