My son was born in 34.5 weeks. Now, he is 4.5 months old. Gaining weight normally. Problem - He looks around at certain objects curtains, shadows, rattles and our hands while we snap or make gestures with hands. But he doesn't make eye contact or not look at our faces. Even if we come in front of him leaving him no choice then also he prefer to look elsewhere (ignore us) but not our face or eyes. When he is looking rattle or something else, he follows that object if we move that, he tract that object. Is this normal? What should we do?