When Maria Weston's daughter, Lena, was 3 months old, the St. Louis mom started holding her hands up like claws before going in for a tickle. It wasn't long before Lena smiled and kicked the second she saw the hands go up, and now, at 12 months, she laughs in advance.

That excitement your baby shows when you're about to do something she loves means she's learned to predict what'll happen next based on what's happened to her in the past, says Amanda Woodward, Ph.D., a professor of psychology at the University of Maryland, College Park.

Most babies become pros at anticipating what's to come by 12 months, but they begin to develop expectations even earlier, especially as they learn cause and effect -- that their actions have consequences. Try these fun games to help:

Take your baby by the hands, count to three, then pull him to standing. After a few times, you'll see him wiggle as soon as you start counting.

Play peekaboo.  Part of the fun for your baby is knowing that in a second, you'll pop out from behind your hands.

Sing songs with hand motions.  If you always tickle your baby at the end of "Itsy-Bitsy Spider," he'll squeal with glee as soon as he sees the spider climb up the water spout.