Normally faceless storm troopers, being nice to Ewoks. Image by Stéfan
In short, because we’re connected. Because we live together. Because we need each others help. There are a few studies detailing why we’re altruistic, but few explaining how. To that I would posit, because we have an identity and a face.
For example, we went to this alley bar in Mount Lavinia that actually serves a decent lunch. On the way out our car was boxed in by two guys. This would often be a problem, but this time it wasn’t. Everyone had noticed that we were going out, I had casually smiled at the dudes that made eye contact, and the attentive staff transmitted the scene back into the bar. The van driver moved his car, creating a hole. One guy who technically didn’t have to move his car did, simply because it made my life easier. The owner came out and said he was sorry. People were so nice that it left me confused. Why?
Essentially, it’s that every social encounter between two people involves a guess about whether or not you’ll meet again in the future; you have to decide whether or not an interaction will be “one-shot” or “repeated.” By modeling “one-shot discrimination” in a computer, the group has shown that it makes more sense to presume that you’ll meet again down the road.
OK, so that’s a why. We’ve been to that bar before and I’m pretty sure we’re the only people that go there to eat. We’ll probably go again. Colombo is a small town and we could easily run into any of the patrons. But how? I can tell you one way I could have made that situation much much worse. Get in the car and honk. So the how makes a difference.
I think that difference was that I didn’t get in the car. That I communicated non-verbally but getting up and walking, and that by simply not being a dick in general, the staff and patrons were willing to help. The abstract need for help is the same, but the how is very very different.
Based on what I’ve read, there is a mathematical reason for people to be altruistic within families – you simply have a shared pool of genes worth preserving. This is called kin selection. The paper I cite above shows a mathematical reason for non-related people, the simple probability that you might meet again. So I consider the why relatively settled.
How are people nice? Broadly, I think people are nice to your face. Then they are nice to your identity. More rarely, they are nice to you anonymously, or without normal social feedback. By showing my face and not getting into my car, I kept things on that human level. At that level, years of evolution going back to primate and mammal sociability come into play. It’s physically hard to be rude to a flesh and blood human being, at a neurological level. We are simply too sensitive to the human form, down to specific brain circuitry for facial and emotional recognition.
The system breaks down most obviously when you get into a car, where you have no discernable identity. People are dicks, myself included. As a completely non-scientific example, I was driving down Baseline and I noticed that this guy in a Prado was being a total douche. I then passed Aravinda de Silva in his Ferrari (a much better car) and he was a perfect gentlemen. Perhaps because everyone knows he’s Aravinda (heroic cricketer) and he has an accountable identity on the road.
When people have an identity they have continuity from situation to situation. Hence, the why people are nice (might see them again) comes into play. Hence, walking is less hostile than driving, Facebook users are more trusting than other Internet users and non-Internet users at large, etc.
So, in sum, why are people nice? Because they might see each other again. How are people nice? By noting your face or identity such that they can recognize you and collect (or apologize) later.