Between two and three, children become better problem solvers. They are able to make mechanical toys "work" and can put tegether puzzles with just a few pieces. They are tireless explorers of their world. The biggest challenge for children this age comes when they don't yet have the physical skills to make their big ideas work out. Learning to cope with limits and frustration is just another valuable skill that comes out of all that exploration. That's why a parent who offers emotional support to a toddler is also supporting cognitive development.