When children play, they are first of all active. They are doing something with their eyes, their hands, sometimes their whole bodies. They manipulate objects, sometimes over and over with surprising repetitiveness. They tend to explore objects with all their senses, not just one or two. For example, give a 3-month-old baby a rattle and watch all that she does with it—she shakes it and listens to its sound, she transfers it from one hand to the other and repeats the procedure, she brings it to her mouth and 'tastes' it, she drops it and watches where it goes. Without this opportunity to act on their toys and to explore them with all of their senses, the learning that is possible will be restricted.
Along with the skills of eye-hand coordination and control that come from playing with toys will come a fantastic amount of concept development—understanding the meaning of relationships and intrinsic characteristics of objects. A child who tries to put a big puzzle piece into a small recess learns a lot about 'big' and 'little.' A child who tries to roll a car on the dining table and is told that he can play with it 'under' the table but not 'on' the table learns to understand concepts of position. And one who hits herself one time with a wooden block and another time with a hollow plastic block learns some very practical information about 'hard' and 'soft.' There are countless other examples.
The skills that are developed in play mature along with a child. And though the level and complexity of toys will change as a child ages, the skills acquired and rehearsed with the early ones will comfortably move along to the next level.
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.