Babies to 2-3 months, will smile at the front of his people, adults tease him, he will laugh, and can giggle out loud, out loud laugh is also an important criterion to detect the baby can normal vocalization. The baby will laugh after the adults can often make the baby laugh, love to laugh after the baby grows up more intelligent, personality is also more cheerful, so adults should spend more time with the baby, more interaction with the baby, more make the baby laugh, the baby’s lifelong emotional intelligence development is very beneficial.