I have found with all toys including balls, interaction with the children is def required. However, by interacting along with the child as they play and explore the many options of the toy, they are also learning so much more than just shoving a toy down the hole. For some reason the ball toys really do seem to ignite a whole new world of "cause and effect" and "problem solving" among many other developmental skills, not to mention they really are fun for all. When I get on the floor with the kids and a light weight ball, we go crazy, we roll it, we toss it, sometimes drop it down a shirt or stick it in a pocket...too cute watching them try and figure how to get it out... balls are a def must IMO, I know they can put in mouth or throw them, but there just seems to be so much more positive than negative. Wash them with sanitizer at the end of the day and always make sure "ball" play is supervised and done correct.