Ongoing brain growth

Although the brain of a 5 years old has already reached 90% of its adult size a number of distinctive growth phases remain to be completed.

At 6 to 8 years old, a growth spurt in the brain coincides with the time when the child is refining their fine motor skills and developing their hand-eye coordination. Around the age of 11 years old, a second growth spurt involves the frontal lobe of the brain, increasing the young person’s ability to develop logic, planning and reasoning abilities. Recent research suggests that another growth spurt at around the age of 18 to 19 years of age involves the prefrontal cortex, associated with decision-making skills and information analysis. The limbic system, or emotional brain, is also remodelling itself resulting in changes in emotional sensitivity and reactivity at this time.

Ongoing synaptogenesis, myelination and synaptic pruning occur throughout adolescence. Neurones sited within the sensory, intellectual or motor areas of the brain undergo further myelination resulting in faster nerve communication providing the basis for a greater cognitive and motor functionality. Around 12 years of age, neurones within an area of the brain called the hippocampus also become myelinated. The hippocampus is concerned with short-term memory and the consolidation and recall of memories from the long-term memory.

So, the development of reasoning abilities and the ability to use memory is not complete until late adolescence which may explain why young teenagers appear to be inconsistent in controlling their impulses and emotions, and why their ability to judge a situation can be poor.