Pushkin.

In southeastern Brazil, there are two small fishing communities living just 40 miles apart.

The two villages are similar in lots of ways, but they do have one important difference.

One community lives on the ocean, while the other lives by a lake.

About a decade ago, a young economist visited the lake settlement and found it a trash-strewn and unwelcoming place.

But traveling downstream to the sea, he was astounded by the friendly greeting he received

in the ocean side community.

Intrigued, he decided to properly study how trusting both sets of fishermen were.

At the start of their careers, they all shared similar outlooks.

But those who spent years fishing on the lake grew less trusting and more selfish.

And those who spent time working on the ocean grew more generous and trusting.

What could explain these differences?

The sea air, pollution in the lake, the different nutrients in the fish they caught.

I'm Jamil Zaki and in my book Hope for Synics, the surprising science of human goodness,

I wrote about this research. The reason that one fishing village seemed mean,

and the other more kindly was to do with the type of fishing its inhabitants undertook.

Fishing out on the high sea requires boats with heavy equipment, ones that no one can operate alone.

Survival on the ocean requires working with others. But fishermen on a calm lake use smaller boats, ones that wind up competing for the best spots.

Lake fishing thus becomes a lonelier, more cutthroat way at life.

Which fishing village would you want to live in?

Most of us would prefer the sea. We find comfort in

trusting others and joy and meaning in connecting with them. But sadly a lot of us

...