3.4 Relating Brain Growth to Cognitive Development

The years between birth and three years is a period of rapid brain growth. It is also a period of rapid learning and behavioral changes. Blakemore and Frith summarized some key correlates of behavior and brain development. As the visual cortex shows a proliferation of synaptogenesis around two months, we note a decrease in infantile reflexes and stronger visual explorations of the environment. Motor and visual-motor milestones increase through infancy. The auditory system is also partially developed at birth and shows increasing specialization through the first year.  Newborns are especially responsive to the sounds of human voices, and in particular the sound of their own mother’s voice. By the eighth month, infants who initially respond to phonemes of all languages, respond primarily to the sounds of their own language. Brain development is strongly related to language development, an idea promoted by Lenneberg (1967). Kolb,Wishaw, and Teskey (2019) have related brain growth changes to changes in cognitive development as represented by Piaget’s theory. They noted that the brain does not grow in a smooth uniform progression, rather there are irregular periods of growth spurts. There is a rapid period of brain growth from 3-10 months, with the brain increasing by 30% in weight. Other brain growth spurts occur between 2-4 years, 6-8 years, 10-12 years and at puberty. These growth spurts do not reflect the appearance of new neurons, but rather an increase in synaptic density and glial growth. In addition, there is an increase in the blood vessels that bring nutrients and aid in metabolism related to increased brain activity. Kolb et al. (2019) point out the pre-pubertal growth spurts correspond quite well with the stages of Piaget’s cognitive development theory.

Adolescence is also a period of rapid growth and a change in the way that children think away from more concrete thinking, to a more developed style of critical and integrative thinking that accompanies the changes in the growth in the frontal cortex.

Sensitive Growth periods

Much of learning in infancy and through toddlerhood occurs during a sensitive period. These are times in development when learning is occurs at its optimum time.