This is what parenting.com says about benefit of shape sorter toy:
How about you? what kind of toys you have for your baby?..Shape sorters are classic toddler favorites, and with good reason: They're a fun challenge. By figuring out how to drop each piece into its proper hole, kids learn to categorize and eventually name shapes (a skill they master around age 2). Between 15 and 18 months, most kids will start to develop the hand-eye coordination and problem-solving skills they need to be able to sort, says Natalie Geary, M.D., a developmental pediatrician in New York City.
Link thi post also to Color Connection hosted by Mommy Rose.