Origin of “stroking your head” gesture

People stroke their head or hair when they are comforting themselves, because that’s often how their mother comforted them when they were little.

Origin of flaring nostrils in anger

When angry, nostrils flare to allow more air to oxygenate the body in preparation for fight or flight.

Origin of Smiling

Smiling is a threat gesture for most carnivorous animals, but for primates its done together with other gestures to show submission. When you smile at someone, the animal within is saying "don’t fear me – I’m submissive – I’m no threat to you".

Origin of Headshake for “no”

Shaking of the head to indicate "no" may be a gesture learned in infancy as the baby turns its head from side to side when it wants to reject food when its full. Soon he learns that head shaking is disagreement or a negative attitude.

The Origin of the Salute/ Handshake

The right hand at the brow comes from medieval times when men in armour lifted their visors with an empty right hand to show who they were and that they had no weapon.
We still do this today when we shake right hands and make eye contact as we great each other.

Origin of the 2-finger V-sign

The 2-fingered V-shape signified "up yours" in the UK but it origiates back several centuries to the English archers who used those two fingers in a V-shape to fire their arrows. In those days, when an archer was captured by the enemy, rather than be executed, he had his two shooting fingers removed (ouch!). So it became a popular goading sign for the non-captured British archers to show their enemies the V sign to show them ‘ha! I’ve still got my shooting fingers’.