Empty heads, cognitive science has taught us, learn nothing. The powerful cultural and personal flexibility of our species is owed at least in part to our starting off so well-informed; we are good learners because we know what to pay attention to and what questions are the right ones to ask.

It has been a period where people have been far nicer to one another in every possible way. I'm not saying it's because we're dropping our empathy that we're nicer to each other, just that the drop doesn't seem to be causing any harm.

I think there's some evidence that we're empathic by nature. There is some evidence from studies of babies and young children that they resonate with the pain of others, and there's some work by Frans de Waal that other primates also resonate with the pain of others.

We are constituted so that simple acts of kindness, such as giving to charity or expressing gratitude, have a positive effect on our long-term moods. The key to the happy life, it seems, is the good life: a life with sustained relationships, challenging work, and connections to community.

If you like somebody, they look better to you. This is why spouses in happy marriages tend to think that their husband or wife looks much better than anyone else thinks that they do.

I think empathy can serve as a moral spark, motivating us to do good things. But anything can be a moral spark.

When people want to inspire you to turn against some group of people, they'll often use empathy. When Obama wanted to bomb Syria, he drew our attention to the victims of chemical warfare. And in both of the Iraq wars, politicians said, "Look at the horrific things that are happening." I'm not a pacifist. I think the suffering of innocent people can be a catalyst for moral action. But empathy puts too much weight on the scale in favor of war. Empathy can really lead to violence.