"The shapes, colors, and movement will fascinate him," says Dorothy Singer, a developmental psychologist at Yale University. Place the mobile no more than 12 to 18 inches from his face, since that's as far as a newborn can see. Once he can sit up (at around 6 to 8 months), reach it, and possibly become entangled in it, remove it from the crib and mount it higher up.
To maximize viewing pleasure, select a mobile with:
Young babies are drawn to contrasts, so a black-and-white model is ideal at first. Starting at 6 to 8 weeks, babies begin to see and be attracted to bright, primary colors. (Skip pastels for now -- it's not until 6 or 7 months that infants respond to such subtle shades.) "Vivid hues help develop a baby's visual ability," says Singer. "As the mobile moves, he'll track it and learn how to focus."
The best mobiles are designed to be seen from your baby's point of view: The patterns on the objects face downward, not outward toward an adult's line of vision.
Babies are born with an innate love of faces, whether animal or human, real or illustrated. When Madeline McCarthy was 6 weeks old, her mom, Kathy Kelleher, of Santa Monica, CA, hung a mobile that featured a baby-safe mirror. "Madeline loved watching her face move," she says.
Mobiles that automatically twirl or play music offer more stimulation than the silent, static variety. But if you opt for a stationary unit, you can always give it a gentle nudge or open a window and let it get some natural play in the breeze.