A recent Danish study used machine learning to predict the political bias of 3323 people, based only on analysis of their faces. Its accuracy was 61% – a good amount better than chance. What's more, it found that good-looking faces were more likely to belong to right-wing candidates, adding to an increasingly substantial literature that finds conservative people more attractive.

Here's a quick summary of that research.

• In Europe, the US, and Australia, right-wing politicians are more attractive than their left-wing counterparts
• Men with high upper-body strength are less likely to support forced redistribution of resources
• In the US, elected female Republicans have more feminine faces than elected female Democrats
• Even controlling for socioeconomic status, more attractive people are more likely to identify as conservative

There are a few plausible mechanisms for these findings. Being attractive confers a number of advantages on people – known as the 'halo effect' – such as being considered more competent, and a better person, by those around them.

In turn, being treated in positive ways by others makes us more likely to internalise those characteristics. In other words, treating someone as if they were generous and competent has a good chance of turning them into someone who really is generous and competent. We've previously written about how this works in romantic relationships: treating your partner as an ideal version of themselves helps them become more like that ideal. This process eventually becomes self-reinforcing and creates a virtuous circle of self-improvement.

Being treated well by others can change our attitude to the world, making us more likely to believe that systems are generally fair, and more likely to feel in control of our lives and our futures. All these views are associated with increases in happiness – and also with conservatism. (It's worth noting that conservatives are happier overall than left-wingers.)

Attractive people are also more likely to be invited to things, both formally and informally, and to participate in community groups. Conservative thought often emphasises the importance of institutions and organised communities, such as religious and educational associations, and people with strong community ties are more likely to be invested in the continuation of those communities. Finally, attractive people are likely to outearn their unattractive peers, and earning more is associated with less desire for the state to redistribute wealth.

What does this mean for dating and romance? Some sources report that at least in the US, "mixed" marriages (between Democrats and Republicans) are increasingly rare, although more common amongst college graduates. Many Swan members also express preferences about dating across political lines: as a general rule, left-wingers are less willing to date right-wingers than vice versa, although plenty of exceptions exist on both sides.

When it comes to serious relationships, it seems that right-wingers have the upper hand once more. American Republicans are typically in more committed and happier relationships than their Democrat peers, particularly when paired with other Republicans.

One of the contributing factors here is likely to be that those on the right typically have smaller (though not necessarily less intense) circles of moral concern, meaning they're likely to prioritise those closest to them and with whom they have lots in common – as opposed to, say, people from other backgrounds or regions. Family and local community take precedence over solidarity with strangers, even if those strangers are uniquely in need of care.

So: right-wingers are likely to be happier, richer, and more attractive. But for the sake of balance... they're also likely to have a smaller circle of moral concern, be lower in empathy, and have lower cognitive and emotional intelligence. Political divides might be neat, but human behaviour seldom is.

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