Ask the Brains; March / April 2011; Scientific American Mind; by Paul Li; Daniel Lametti; 1 Page(s)

When do human beings start to dream?
—William Keith, Houston, Tex.

Paul Li, lecturer of cognitive science at the University of California, Berkeley, replies: Pinpointing when humans begin to dream remains an elusive challenge, although scientists have some ideas. There are researchers who argue that dreams originate as early as in the mother’s womb, whereas others posit that they first occur when a child’s brain becomes more developed, around five to seven years old.