My son is 16 months old, and he really doesn t look at me, Or really no one. He acknowledge the people around him but then does his own thing and really doesn t interact with people even we we call his name. Very rarely will he stop and look as us after we call him. I know he hears well because when were outside he ll listen to the birds signing or planes passing by and other little noises. I try to read him books and he s not interested. I have 2 older kids and they were not like this, I would talk to them and read to them and they would interact with me and people round them, but my toddler is not like that.. Should I be concern, as to maybe some type of down syntrum?