Today's episode of Rationally Speaking is sponsored by Givewell, a nonprofit dedicated to finding outstanding charities and publishing their full analysis to help donors decide where to give. They do rigorous research to quantify how much good a given charity does, how many lives does it save, or how much does it reduce poverty per dollar donated? You can read all about their research or just check out their short list

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It's free and available to everyone online. Check them out at give well.org. Welcome to Rationally Speaking, the podcast where we explore the borderlands between reason and nonsense.

I'm your host, Julia Galeff, and my guest today is Stuart Ritchie.

Stuart is an expert on human

intelligence and cognitive aging, and maybe to introduce him, the best thing is just to read

you his Twitter bio. Stuart is a postdoctoral fellow at the psychology department of the

University of Edinburgh, and looks like a cartoonish, startled hedgehog. Stuart, welcome to the show.

Hi, how's it going?

I just have to tell you that what I love about your Twitter, I mean, I love your Twitter

presence overall.

Oh, thank you.

But one particular thing that I love is how the photo of you, in the photo that you posted

on Twitter, you're sort of staring horrifiedly down at the lower right-hand corner of your screen, which makes it look, with every tweet you posted, it makes it look like you're horrified by what you've just written because you're staring at it in dismay.

Yeah, well, it is often something, you know, annoying or depressing that I'm putting up there.

You know, someone misinterpreted a paper or there's a rubbish scientific paper or some, something like that.

And you're like covering half your face almost in a, oh God, expression.

Yeah, I also like, I couldn't bear to put up a serious picture because I just can't,

I just can't bear the thought of posing for a serious picture and putting it online.

So that one seems to work.

So you definitely avoided that failure mode, I'll say.

So, oh, I should also add that Stewart recently published a great book with a somewhat

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