Lulu Miller

But Daniel's basically like, a mother's voice is one of the first voices that you hear in your life.

And studies have shown that children are actually able to recognize their mother's voice before they're even born.

So like, in the womb, right around 18 weeks, ears...

poke out of the side of the head of a fetus.

And researchers have done studies showing that when the fetus hears the voice of the person who's carrying it, its heart rate starts going way faster.

And it's kind of inferred that the fetus can recognize what we're calling mother's voice from other voices.

What is the beating heart?

Sorry, go ahead.

Oh, sorry.

Why would a heart beat faster?

You know, I mean, I guess it's... Anxiety.

Yeah, truly anxiety.

The truth is that no one really knows because it's a fetus.

But it was clear to Daniel that this mother's voice was powerful.

And so what Daniel wanted to know is, okay, what is this powerful voice actually doing in, say, the brain of a kid?

So at this point, Daniel's at Stanford.

And basically what he and his team do is they get these kids.

Kids at a range of ages between 7 and 12.

And then they have the mothers of these children come in.

For voice recording.