Following birth, a newborn’s brain is flooded with sensory information. As each neuron (in the child’s brain) matures, it sends out multiple branches which increases the number of synaptic contacts. At birth, each neuron has about 2,500 synapses. At three years old, the number of synapses is approximately 15,000 synapses per neuron. This amount is about twice that of the average adult brain. As someone ages, old connections are deleted through a process called synaptic pruning.
Synaptic pruning eliminates weaker synaptic contacts; stronger connections are strengthened. Experience determines which connections are pruned and the ones that have been activated most frequently are preserved. Ineffective or weak connections are "pruned" in much the same way a gardener would prune a tree or bush, creating the desired shape.