At age 3 or 4, many children begin telling parents about their dreams. Some children might begin dreaming even earlier, and only talk about it later.
But do newborns dream?
In a classic study in 1966, a research team studied sleep waves in newborns. They discovered that not only do newborns dream (even as early as their first day of their lives), they actually dream more than college students.
The study showed that humans more during the first 2 weeks of life than at any other time. Infants who are 3 to 5 months old dream much more than infants 6 to 12 months old do. Also, 18-month-olds dream almost twice as much as 3-year-olds do. By the age of 3, the amount of time spent dreaming per night is generally in the same range as that of young adults. Each year we dream a little less.
In fact later studies concluded that babies dream even before they are born.