There's Mozart for the womb, foreign-language CDs for the crib, and now children's furniture for the brain.

Ikea's PS play-furniture line--basically, jungle gyms for indoor use--has a campaign with a "child" (or so the ad makes it appear) talking about how important her parents say it is to "stimulate my sensory impressions and develop my balance, muscles, joints [to] make me learn even more, and faster."

A catalog called One Step Ahead sells a desk it says will encourage "good posture and good study habits."

As with educational toys, when it comes to furniture and design intended to stimulate development, a little goes a long way. Overdoing it can actually interfere with a child's rest and can exacerbate any attention difficulties, child-development experts say.

Bright colors in a nursery appeal to parents because they appear to promote a fun, engaged atmosphere. But "babies need much less bright color than anyone seems to think they do," says Penny Glass, director of the child-development program at Children's National Medical Center.

Faced with a mix of brights, a child stops discriminating among objects. "What brights and multicolors tend to do is arouse and excite but don't encourage them to pay attention and ponder. Everyone needs a little time to ponder, even babies," Glass says.

Babies do like contrasting colors--as simple as black and white--smiling faces, checkerboards, pinwheels, and lamps that cast shadows. If the room carries a soft Beatrix Potter theme, for example, you might add a few high-contrast accessories. A lamp with a cutout shade and an abstract geometric quilt on the wall can give a baby plenty to look at.

Overall, the feel should be soothing.

"The bed should look like a place to sleep, not a place to play. You need the baby to understand what his job is, and that's to go to sleep," Glass says. "That's something that wouldn't change much for any age."

Rocket-ship beds are fun, but they might make bedtime a struggle. When she worked in a pediatric practice, child-development specialist Claire Lerner also saw babies "physically distressed" by mobiles overhead.

"Parents are overwhelmed by marketing of products," says Lerner, who works at Washington-based Zero to Three, a national nonprofit devoted to healthy development in the early years. "Unfortunately, it's produced a lot of anxiety. What is most important is knowing your child and carefully watching and figuring out what is important to them."

Ch ild-development experts can provide insight on when to redecorate a kid's room. One natural point falls around age three, when a child starts to feel a sense of privacy and ownership; the other is in the very early teens, when that sense of privacy expands, according to the American Academy of Child & Adolescent Psychiatry.

One key for children older than three is to provide a place for quiet thinking, reading, and "pondering," the AACAP says. A window seat, a closet with the doors removed and a curtain installed, a space under a canopy, a play tent, or even pillows in a corner can create a private space.

Many parents may be getting adult-size beds for kids too soon. A too-big bed, besides not feeling as secure a space as a smaller one, takes up floor space that a child needs for play, Glass says. "Toddlers use their entire bodies to learn," the AACAP writes.

Child-size furniture, which got a jump start with the Montessori movement, has long been a staple to encourage competence and comfort.

Th ough the way any child's room is designed can affect his or her learning, it's especially true for children with special needs.

Carol Rubacky Sheridan, a Germantown interior decorator, discovered that when her son had some learning disabilities.

"It's important to have an environment that's not only pretty and fun for them but also functional," she says. "And sometimes functional has to trump pretty."

Safety is always a consideration--pieces like blinds and bedposts can easily become hazards. Sheridan keeps things simple, such as using upholstered headboards and cordless shades.

Storage and organization are the biggest challenge, she has found; she suggests clear bins for children with learning disabilities so they can see what's inside. For attention difficulties, keeping the number of available items low and keeping most things in closed drawers, rotating toys in and out of circulation, works well.

In the end, smart children's design is just smart design.

"One of my principles in decorating is not to have things in the room compete with one another for attention, not to be overstimulating in any environment, whether that's the living room or a child's room," Sheridan says.

Ap air of good books on this topic is In My World: Designing Living & Learning Environments for the Young by Ro Logrippo and In My Room: Designing for and With Children by Logrippo and Antonio F. Torrice.

Other helpful sources: Great Minds Start Little from Baby Einstein, Child Care Encyclopedia by Penelope Leach, and Family Almanac by Marguerite Kelly.