Saturday, 14 August 2010

The Handshaking Lemma

Professor Geoffrey Beattie of the University of Manchester has given us mathematical formula for the perfect handshake. For some reason, all of the articles which contain said formula seem to include it as a picture, rather than writing it out in words, so I'll do the same thing (mostly because I don't know how or if it's possible to get LaTeX to work in blogger... does wordpress do it?

Just in case you're wondering what all those symbols mean...

(e) is eye contact (1=none; 5=direct); 
(ve) is verbal greeting (1=totally inappropriate; 5=totally appropriate); 
(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); 
(cg) completeness of grip (1=very incomplete; 5=full); 
(dr) is dryness of hand (1=damp; 5=dry); 
(s) is strength (1= weak; 5=strong); 
(p) is position of hand (1=back towards own body; 5=other person's bodily zone); 
(vi) is vigour (1=too low/too high; 5=mid) 
(t) is temperature of hands (1=too cold/too hot; 5=mid); 
(te) is texture of hands (5=mid; 1=too rough/too smooth); 
(c) is control (1=low; 5=high); 
(du) is duration (1= brief; 5=long).

Obviously, this is silly. Firstly, it's not entirely clear how you are supposed to measure these things. Secondly, they're combined in ways that make absolutely no sense. Thirdly, the thing is just full of mathematical symbols that bear precisely no relation to whatever they're supposed to mean.

I'm perfectly willing to believe that most of these factors affect how pleasant it is to shake hands with someone, but writing down a string of symbols in no particular order doesn't help to illustrate this at all. It just helps to generate publicity for the company that commissioned the result (whose name I won't mention, just because I'm petty like that). There are a few problems with the definitions - what is the value of (d) if you fail to smile at all? is (t) entirely symmetric about mid? What exactly is "mid" anyway? Surely we have perfectly good units to measure temperature in already? Is it really a good thing to maximise (du)? Like... would a 1000 year handshake be better than a 5 second one?

But that's not the main thing that grates with this particular story - it's the fake 'mathsiness' of the formula.

Forget the fact that it would be much easier to renormalise the arbitrary scales we were using to avoid having to square everything before we enter it into the formula. Forget the fact that we don't even know what PH is supposed to be - is it a property we want to maximise? Something we want to get as close to 100 as possible?

Why is there square root sign around the whole thing? It may be a while since I did anything with numbers, but I'm pretty sure that the square root function is monotone. That is, if we're going to be maximising this quantity, it makes *absolutely no difference* if we take the square root first or not. But even that's not the most annoying bit, that has to be:

What on Earth is that supposed to mean? And where the Hell did pi come from? One of the articles suggested that you could now optimise your handshake... if you have a maths degree. I assume this was supposed to be a joke, but I have two maths degrees, and am most of the way through a third, and I have no idea what 4<s> 2 is supposed to mean. Sure, it looks like maths, but then so does 4x6^2y+*7 if you don't know what you're talking about.

Now, I'm fully aware that these formulae aren't suppose to make sense, but they're still irritating. I mean, how hard would it be to write down something that was at least *meaningful*, if not actually sensible (well-researched is obviously too much to hope for).

1 comment:

magicicada said...

I have three things to say.
First, you are clearly not yet enraged enough about this.

Second, if the whole thing weren't quite so ridiculous, it might not be totally useless to have the square root. If this expression is just meant to indicate the goodness of the handshake, then we might want to use it as a term in some other expression. Like, maybe we have some total resource or effort, and are maximizing under this constraint. I am pretty sure that I can imagine a difference in those circumstances between wanting to maximize
something that is rooted vs something linear vs something exponential.

Finally, my handshake has been characterized as "too manly". I demand an explanation of how this could possibly fit into this expression.