Birth-18 months
                     Almost all neuron (nerve cells) are present at         birth but most are not connected in networks.  The         connecting process (synapse formation) is rapid         during this year, with brain activity becoming         closer to adult than newborn by 12 months.  Areas of         greatest growth are sensorimotor, visual cortex and         later the frontal lobes.  Play reflects the         development of brain areas.  This is what Piaget         called “practice play.”
                             Sight, sound, touch, taste, smell: These are         the ways babies learn about the world. This is why         the best infant toys are usually brightly colored         noisemakers. They soon graduate from mobiles (try a         musical one for extra interest) and mirrors (which         they find fascinating) to grasping and holding. Toys         they can manipulate with pleasing effects--activity         quilts with different textures: attachments that         squeak or jingle; rattles; activity bars: soft balls         to drop and retrieve--begin to teach them dexterity         and the concept of cause-and-effect.
                             As babies team to sit up, crawl, stand and then         walk, the possibilities quickly expand They're ready         to experiment with nesting cups, activity boxes,         stacking rings, large blocks, and a little later         with shape-sorters. These toys help develop fine         motor skills and reach relationships among objects.         Cloth or board books, especially intriguing with         pictures of faces or familiar objects, let then,         practice object-recognition and instill basic ideas         of language. Babies and toddlers also love bathtub         toys because they delight in all kinds of water play         such as filling, emptying, and splashing. And as         soon as they're up on their feet, they're ready        to roll with push-pull toys.
                             A word of caution: Be sure any toy for a child         in this age group has no small pieces that can be         removed or broken off and swallowed, no sharp edges         or points, and is made of materials.
        18         months-3 years
                             During this age the synapses continue to expand         and reach about 1,000 trillion - twice the density         of the adult brain.  (Pruning takes place later to         reduce the number).  The toddler brain is twice as         active as the adult brain.  The structures of the         brain that are sensitive to language and         social-emotional response develop.  Motor         development continues at a rapid pace. 
                         Action is the name of the game for toddlers, who         delight in running, jumping, climbing and riding. A         ride-on toy to zip around on will be a sure-fire         hit- whether it’s a low tricycle or a foot-to-floor         vehicle in a whimsical bus or car design. Low         climbing toys, large balls, and outdoor items like a         sandbox or wading pool are also good choices for         developing gross motor skills.
                             Take-apart toys, pop-up toys mid simple puzzles         gratify toddlers' curiosity about how things work,         reinforcing their eye-hand coordination and         understanding of spatial orientation and cause and         effect. One of the best possible toys is that         time-tested classic, a good block set: it's just         about the most open-ended, mind-expanding toy made         for kids of almost all ages and one that will be         used for years. Another creative, tactile-pleasing         choice is modeling clay. Tambourines, xylophones,         drums and other simple musical instruments are         satisfying noisemakers.
                             Again, be sure toys are made of nontoxic         materials, with no sharp edges or points or small         parts that can be removed or broken off and         swallowed.
                3-6 years
                             This is the fastest growth period for the         frontal lobe networks, and speed of processing,         memory, and problem solving is increasing.  The         brain is at 90% of its adult weight by 6 years.
                             Imagination and interaction play starting roles         during the preschool years, and the best toys help         set the stage for developing these skills. Things         that connect with the experiences kids have are the         best for dramatic play.
                             Opt for a generic unstructured item rather than         the single-function brand name version. Play         telephones, kitchen appliances and utensils, tool         sets, medical kits. vehicles. dress-up clothes and,         of course, baby dolls, as well as toy people and         animals all spark the scenarios kids like to         construct. Finger or hand puppets offer another way         of acting out and mastering day-to-day experiences.
                             The language and social skills practiced         through make-believe games come into play as         preschoolers interact more and more. Early board         games introduce the concept of taking turns and         sharing with others, while letter -, word- and         number-recognition toys and games reinforce math and         language learning. So, of course, do books,         especially if they're chosen to match the child's         interests.
                             Art materials (clay, crayons markets, paints,         collage materials) are another creative favorite         with most children in this age group. And don't         forget jump ropes, larger tricycles and that         always-memorable first bike with training wheels.
                     The synaptic connections in motor and sensory         areas are firmly established and the process of         elimination synapses (pruning) in these areas has         begun.  Because of the activity in higher brain         "control" centers, children increase in levels of         attention and ability to inhibit impulses.
                             By the time they're in the primary grades,         children have gotten the hang of basic dexterity,         language, and social skills; now they're eager to         practice and refine them. They like to challenge         themselves, intellectually, with puzzles and games         that test their growing knowledge or involve         strategy (checkers, card games), and physically,         with pick-up sticks, jacks, roller skates, pogo         sticks, and ball games.
                             There are lots of other imaginative options         than can broaden this group's horizons, from craft         sets for making jewelry and puppets to a microscope,         nature-study kit, or a printing set. You might also         turn the passion for collecting that many children         develop at this age into a special link between the         two of you: for example, by adding a special doll or         action figure or set of stamps.
                     The maturation of the frontal lobe continues in         adolescence.  (Pruning continues during the stage).         The Speed and efficiency of thought increases,         spatial working memory improves, emotional         regulation becomes greater, planning and problem         solving skills increase, and scientific reasoning         and ability to understand one's own thinking         develops.  Play becomes sophisticated and         increasingly symbolic.
                             Play in the preteen years often is a group         production, and the pastimes kids prefer reflect         that. Many complex head games for several players,         and equipment for organized sports or activities         (baseball bat and glove, racket/paddle games) is         often a hit. Electronic games are also popular,         played either on en masse or by competitive turns.        
                             At the same time, preteens lavish lots of time         and concentration on individual interests, which         might include books, music elaborate construction of         model- building sets, mature tools, sewing kits and         paints. By this age their tastes and skills are         pretty well defined, so targeting toy and         entertainment purchases to likes and abilities of         each child is important.
credit by http://www.childdevelopmentinfo.com/development/pl2.htm