Intellectual development is mostly nonverbal. Do not yet understand cause-effect relationships. Also, egocentric , unable to take the perspective of another person. Child masters conservation . This means that volume, mass, or number don't change even when the shape or appearance changes.
Child is able to think abstractly and to consider hypothetical situations.
Not everyone reaches this stage. May conflict with society's rules and values. Doesn't develop in all people. As the newborn's brain develops, the number of synapses in the brain increases dramatically. Harlow's monkeys, separated from their mother at birth, were given a choice of a wire mesh mother or a warm, soft terry cloth mother.