What's more, by 15 months, most toddlers have developed the motor and cognitive skills necessary to carry out the action to be imitated. Children this age are usually mobile and have some hand-eye coordination.
What drives toddler imitation? In part, it's the instant connection that mimicry creates between parent and child. Take Judah flexing his biceps. "Stretching isn't physically rewarding to a 1-year-old," Dr. Nalven says. "It's all about bonding with Daddy."
The attention little imitators receive for their efforts also encourages these performances. When 14-month-old Noa donned her mother's yellow beret and toddled out of the room, her mom cheered and got excited, "so Noa repeated her performance, and we both laughed," recalls Miriam Bloom, of Cambridge, Massachusetts.
Imitation is also a stepping-stone to independence. "As they copy the deeds of adults, toddlers realize, Wow! I can do this! Aren't I great? I'll try it again," Dr. Kessler says. "They learn that they have control." Eventually, 1-year-olds begin not just to imitate but to act out of self-motivation.
For 1-year-olds, imitation follows a four-step process: watching and listening, processing the information, attempting to copy a behavior, and practicing. Language development offers an example. When 1-year-olds form simple words like baba, they're really imitating the sounds they hear around them. Over time, after countless repetitions, they process this information. "Toddlers start to narrow down the sounds to ones that make sense, like Mama for Mommy," Dr. Klein says. Then they keep practicing until they can use the word in context.