Politics as Biology: Explaining the Razor Edge of Partisan Politics

Published by timdean on

Following Obama’s re-election, M.S. at The Economist ponders the startlingly improbable situation in the United States where such a strongly partisan country can keep rolling out elections that are knife edge finishes:

This is what strikes one most strongly looking back at America from across an ocean: the country seems repeatedly embroiled in savage 51-49 electoral campaigns, and it seems to be increasingly paralysed by irresolvable rancour between right and left.

And think about it for a second: this is bizarre. If Americans are in fact divided between two extremely different political ideologies, it would be an extraordinary coincidence if each of those philosophies were to hold the allegiance of nearly equal blocs of support. That situation ought not to be stable. Adherence to these two ideologies ought to shift enough just due to demographics that the 50-50 split should deteriorate. And yet the even split seems to be stable. What’s going on?

Good question. Here’s a speculative answer, using the tools of population biology as a lens to understand politics:

It starts by looking at political attitudes as a trait that varies across the population, then wondering how it is that variation in this trait is somehow maintained at an even 50/50 split.

In such a case, a 50/50 split that continues over time would be called a stable polymorphism – the paragon example being sex (i.e. sex ratio). The reason we have 50/50 men/women is that the fitness of individuals of each sex increases as their frequency in the population decreases, until an equilibrium is foundat 50/50 (actually more like 1.06 males for ever female for other interesting reasons).To make this work for politics, we need to cash out what we mean by trait and fitness in a way that makes sense in this context.

In this case trait could be “ideological leaning” towards a cluster of attitudes or worldviews. Some might be moderate, and some might be outliers (extremists). This trait is continuous rather than discreet, like height rather than sex. But continuous traits can exhibit stable polymorphisms too.

In this model, fitness would be cashed out as the extent to which an individual is heard by and influences others. Individuals with higher fitness are more vocal and politically active.

To maintain the polymorphism, it would have to be the case that fitness increases as frequency in the population decreases (like sex). So if there are more liberals in a population, then the conservatives (particularly the outliers on the distribution) become more active and more vocal. They then persuade others and recruit them to their cause (a form of cultural reproduction of a trait).

However, as they gain the majority, their fitness decreases (complacency) and the liberals’ fitness increases (they get fired up).

Exhibit A: the Tea Party following Obama’s election in 2008.Now, in biological terms, what has happened in America over the past few decades has been a stretching of the distribution, creating more outliers and flattening the middle.

In political terms, I’d say that process probably started in the 1960s with a lean to the left. Then a pull to the right in the 1980s. Then back to the left in the mid-1990s. Then a sharp tug to the right in the 2000s, followed by a counter-tug to the left in 2008. Finally, a lunge to the right by the Tea Party. Overall, the equilibrium point has drifted right, but equilibrium has been roughly maintained, and the distribution has ended up stretched from where it was in the 1960s.

I’d also add that the media play a role in this cultural evolutionary model. The media is the one of the primary mechanisms by which the agitated get heard. The prevalence of ‘he said, she said’ reporting has allowed the more vocal agitators to be heard, and influence, others. A lack of scrutiny or deep analysis of the issues (or a corresponding disengagement by the electorate in facts) has let ideology dictate the agenda, enabled by a false understanding of ‘balance’ by the media.

Now, if this was biology, you might expect a speciation event is imminent, as the two bulges on each side refuse to interbreed and drift further apart in terms of their traits. Heck, maybe that’s already happened…

1 Comment

Paul · 2nd December 2012 at 4:49 am

I like the idea, but how would your theory account for the split between Red counties and Blue counties? That is to say, on a national level, it seems like your explanation would work, but on a local level, many, if not most places in the U.S. vote overwhelmingly for one party or the other. Why wouldn’t there be an equilibrium in places like the Northeast, where people unsatisfied with the status quo flock to the local Republican party as a way for their voices to be heard?

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