Child development research shows that screen time - any form - is not beneficial for during the first several years. (even if it is 'educational', it will do nothing to aid the child's development in any way). No wonder Disney, owner of Baby Einstein, was required to reimburse families up to the cost of four DVDs, for falsely advertising that the Baby Einstein DVDs would improve or develop the child's intellect.

two year olds are great with marbles when supervised. most of them have long abandoned the idea of putting non-food into their mouths by this age, and their development thrives on supervision and interaction regardless of what materials they are exploring.