The unconcious movement is called a primitive reflex

The baby looks blanky at his/her moms face because he cannot see very well.but he can hear and recognize his parents voice clearly.baby will feel safe to hear moms voice.
Baby moves his arms and legs,clenching a finger when you press on his palm,sucking at anything that touches his lips,are actually unconscious movements,known as primitive reflex of a newborn baby.this movement is inborn skill and helps baby to survive in the world.
In day-to-day life,your baby hears a variety of sounds.sometimes he will suddenly flinch at a relatively small sound,but this is just a primitive reflex,so it is natural.