(supplementary) The *upward* nod of acknowledgement has quite different connotations to the *downward* nod of acknowledgement.
The user of the *upward* nod of acknowledgement displays the nostrils and their contents to the subject, whilst symultaneously looking down on them. It therefore signals disrespect.
The *downward* nodder looks up to the subject, displaying submission to them. It therefore signals respect.
ayon kay Jonners
ika-19 ng Oktubre, 2005