The science of first impressions is complicated, influenced by things outside of our control, neurological processes that we don’t understand and inaccurate stereotypes.

It takes less than a second to form an assessment of someone’s face. These first impressions predict all kinds of important characteristics, not just attractiveness. These impressions we make in a second tend to be shared by the majority of the people. But that doesn’t necessarily make them correct.

“A first impression could be misleading,” says professor Alexander Todorov, author of the book Face Value: The Irresistible Influence of First Impressions and a professor at Princeton University. “Trying to figure out what a person is like from a simple exposure is basically ridiculous. We only make first impressions about strangers. So naturally they are superficial.”

Whether our predictions are accurate or not, we make them quickly and we stick to them. Even if we are given more time than a second to judge the attractiveness of a face, we are unlikely to arrive at a different conclusion. According to professor Todorov, there are three universal qualities that people infer from a face: attractiveness, trustworthiness and dominance.

In these first impressions, men and women are not judged equally. Women who appear masculine are evaluated negatively whereas men would be evaluated positively. This applies to both genders, so men and women [both] make negative assessments of masculine-looking women.”

First impressions of faces are superficial, general and can be inaccurate. If we think about this in the context of dating apps, we also have to think about the effects of how a photo is taken. The photos we choose to publish on dating profiles are those that present ourselves in the best light. Not just chosen for attractiveness, they are also there to reflect personality and social cues, like adventurousness or generosity.

First impressions are rapid but shallow and can change over time if you have better information, like when your date starts speaking. “The only way to tell whether two people will really like each other is when they have to talk. People don’t make good predictions for compatibility without talking,” says professor Todorov.

Professor Todorov  has categorised all the conversational strategies we use which should lead to a second date and he came to several conclusions: “The traditional dating habit was that men approach women and we have found that it is men who approach women when dating online, too,” says professor Todorov. “But the most interesting part is how few gender differences there were in the types of strategy used.”

Men and women are more similar than they are different. Being sincere about the type of person you are looking for is more effective than talking about your wealth, profession or whether you are looking for love.

“Something that is unique about online dating is that you have a longer time to figure out if your date is going to meet your expectations,” says Todorov. “Sometimes with online dating you have a tendency to build people up in your head which can lead to disappointment. We can idealise people when we don’t have a lot of information to go on.”

Having said that, there have been several marriages from these speed-dating meetings, so there must be some logic in there, says Todorov: “Some people now have children, so it produced some nice results”.