The Metropolis blog

If you ask people what makes a face attractive, many will say it's symmetry , because apparently that shows whether the person is healthy, i.e. free of parasites and genetic defects. But it turns out the common wisdom is wrong. Sure, gross asymmetry — what we'd consider a deformity — is unattractive. But in wealthy countries that level of asymmetry is extremely rare, since most cases are corrected with cosmetic surgery at a young age. So, what makes people think that symmetry is attractive? Well, decades ago, some researchers took pictures of female faces, cut them down the middle, and mirrored both the left and right sides. This produced two perfectly symmetrical versions of each face. What they found was that for most of the faces, a symmetric version was a bit more attractive than the original. Not always, but more often that you'd expect by chance. So, on average , the symmetric faces were a bit more attractive. And this study got a lot of publicity. But the effect ...

Should apps give you dating advice? It's something we've though about at Metropolis. The app Coffee Meets Bagel , for example, gives you profile prompts and icebreaker questions. Hinge has canned prompts that help you reveal your personality and sense of humour. But is this a good idea? We think not. An "historical" precedent You may be familiar with the story of Cyrano de Bergerac, popularized by the movies Roxanne (with Steve Martin and Daryl Hannah) and Cyrano de Bergerac (with Gerard Depardieu). Cyrano is a charming and intelligent nobleman with a big nose. He's in love with the beautiful Roxanne, but doesn't have the courage to ask her out because of his looks. Christian, on the other hand, is good looking but dumb, and also fancies Roxanne. Cyrano is persuaded to write letters to Roxanne on Christian's behalf, and because of the letters she falls in love with Christian. Clearly this isn't going to end well. **Spoiler alert** It doesn't end...

What makes us sexually attracted to another person? The not-so-romantic answer is that it's the limbic system of our brains — the hypothalamus and amygdala — that calls the shots. This part of our brain is commonly — if inaccurately — known as the lizard brain , and lights up when we meet someone we find sexually desirable. However, our lizard brains have two inconvenient drawbacks. They doesn't listen First, our lizard brains don't pay attention to our conscious minds. The heart wants what the heart wants , and our conscious minds don't get a say in the matter. For example, consider a religious conservative who is born gay but believes that homosexuality is a sin that will send them to hell. They will desperately want to be straight. And a pedophile will surely know that acting on their desires will get them arrested. But their lizard brains don't care. They want what they want, and won't be told otherwise, consequences be damned. They don't explain their a...

Speed dating is one of the best ways to research human attraction, because it's based on revealed preferences rather than surveys, and everyone has a strong incentive to give truthful answers. If you'd like to do your own analysis of speed dating data, there's a freely-available  spreadsheet  from a Columbia University study, with the results of over 4000 dates. The dates occurred at events with (typically) 10 male and 10 female participants, who "dated" everyone of the opposite sex in quick succession. As well as the outcomes of the dates, the spreadsheet contains (somewhat patchy) demographic data, such as the age, undergraduate major, race, and some personality attributes of the participants. For an in-depth analysis of the data, have a look at this Kaggle notebook . A simple analysis There are lots of ways to analyze the data, but a simple hypothesis to test is: given the results of previous dates, can you predict how people will decide on the next date? So, a...

Researchers hate relying on surveys. They assume that people will lie, give the socially acceptable answer, or, in the case of hypothetical questions, just make something up. So researchers prefer to rely on  revealed preferences , i.e. what people actually  do rather than what they say . Some of this data can be found in historical records, but occasionally researchers get to run actual experiments. And when it comes to human attraction, their preferred experiment is  speed dating , where a bunch of men and women chat to each other for a few minutes, mark their card yes or no , then move on to the next person. Looks matter In the paper  HurryDate: Mate preferences in action  researchers analysed the results of commercial speed dating events and found that Men were attracted to women based on weight and age. Women were attracted to men based on looks, height, and age. They also found that men who were in good shape with a high income were the pickiest, while t...

You may have noticed that some women are more popular than others. Way more popular. Demand for them greatly exceeds their supply. Fortunately homo sapiens  has evolved a way to resolve this imbalance without men evolving antlers and headbutting each other to compete for their affections. It's the fear of rejection . Feedback is a gift Social rejection hurts. It activates the same part of the brain as physical pain, and our brain learns to avoid things that hurt. This avoidance manifests itself as fear, ranging from unease to full-on terror. The result is that, in real life, most men will only approach women that they both find attractive and  who aren't likely to reject them. They won't approach women who are too  attractive because they are, literally, scared of them. This works well from a woman's perspective. She's only approached by a handful of men, most of whom have a chance of being suitable. (OK, some of the men are really drunk, and others are working fro...

Historically, economists have assumed that giving consumers more choice is a good thing. With more options, the thinking goes, consumers are more likely to find something that makes them happy. Which improves the chances they'll make a purchase. At least, that was the theory. The Jam Study In 2000, psychologists Sheena Iyengar and Mark Lepper ran an experiment. They set out a display table in a food market with 24 varieties of gourmet jam and counted how many people sampled the jam, and how many made a purchase. And on another day they did the same thing, but with only six varieties of jam. As expected, the table with 24 jams was more popular with passers-by, with more people trying samples. But when it came to actually making a purchase, people were ten times more likely to buy from the six varieties than they were from the 24. That came as a huge surprise. Keep it simple There is still debate as to  why  people behaved the way they did. Some even argue that the whole study i...