PH = (e² + ve²)(d²) + (cg + dr)² + π{(4< s >2)(4< p >2)}² + (vi + t + te)² + {(4< c >2)(4< du >2)}²

Where (e) is eye contact (1=none; 5=direct) 5; (ve) is verbal greeting (1=totally inappropriate; 5=totally appropriate) 5; (d) is Duchenne smile - smiling in eyes and mouth, plus symmetry on both sides of face, and slower offset (1=totally non-Duchenne smile (false smile); 5=totally Duchenne) 5; (cg) completeness of grip (1=very incomplete; 5=full) 5; (dr) is dryness of hand (1=damp; 5=dry) 4; (s) is strength (1= weak; 5=strong) 3; (p) is position of hand (1=back towards own body; 5=other person's bodily zone) 3; (vi) is vigour (1=too low/too high; 5=mid) 3; (t) is temperature of hands (1=too cold/too hot; 5=mid) 3; (te) is texture of hands (5=mid; 1=too rough/too smooth) 3; (c) is control (1=low; 5=high) 3; (du) is duration (1= brief; 5=long) 3.

It's that easy!

Perhaps just as interesting is the fact that this formula was arrived at by University of Manchester scientists hired by Chevrolet "as part of a handshake training guide for its staff to prepare them ahead of the launch of the new 5 Year Promise offer, which aims to offer peace of mind and reassurance to its customers."

Now excuse us while we go practice with our best friend for the rest of our useful lives.

[Image courtesy of Aidan_Jones]