You know the shock you feel when you bump into someone, like you're not in control of your body? That's how your baby feels when she first "reaches" for a toy. "When babies begin moving their arms, they don't realize they can use them to touch objects," says Daniela Corbetta, Ph.D., an associate professor of psychology at the University of Tennessee in Knoxville. "But when they unintentionally hit a toy, they think, 'Oh, maybe I can do this again.'?" And they do. Every time your baby swipes for a toy, she's refining the action so that she can better grab it the next time. At 5 to 6 months, babies tend to use two hands to reach for objects; by 8 or 9 months, they know to use two hands for big toys, one hand for small ones.
What you can do: Catch your baby's interest with a variety of toys. After she masters this skill, she'll start to explore objects by putting them in her mouth, so it's important to make sure that what she has in her hands is baby-safe.