From the brains behind brains on, this is the moment of um.

Um, um, um, um, um, um, um.

Moment of Um comes to you from APM studios. I'm Rosie DuPont.

Um.

A mosquito bites you.

Your grandma knits you a scratchy blanket.

Your friend tickles you with a feathery cat toy.

You're posing for a family portrait and you're not supposed to move,

but you have an itch on your ankle that you absolutely have to do something about.

What do all these scenarios have in common?

They're itchy. Listener Samantha was wondering why we itch. And someone better tell me soon because all these tickly situations are

driving me bananas. What makes us itch? I've always wondered the same thing and that's why I decided

to study it. Hi, my name is Sonali, Molly, and I study why we itch and what makes us itch and why sometimes

an itch doesn't stop.

The kinds of things that can cause itch can be chemicals that might be coming from plants and

insects.

They can also be chemicals that are released by our immune cells to tell us

to experience itch, or they can be something like a light touch or an itchy sweater. Itching is

useful because our sensation of itch serves as this really important warning system for us. And it

tells our brain, okay, look, there's something here that we don't

want here. And so we're going to do a behavior, in this case scratching, in order to remove it,

and draw attention to it and be able to detect things that you might not even see or hear,

...