As Danescu-Niculescu-Mizil points out, we’ve had thousands of years to hone our person-to-person interactions, but only 20 years of social media. “Offline, we have all these cues from facial expressions to body language to pitch… whereas online we discuss things only through text. I think we shouldn’t be surprised that we’re having so much difficulty in finding the right way to discuss and cooperate online.”

After collecting data, including from people who had engaged in trolling behaviour in the past, Danescu-Niculescu-Mizil built an algorithm that predicts with 80 per cent accuracy when someone is about to become abusive online. This provides an opportunity to, for example, introduce a delay in how fast they can post their response. If people have to think twice before they write something, that improves the context of the exchange for everyone: you’re less likely to witness people misbehaving, and so less likely to misbehave yourself.

Danescu-Niculescu-Mizil has been investigating the comments sections below online articles. He identifies two main triggers for trolling: the context of the exchange – how other users are behaving – and your mood. “If you’re having a bad day, or if it happens to be Monday, for example, you’re much more likely to troll in the same situation,” he says. “You’re nicer on a Saturday morning.”

Another way of addressing the low reputational cost for bad behaviour online is to engineer in some form of social punishment. One game company, League of Legends, did that by introducing a “Tribunal” feature, in which negative play is punished by other players. The company reported that 280,000 players were “reformed” in one year, meaning that after being punished by the Tribunal they had changed their behaviour and then achieved a positive standing in the community. Developers could also build in social rewards for good behaviour, encouraging more cooperative elements that help build relationships.

Much antisocial behaviour online stems from the anonymity of internet interactions – the reputational costs of being mean are much lower than offline. Here, bots may also offer a solution. One experiment found that the level of racist abuse tweeted at black users could be dramatically slashed by using bot accounts with white profile images to respond to racist tweeters. A typical bot response to a racist tweet would be: “Hey man, just remember that there are real people who are hurt when you harass them with that kind of language.” Simply cultivating a little empathy in such tweeters reduced their racist tweets almost to zero for weeks afterwards.

His team is not interested in inventing super-smart AI to replace human cognition. Instead, the plan is to infiltrate a population of smart humans with dumb-bots to help the humans help themselves.

Christakis turned this around simply by giving each person a little bit of control over who they were connected to after each round. “They had to make two decisions: am I kind to my neighbours or am I not; and do I stick with this neighbour or do I not.” The only thing each player knew about their neighbours was whether each had cooperated or defected in the round before. “What we were able to show is that people cut ties to defectors and form ties to cooperators, and the network rewired itself and converted itself into a diamond-like structure instead of a graphite-like structure.” In other words, a cooperative prosocial structure instead of an uncooperative structure.

Christakis has designed software to explore this by creating temporary artificial societies online. “We drop people in and then we let them interact with each other and see how they play a public goods game, for example, to assess how kind they are to other people.” Then he manipulates the network. “By engineering their interactions one way, I can make them really sweet to each other, work well together, and they are healthy and happy and they cooperate. Or you take the same people and connect them a different way and they’re mean jerks to each other and they don’t cooperate and they don’t share information and they are not kind to each other.”

“If you take carbon atoms and you assemble them one way, they become graphite, which is soft and dark. Take the same carbon atoms and assemble them a different way, and it becomes diamond, which is hard and clear. These properties of hardness and clearness aren’t properties of the carbon atoms – they’re properties of the collection of carbon atoms and depend on how you connect the carbon atoms to each other,” he says. “And it’s the same with human groups.”

Someone who’s thought a great deal about the design of our interactions in social networks is Nicholas Christakis, director of Yale’s Human Nature Lab, located just a few more snowy blocks away. His team studies how our position in a social network influences our behaviour, and even how certain influential individuals can dramatically alter the culture of a whole network.

This is compounded by the feedback people get on social media, in the form of likes and retweets and so on. “Our hypothesis is that the design of these platforms could make expressing outrage into a habit, and a habit is something that’s done without regard to its consequences – it’s insensitive to what happens next, it’s just a blind response to a stimulus,” Crockett explains.

“Content that triggers outrage and that expresses outrage is much more likely to be shared,” Crockett says. What we’ve created online is “an ecosystem that selects for the most outrageous content, paired with a platform where it’s easier than ever before to express outrage”.

I trudge a couple of blocks through driving snow to find Molly Crockett’s Psychology Lab, where researchers are investigating moral decision-making in society. One area they focus on is how social emotions are transformed online, in particular moral outrage. Brain-imaging studies show that when people act on their moral outrage, their brain’s reward centre is activated – they feel good about it. This reinforces their behaviour, so they are more likely to intervene in a similar way again. So, if they see somebody acting in a way that violates a social norm, by allowing their dog to foul a playground, for instance, and they publicly confront the perpetrator about it, they feel good afterwards. And while challenging a violator of your community’s social norms has its risks – you may get attacked – it also boosts your reputation.

“There is a lot of evidence that cooperation is a central feature of human evolution,” says Rand. Individuals benefit, and are more likely to survive, by cooperating with the group. And being allowed to stay in the group and benefit from it is reliant on our reputation for behaving cooperatively.

Over the years, scientists have proposed various theories about why humans cooperate so well that we form strong societies. The evolutionary roots of our general niceness, most researchers now believe, can be found in the individual survival advantage humans experience when we cooperate as a group. I’ve come to New Haven, Connecticut, in a snowy February, to visit a cluster of labs where researchers are using experiments to explore further our extraordinary impulse to be nice to others even at our own expense.