Does Your Baby... At 4 Months: Follow and react to bright colors, movement, and objects? Turn toward sounds? Show interest in watching people’s faces? Smile back when you smile? At 6 Months: Relate to you with real joy? Smile often while playing with you? Coo or babble when happy? Cry when unhappy? At 9 Months: Smile and laugh while looking at you? Exchange back-and-forth smiles, loving faces, and other expressions with you? Exchange back-and-forth sounds with you? Exchange back-and-forth gestures with you, such as giving, taking, and reaching? At 12 Months: Use a few gestures, one after another, to get needs met, like giving, showing, reaching, waving, and pointing? Play peek-a-boo, patty cake, or other social games? Make sounds, like “ma,” “ba,” “na,” “da,” and “ga?” Turn to the person speaking when his/her name is called? At 15 Months: Exchange with you many back-and-forth smiles, sounds, and gestures in a row? Use pointing or other “showing” ge...