Electoral magnetism

It's great being a physicist: we are equipped to explain everything. For any problem - traffic jams, economic meltdown, why cornflakes get stuck in the box – a physicist can pull out a set of equations that offer a solution. And there's no problem so enticing as a general election.

Physicists aren't fooled by the naive notion that voters are drawn to policies. They use the science of "clustering" to debunk this. Clustering determines things such as the arrangement of salt crystals on your brow when sweat evaporates. The crystals cluster around a "seed", whose characteristics cause other salt crystals to form and attach themselves to it.

Swap clusters for policies (or candidates) and you have what seems like the perfect model for democracy: attractive policies or candidates will draw clusters of votes. However, a group of German physicists analysed the votes obtained by candidates in council elections and found that
it doesn't work like that.

When they plotted the election information on a graph, they obtained a number, known as an exponent, from the graph's slope. The exponent is characteristic of the process. For crystal clustering, it has the value of two. But election models give an exponent of minus one. There's no match.
The only physical phenomenon that matched election data is magnetism; it arises from the way iron atoms orient themselves within metal. A magnet is strongest when the atoms are all facing the same way, but this alignment is never perfect.

Plot a graph of the number of atoms facing each of the possible directions in a magnet and you'll find it has an exponent of minus one: a perfect match for the council election data.

It sounds like a triumph, but it's quite depressing. Magnetisation happens when an atom within the magnet finds itself surrounded by neighbours that are facing in a particular direction. Their electrical push and pull will cause that atom to align itself with the rest. As more atoms turn, the alignment gradually spreads through the metal until it reaches a stable equilibrium.

People, like atoms, align themselves with those with whom they have direct contact (summed up by Homer Simpson: "I'm not popular enough to be different").

When, like me, you're fighting an election campaign on high-minded policies and no budget, the last thing you want to hear is that you've got to have widespread support before you can gain widespread support. Luckily, I'm a physicist. And that means I'm confident I can find a whole other set of equations to support my campaign. First, let's assume the voters are perfectly spherical . . .

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 03 May 2010 issue of the New Statesman, Danger