This is Hidden Brain. I'm Shankar Vedant.

In 1863, a terrible plague descended on the famed vineyards of France.

Tiny sap-sucking insects attack the roots and leaves of grapevines.

The pests destroy thousands of acres.

What turned a problem into a calamity

was that French vineyards were mainly planted with a monoculture,

a single species of grape

that had little natural resistance to the insect hordes.

It turns out that there are other kinds of species, for example, in the U.S.

that were not so affected that developed natural resistance to that pest.

But that was not the case of the French vineyard.

This is researcher Jordi Kwaabha.

He said the destruction continued for years and threatened the very existence of the French wine industry.

Eventually, though, French winemakers found a solution, adding diversity to the grapevines

onto cultivation.

They started grafting their native vines onto American plants, which had evolved to resist the insects.

By increasing the biological variety of the plants, the French wine industry rose again.

To me, the takeaway of this story is that by introducing more diversity, you're actually

making your environment more resilient and more likely to succeed in the long run. Today, we extend this idea from ecology to the world of psychology.

Specifically, we examine the effects of having a variety of emotions in our daily lives.

This episode is part of our Emotions 2.0 series.

We've previously explored the power of collective emotions,

...