Which stage of life sees the first noticeable slowing of brain activity?

The first noticeable slowing of brain activity occurs during adolescence. This stage marks a time of significant neurological development, where the brain undergoes considerable changes, transitioning from the rapid growth and high levels of brain activity typical in earlier stages like infancy and childhood to a more stabilized and refined brain state.

During adolescence, there is a reduction in the production and pruning of neural connections, which leads to a decreased rate of overall brain activity compared to the earlier years when the brain is growing at an unprecedented pace and forming vast networks of connections. This slowing down is essential for the maturation process, allowing adolescents to develop more sophisticated cognitive skills and emotional regulation. Thus, adolescence is characterized by an optimization of brain activity rather than the rapid changes seen in prior developmental phases.