WHY do we nod our heads for 'YES' and shake it for 'NO'

WHY do we nod our heads for 'YES' and shake it for 'NO' ?


             There is a reason behind everything. The best explanation for the answer comes from 'Origin of Species'.  Charles Darwin himself.


                   He related the gestures to a baby's nursing habits. The forward head motion, or nod, is supposedly a breast-seeking pattern while shaking the head from side to side is a breast-rejecting motion. That is, in the first instance, the baby is saying 'YES' and in the second it is saying 'NO'.

This is confirmed by the fact that a baby born deaf and blind will nod for 'YES' and shake its head for 'NO'


See there is  a reason behind everything.