Critical Periods

The brain is very adaptable, however there are situations in which there is a limited window for development. “Critical periods” are a time during early life when the development & maturation of brain function is strongly dependent on experience or environmental input.

Most evidence for critical periods comes from examples where the absence of experience (e.g. a child raised by monkeys in the forest who never heard spoken language) prevents the development of associated brain functions. In these examples, later exposure does not appear to make up for the earlier loss.

Abilities that have critical periods for development include:

Vision

In humans, depth perception develops around 4 months old. If for some reason an infant does not receive adequate visual input in both eyes prior to this (e.g., eye injury or surgeries) it will not develop.

Music

Absolute or ‘perfect’ pitch appears to be associated with early musical training. In a large scale survey 40% of respondents who began music lessons before age 4 were shown to have perfect pitch. But, the older respondents were when they started lessons, the less likely they were to have developed this capacity.

Language

Learning a second (or third) language is easier if done so before puberty, or more specifically before the age of 7. The research shows that after this age, language acquisition is generally much more difficult & usually less successful. This is why learning a new language can be so difficult during adulthood, although certainly not impossible. It is also why adults who have learned another language will typically speak with an accent, but children can do so fluently & with no accent.

It’s no surprise that early exposure has its benefits. We see this in sport, music, dance or really with any skill. This is because while the brain is plastic & malleable, we cannot be an expert at everything. We must pick & choose where to direct our energies.

The best way to help your child flourish in any field is to let them follow their interests & see where it takes them!

References: Hubel & Weisel 1963, Cohen & Baird 1990, Singleton 1995