Hello everyone and welcome to the Mindscape Podcast. I'm your host Sean Carroll and I wanted to start today's episode with a story.

I was on the internet and I noticed on Twitter a link to a very interesting paper in nature.

It was sort of a psychology study but an interdisciplinary group of people carrying it out.

And the study was basically the following. They would give subjects a little grid on a computer where there were some blank spaces and some colored in spaces.

And they asked the subjects to alter the pattern of squares to make the image they were looking at symmetric in some well-defined way.

So you could either add more squares to the image to make it look symmetric or you could remove squares.

You could click on squares and have them disappear to make it look symmetric.

And the human brain says the study has this feature that it is much more eager to add extra squares to remove them.

This turns out to be a more general feature the authors claim that if we have some design problem or some puzzle in front of us, we instantly move to adding stuff.

Subtractive change taking things away is a little bit more alien to us. And so you can think about why that is the neuroscience of that, the evolution of why we evolved that way and so forth.

So I thought that would be a fun topic for the Mindscape podcast a little bit different but interdisciplinary and interesting.

So the lead author of the leader of the lab that performed the study was Lidy Klotz looked him up on Google right into my dismay when you type in Lidy Klotz into Google.

What appears is the name of a professional soccer player not a professor of engineering at the University of Virginia.

I'm like, ah, that's not what I'm looking for. And then I realized further googling it is the same guy Lidy Klotz was a professional soccer player.

He later got his PhD in architectural engineering and is now a professor at the University of Virginia and carries out these really interesting interdisciplinary studies involving neuroscientists and psychologists, design people and engineering people.

So he agreed to come on the podcast and we had a lot of fun in this episode. And one of the reasons why it's fun is there are, like I said, these questions of cognitive neuroscience evolutionary biology.

Why did we evolve this way? There's also questions of engineering and design, right?

Given this tendency of human beings to like to add things rather than to subtract, does that offer us new hints to maybe improve our design principles by looking a little bit more at subtracting things.

And finally, it's almost a self-help self-improvement kind of thing. You know, can you get through your life better if you take more seriously the option of getting rid of things?

I know that Marie Kondo already patented this idea and Lidy brings her up. But what is the science behind that? You know, why do we feel happier getting rid of things rather than our usual tendency, which is to just add them on?

Lidy does have a recent book on this called Subtract, the Untapped Science of Less, where you can learn about both the neuroscience of psychology and what it means for design, engineering, and our everyday lives.

So, fun conversation, both serious, but also fun in the sense of ranging over a lot of different cool ideas. With that, let's go.

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