Babies this age are very curious, so they require constant monitoring. Your child isn't being defiant when he continues to do something even though you've explicitly told him not to -- he's simply too young to know when he's doing something wrong. If he's about to get into a dangerous situation, say "no" clearly to grab his attention. Then distract him, but you can't simply hand him a toy -- you need to create a certain level of excitement to get him involved in another activity with you. As he gets older, he'll learn to stop what he's doing when you say "no." For now, it's best to keep him busy in areas that are safe for him to explore so you won't have to constantly redirect him. --Sally Lee
Updated 2009. Originally published in Child magazine, November 2002.