By age three, the brain has formed about 1,000 trillion synapses, which is twice as many as adults. As the synapses in a child’s brain are strengthened through repeated experiences, connections and pathways are formed that structure the way a child learns. If a pathway is not used, it’s eliminated based on the “use it or lose it” principle. Things that a child does only once will have very little influence on brain development. When a connection is used repeatedly in the early years, it becomes permanent.