I may be making that up, but I'm pretty sure it's got a germ of truth to it.

I'm Angela Duckworth.

I'm Stephen Dubner.

And you're listening to No Stupid Questions.

Today on the show, what sort of incentives increase vaccination take up?

If they're willing to enter me in a lottery that might pay me a million dollars, it must be

really bad.

Also, would you rather have the power of flight or invisibility?

This is a hypothetical question that you can never actually execute.

I did order an invisibility cloak just the other day from the back of the matchbook.

So, Angela, the behavior change consortium that you help lead, behavior change for good, recently did a big study, trying to figure out how to get more people to get vaccines.

Now, this was in anticipation of a COVID-19 vaccine. So the actual

experiment was encouraging people to get the flu vaccine, not the COVID vaccine, which wasn't ready

yet. As I've read, the research found that most efforts didn't work that well. But there was one that

was really successful, which was when people got a text

saying that a vaccine dose is reserved for you or waiting for you. Do I have that right so far?

You have it mostly right. It's not that most things didn't do so well. These things actually,

as a group, worked really well, but you're right that there was a particular kind of message that performed better than the rest.

So these are essentially piggyback messages. These are people who are already going to a doctor and you're saying while you're there you should consider getting the vaccine. Is that right?

Correct.

So I did say that one of the worst performing nudges was a joke. Correct me if I'm wrong,

but here's what I'm reading from the article. A dog tells a joke to a cat. Did you hear the joke

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