A Cup of Knowledge: With Guests A.J. Jacobs & Steven Sloman

Speaker 1: A lock on a door. How well would you say you understand how that works?

Speaker 2: I would say maybe like eight, nine out of 10. I mean a key and a lock, fairly straightforward, right? So my understanding is you have the key that has all those different bumps, and as you put it into the lock, there are pins in a barrel. And so as you put the key in, the pins go up and down and somehow, OK, I don't quite know how, but there's something that happens with the pins moving and then you turn the key. I think? At least I thought I did. Perhaps I don't understand as much as I thought I did. I guess I'll take my eight or nine down a few pegs to like three out of 10.

Speaker 3: Yeah. I feel like I have a pretty strong grasp of how a zipper works. Feels like a pretty simple mechanism.

Speaker 1: Can you put a number on it?

Speaker 3: Ooh, maybe like a nine out of 10. The way that a zipper works, how would I describe this? OK. There's two rows of teeth. They've got little notches on them, and then at the bottom there's like little stoppers and somewhere along the bottom you've got a tab attached to one side. Somewhere inside of that tab mechanism, there must be something that feeds them together, but I'm not entirely certain. Yeah, I don't really know how that part of it works, I guess. I guess I don't really understand it quite as well as I thought I did. Now I'm kind of embarrassed that I said nine out of 10 because I don't actually feel like it's a nine out of 10. Probably more like a four.

Katy Milkman: You just heard two perfectly smart people attempt to explain how a couple of seemingly simple mechanisms work. There's an interesting disconnect, isn't there? Between how well they think they understand how a lock or zipper works before they've actually talked it through, and how well they realize they understand it after they've had to explain it.

We're going to explore that imbalance in this episode and how it affects politics, relationships, and how we think of simple everyday things.

I'm Dr. Katy Milkman, and this is Choiceology, an original podcast from Charles Schwab. It's a show about the psychology and economics behind our decisions. We bring you true and surprising stories, and then we examine how these stories connect to the latest research in behavioral science. We do it all to help you make better judgements and avoid costly mistakes.

A.J. Jacobs: If my son had come and said, "How does coffee get made?" I would give him my view of the three or four steps that I thought it required. You grow the coffee, you ship it, then it goes to the coffee shop, they heat it up, and then they put water on it, and you've got coffee.

Katy Milkman: This is A.J.

A.J. Jacobs: I'm A.J. Jacobs. I am a writer. I live here in New York City. I work from home. And I live with my family, my wife and three sons and our dog and two tortoises.

Katy Milkman: A.J. is a journalist and author who immerses himself in his stories. In his book, Thanks a Thousand, he set out to understand the process that produces his morning cup of takeout coffee and to thank all the people involved. The idea started around the family dinner table.

A.J. Jacobs: It occurred to me that when I'm eating, I just don't give much thought to how many people it took to get that food onto my plate. I really took things for granted. So I thought it would be nice to start a little family ritual where before a meal we could say something like, "I'd like to thank the farmer for growing these tomatoes and the woman at the grocery store, the cashier, for checking them out." Just give a little more sense that these just didn't appear on our plates, that it took something to get there.

My son, who I think was 11 or 12 at the time, he said, "Dad, it's fine for you to thank these people, but it's also kind of lame because those people are not here. So, if you really want to commit, then you should go out and thank them in person." I think he was kind of just giving me sass. I don't think he expected me to take him up on it. But I'm a writer who specializes in doing these life experiments, and I thought this could make a very interesting book.

Katy Milkman: A.J. decided he would home in on one aspect of his morning meal.

A.J. Jacobs: My kids wanted me to focus on marshmallows or candy of some sort, but I went with my own addiction, which is coffee, to see how my coffee is actually made. I thought it would be a good amount of work, but relatively straightforward, relatively simple.

Katy Milkman: How complicated could it be? It was just a cup of coffee. As A.J. said at the beginning, someone grows the coffee, they ship it to your coffee shop, the barista brews it, and voila, you've got your morning brew. He set out to trace the path that his coffee takes to get to him starting in his local coffee shop. He assumed it would be simple.

A.J. Jacobs: So I started out with the barista who works at my local coffee shop, Joe Coffee, here on the Upper West Side of New York. I thanked her for my cup of coffee, and she thanked me for thanking her. I asked her who could she not do her job with, and she gave me a list of people, and part of it was the beans. Of course, you can't make coffee without the beans. One of the people that my barista led me to was this guy who buys the coffee. He goes around the world tasting coffee and saying, "These are the 30 that we should serve." And I said, "What happens before you get the coffee?" And he said, "Well, they have to be roasted."

Katy Milkman: Roasting coffee beans. You probably have a good idea of how that's done, or do you? Let's revisit one of the volunteers from our earlier survey.

Speaker 1: How well do you understand how coffee beans are roasted?

Speaker 2: 10 out of 10. Very simple, I think.

Speaker 1: OK, great. Can you explain it?

Speaker 2: You will dry them out in the sun or in some kind of facility, and then you roast them. Or, no, I guess you wouldn't dry them out if you roasted them, so you'd roast them in the oven and then they wouldn't need to be dried. OK.

Speaker 1: Can you tell me about the steps in roasting coffee beans?

Speaker 2: I believe it's a big oven, and you can have them twice roasted, three times roasted. I think that's a thing where you can have them multiple, although you don't want to burn them. I know it's important not to burn coffee beans because that can ruin the flavor. I think that's how it all goes together. But now I'm kind of second guessing anything I thought I knew about them.

Speaker 1: So now if you had to rank your understanding, what would you say?

Speaker 2: What did I say before? 10 out of 10?

Speaker 1: Yeah.

Speaker 2: I'm very skeptical of what I've told you now, so probably a five out of 10.

Katy Milkman: OK. Now back to A.J. and what he discovered about the process of roasting coffee beans.

A.J. Jacobs: The roastery was in this huge warehouse-type building, and, yeah, it was very loud and very hot.

These roasters, they're not small. They have a huge drum. It's the size of one of those inflatable pools that you put on your lawn for your kids. And the machines are enormous. They look like if a pizza oven and a clothes dryer had a baby, that's what it would look like. And there was so many gadgets. There was all of these electronic beeps, and they were keeping track of the moisture and the chemistry of the bean. It felt like a hospital room, in a sense: a very good smelling hospital room, because there were all these charts and graphs. He tried to explain to me, and I understood about 20% of it. You have to have rigorous training to become one of these roasters because it takes skill. It all depends on the temperature and the speed at which it achieves that temperature and eight other variables that I am forgetting or never knew.

Katy Milkman: Clearly, there's much more to the story of how coffee gets from the plantation to your cup. Another area where A.J. underestimated his own understanding was around the plastic lid that covers a takeout coffee cup.

A.J. Jacobs: I thought, "Well, there can't be much complexity in this." The coffee lid, how complex can that be? It's a piece of plastic. You put it over the cup. But I interviewed the man who designed the lid for the coffee cup that I use at my cafe, and he had me on the phone for two hours. He was so passionate he could have gone for like eight or ten hours. I couldn't believe the amount of thought, creativity even, and passion that went into this coffee lid. He argued it's a very important part of the whole coffee experience because smell is so important to your taste, and a bad coffee lid will block the smell. So he talked about designing the hole in the middle of the lid so that the smell can come out. He talked about making the recess for your nose even deeper so that you could get maximum odor. He talked about the way that the little tab went to make sure that the coffee came out in a smooth way as opposed to like a waterfall. You want it at a certain rate of coffee in your mouth per second.

Katy Milkman: Of course, coffee is a drink, and that means that water is an important ingredient.

A.J. Jacobs: So the guy who buys the coffee, the coffee expert, told me that coffee is mostly water. It's only 1.2% of the little powder from the coffee beans, and 98.8% is water.

Katy Milkman: But even here, A.J. thought he had a better understanding than he actually did.

A.J. Jacobs: I just turn on the tap, and I'm like, "Look at that. I got water."

And I knew vaguely that it was in a reservoir in upstate New York, and that some pipes went down, but I had no idea how complicated it is to get a glass of drinkable water. I went up to visit the reservoir in upstate New York, and I actually didn't know what to expect. I guess I just figured it's a reservoir. There are a couple of people. They turn a little wheel, and the water goes into the pipe and comes out my sink.

Katy Milkman: As you've probably guessed, the workings of a city water reservoir turned out to be much more complex than A.J. had thought.

A.J. Jacobs: I saw the hundreds of different types of people that you need. You need chemists who are testing the water. You need people who go out in February in the freezing and go out and get the samples so that they can be tested. There are park rangers who patrol and even pick up the deer poop so that it doesn't go in your water.

Katy Milkman: The line from his morning coffee to the source was getting longer and longer and more and more complicated. He reached out to the Minnesota miners who extract the iron that makes the steel used in coffee roasters. He reached out to the warehouse workers who stacked the bags of coffee beans, to a truck driver who delivered those beans to the roastery. He even reached out to Madison Avenue marketers who captured his wandering attention with coffee ads.

A.J. Jacobs: I could have done hundreds of stops. This was just the tip of the iceberg, but the final stop I made was going to the farmers who grow the beans. And it was a small family farm in Colombia, South America. I went there with a guy who works at Joe Coffee, and it was quite an adventure to get there. We had to drive along these cliffside roads and hairpin turns. We got to the family farm. It was eight brothers and one sister, and I explained to them that I am trying to trace the path of my coffee and thank everyone along the way. They were a little baffled at first.

Katy Milkman: Again, A.J. figured that he basically understood how coffee was farmed.

A.J. Jacobs: They put the seeds in, they put some manure on, it grows, they pick it, and they put it in a truck. As someone who grew up in a city and hasn't spent a lot of times on farms, I had an incredibly naive and simplistic view of how food is grown. I just had no idea the complexity of modern farming.

It's an incredibly complex thing to have a coffee farm. You have to have all sorts of equipment. Coffee beans don't grow on trees as beans. They are inside a little red fruit that looks like a cherry tomato. They're called coffee cherries. And so they pick the coffee cherries, and then they're put into a machine that takes the skin and pulp off it, a de-pulper I think it's called. And then you're left with the bean. But that was just one step out of 50. They had all these other machines. They had to soak them. They had to dry them. It was really remarkable to see how much goes into a farm.

Katy Milkman: By challenging his own assumptions about the supply chain, A.J. began to have a better understanding of the complex and connected world of preparing a morning cup of coffee.

A.J. Jacobs: When I came up with the idea, thanks to my son, I thought it would be, as I said, a relatively simple experiment. I mean dozens of people I figured. But certainly not the extent that it became. It just mushroomed. It just blew up and got more and more complex. And every step of the way revealed new levels of complexity. It was exponential, and at times it was overwhelming. It was frustrating. It's like, "All right, I wish it ended there," but it never did, and it didn't have to end at 1,000. I could have asked them, and they would've given me 10 more and so on and so on.

Katy Milkman: And while he couldn't thank everyone involved, a 1000 thank-yous was a good start.

A.J. Jacobs: The barista, Chung Lee, at my local Joe Coffee; Ed Kaufmann, the head coffee buyer at Joe Coffee' Jonathan Rubinstein, the founder of Joe Coffee; Richard and Alice Rubinstein, Jonathan's parents who invested in the very first coffee shop; other key Joe Coffee staff, including Tim Hitten, manager; and Frankie and Tim, Gabriel Rubinstein, the employees of Mazzer Coffee Grinders, which ground my coffee beans; Thunder Group, makers of the strainer used at Joe Coffee …

Katy Milkman: A.J. Jacobs is an author, journalist, lecturer, and human guinea pig. He's written several New York Times bestsellers, including Thanks a Thousand about his journey to better appreciate coffee. You can find a link to the book in the show notes and at schwab.com/podcast.

By now, without a doubt, you've caught onto the gist of the episode, which is that there's often a substantial difference between what we think we understand about a thing or a concept and what we discover we actually know when we're required to explain it. This psychological effect is known as the illusion of explanatory depth. From zippers, to locks, to coffee, to financial instruments, to government legislation, this illusion can trip us up in consequential ways.

Steven Sloman is a professor of cognitive, linguistic, and psychological sciences at Brown University, where he studies how people reason, make decisions, and form attitudes and beliefs. He joins me to explain this phenomenon and his research on it.

Hi, Steve. Thank you so much for taking the time to talk to me today.

Steven Sloman: Oh, such a great pleasure to be here.

Katy Milkman: I'm really excited to dive into the illusion of explanatory depth, and I was hoping we could actually just start with a definition. What is it exactly?

Steven Sloman: Well, the illusion of explanatory depth is that people think they understand things better than, in fact, they do. So experimentally, you can show this by first asking people how well they think they understand something. So this was first demonstrated with simple objects like zippers and ballpoint pens and toilets. So you ask people how well they think they understand how they work. And then you ask them to explain how in fact they work. And then again, you ask them how well they think they understand, and what you find is that their sense of their own understanding after having just tried to explain is lower than it was at the beginning. So it's people themselves admitting that they don't understand how something works as well as they thought.

Katy Milkman: That's really fascinating. What drives this bias, I'll call it, if you agree, it's a bias, why is it that we think we understand things deeply until we have to explain them?

Steven Sloman: Yes, I do think it's a bias. We're biased to think that there's knowledge in our heads that isn't in our heads, but it's out there. So I think the explanation is that we live in a community of knowledge, and we depend on others for much of the information we have. So the bias is a result of failing to distinguish the knowledge that's in our own heads from the knowledge that's in other people's heads.

Katy Milkman: That's really interesting. Do you have a sense of why it is that I can't distinguish what's in my head from what's in other people's head? That is, I as an expert on decision-making, I think I do actually have a decent handle on at least a few things in that decision-making literature. Why is it that I would think I have a handle on ballpoint pens and how they work or how my toilet works and not recognize the distinction?

Steven Sloman: Well, I think that the distinction matters in our very specialized world today where we live on credentials, and we are all evaluating each other all the time. But we evolved in an environment which it just didn't matter whether the knowledge was in our own heads or the heads of our other tribe members. So I think the reason that we fail to make the distinction is because for most of the time it's not an important distinction. That is most of the time we're collaborating with other people and depending on the knowledge that sits in our tribe. We're talking about the fact that when we make decisions, most decisions when we're acting in the world, we're acting with other people. And so the phenomenon arises simply because we depend on those other people for our decisions and actions.

Katy Milkman: What can we do to de-bias this illusion? I know you've done some work that shows there are strategies that can help reduce it.

Steven Sloman: So the first question is do we want to de-bias it? Does it matter?

Katy Milkman: Good point.

Steven Sloman: And most of the time, I'm not sure it does, but here's a case where it really does. You find the illusion in the political domain as well, not just when we're talking about simple objects. So my entree to this world, to the illusion, was doing work with some colleagues showing that you find exactly the same illusion with political policies and social policies.

Katy Milkman: So just to be clear, if you and I are having a conversation about a border policy or a policy on how we're going to upgrade the nation's infrastructure, I would think I know more about how that proposed policy is going to work than in reality I do if I'm forced to explain it.

Steven Sloman: Exactly. And so the problem with that is hubris. The problem is that when we're talking in the social policy domain, we think we understand things better than we do. And that may explain why we feel so strongly about our positions these days. In other words, I think it's actually an explanation for polarization or a partial explanation for political polarization.

So how do you de-bias? Well, the experimental procedure is actually a de-biasing technique, that is you ask people to explain. So, if we're having a conversation about infrastructure, what's going to happen with most people is that they're going to try to explain, and they're going to discover that they have very little to say because they don't really understand how it works. And so the de-biasing, it's an interesting question where exactly the de-biasing comes from. Why does the attempt to explain puncture our illusion of understanding?

And my best guess is that the answer is that when you're asked to explain, you have to talk about something that is external to you. You're not talking about your opinion. You're not talking about why you have the position you have on this policy. Rather you're talking about the policy itself and what its consequences in the world will be. And I believe that externalizing things sort of separates them from you, so you're thinking about them mechanistically, but you also don't have the same investment in being right. So I think it's a way to achieve compromise.

Katy Milkman: Steve, you've talked a little bit about one context where the illusion of explanatory depth is important, in the context of polarization, but I'm curious if you think there are other settings where this bias can be pernicious. Are there places outside of wanting to have a conversation where we can reach a middle ground where the illusion of explanatory depth is something that can lead us to make big mistakes?

Steven Sloman: Oh, yeah. I think there are plenty of such contexts. I mean, any context in which there's the potential for conflict is one in which it's possible the potential for conflict arises because of hubris on the part of the people who are engaged.

I hate to say this, but sometimes when I'm talking to my wife, I think I understand what we're talking about probably better than I do. And if I could come to a more accurate understanding of my own understanding of her intentions and of what caused the conflict, then I would probably be more forgiving, less sure of myself, and we could have a more productive conversation. I think this is true in many businesses, many committee meetings, many faculty meetings.

One of the basic facts about people is that we are hard to persuade. We take our positions and we take them strongly, and we tend to be intransigent. So I think that lowering the temperature in general is a good thing. And in particular, I think that thinking about things mechanistically rather than thinking about our values kind of takes us out of the picture. We become less egocentric and can have more productive conversations.

Katy Milkman: Could you walk us through one of your studies on how talking people through what they really understand or having people work through their actual understanding can reduce polarization?

Steven Sloman: Sure. So the procedure is largely what I described earlier with regard to objects. That is, you take some policy that you're thinking about. And so, in our studies, one of the policy issues was whether or not there should be a flat tax on all Americans. And you ask people how well they understand the policy and what its implications would be. And generally people say, "Oh yeah, I understand it." On a one to seven scale, they'll give a four or five or something. And then you say, "OK, now explain the policy in as much detail as you possibly can." And so people set off, and they very quickly come to the realization that they don't understand the policy enough to draw out implications enough to explain how exactly it's going to manifest out in the real world.

So then again we ask them, "Now, how well do you think you understand the policy?" and their judgments are reliably lower. But the other thing we do is we say, "Has your attitude changed at all?" That is, we ask them on a scale from "I disagree completely with the policy" to "I agree completely with the policy" where they are. And we ask them that question both before and after trying to explain it. And what we find is that they are closer to the midpoint of the scale. That is their judgments are more moderate. They're less extreme after having tried to explain than before having tried to explain. So, in terms of policy polarization, that is the extent to which the people that we're talking to are extremists on this policy, we've made them more moderate simply by asking them to explain.

Katy Milkman: That's really interesting and really encouraging. I learned a lot from this conversation. Thank you so much for taking the time to talk to me today, Steve. I really appreciate it.

Steven Sloman: Well, thanks for a set of really penetrating questions. It was a pleasure talking to you. Thanks, Katy.

Katy Milkman: Steven Sloman is a professor of cognitive, linguistic, and psychological sciences at Brown University. He's also the author of a terrific book with Philip Fernbach called The Knowledge Illusion: Why We Never Think Alone. You can find a link to Steve's book in the show notes and at schwab.com/podcast.

For help decoding complex financial concepts and the specific decisions we make in our financial lives, including how the biases we explore on Choiceology could impact your portfolio, check out our sister podcast, Financial Decoder. You can find it at schwab.com/financialdecoder or wherever you get your podcasts.

As Steven Sloman pointed out, the illusion of explanatory depth can lead us to overestimate our understanding of everything, from simple technologies to financial products, which puts us at risk of making decisions based on faulty logic. For example, if you're sure you understand how shorting a stock works and decide to place a sell order only to discover later exactly what you've gotten yourself into, you may be quite sorry.

The good news is how simple it is to de-bias yourself. By forcing yourself to explain in detail potentially to someone else what it is you think you understand, you can uncover just how clear you are on, say, the mechanism in a simple lock or how shorting a stock really works.

So before you make your next big decision that requires understanding the inner workings of a policy, technology, financial product, or, well, anything really, test yourself. Can you explain how that policy, technology, or financial product works to someone else? And are you just as confident in the quality of your planned decision after you've tried your hand at providing an explanation? If so, you're all set. If not, it's time to rethink and then congratulate yourself on dodging a bad choice. By disabusing yourself of the illusion of explanatory depth, you'll be prepared to potentially make better judgments about everything, from politics to personal finance. All it takes is a little elaboration.

You've been listening to Choiceology, an original podcast from Charles Schwab. If you've enjoyed the show, we'd be really grateful if you'd leave us a review on Apple Podcasts, a rating on Spotify, or feedback wherever you listen. You can also follow us for free in your favorite podcasting app. And if you want more of the kinds of insights we bring you on Choiceology about how to improve your decisions, you can order my book, How to Change, or sign up for my monthly newsletter, Milkman Delivers, at katymilkman.com/newsletter.

Next time, the story of a perennial curse in sports that may be explained by a basic law of statistics.

I'm Dr. Katy Milkman. Talk to you soon.

Speaker 7: For important disclosures, see the show notes or visit schwab.com/podcast.