This is Hidden Brain, I'm Shankar Vedantan.

Earlier this month, a man named Brian Chesky sent out an email that began like this.

At the heart of our mission, he wrote, is the idea that people are fundamentally good

and every community is a place where you can belong.

Chesky is the CEO and co-founder of Airbnb, the online marketplace that connects travelers

with people looking to rent their homes.

Chesky's email sent to users across the globe was a response to concerns about racial bias.

Some guests say they've experienced prejudice while trying to book rooms on Airbnb.

We first explored these complaints in the spring in an episode titled Airbnb Wild Black.

The host would always come up with excuses like, oh, someone actually just booked it.

I got suspicious when I would check back like days later and see that those dates are still available.

Today we're going to bring you that episode again with a few updates to reflect changes

the company says it's making.

We'll begin not with Airbnb, but with another online platform you may have heard of, Facebook.

So a few months back, I was on Facebook when a friend request came in.

I don't have a great memory for faces and names, so I found myself trying to figure out

if I had met this person somewhere.

But then at the back of my mind I remembered a study.

It set my friendship choices on Facebook might be shaped by biases outside of my conscious

awareness.

Michelle Hebel is a psychologist at Rice University who ran the Facebook study.

She designed fictitious Facebook profiles for two men and two women.

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