Seriously, I believe in limiting who young children have to emulate in all areas. Books, TV and movies, and real life. Controversial as it is, I do noy feel a bad influence should have unlimited time with a young child, even if grandparent or parent. I can read what my child reads, and decide if the characters are those I think he can benefit from spending time with. If the TV is simply on, I am not likely to know who he is spending time with and learning from. Every parent is free to make his or her own choices. Mine are to limit TV.
Did the OP ever answer the question about the child's attention span?