According to the books, about six weeks. BUUUT, every baby is different, despite what the books say! I'd say it happens slowly over a period of time. I know it's controversial, but I'm a fan of a flexible schedule during the day. I started out with a 2.5 hour schedule, then to 3. My baby learned to expect feedings at specific times, and no longer cried for them, except on rare occasions (in which case I fed him). Then I leave him alone to sleep at night. When he does wake up, I the lights low (before I learned how to do it all in the dark). I don't talk to him or play with him during that time, just keep the stimulation to an ABSOLUTE MINIMUM! I think what happens is when a baby learns to depend on regular feedings and not demand them, then he's less likely to do it at night. He still will, but he'll learn there's a difference between night and day. Good luck!
at 10:07 PM on Jan. 28, 2010