The importance of understanding toilets and politics

tl;dr: Understand things before you have an opinion

In today’s world, there is much discussion about fake news, about political movements becoming more extreme and about a divided society. Unfortunately, I rarely hear anyone discuss why our society is diverging and what can be done to prevent this. So please bear with me while I introduce a psychological issue which is a promising tool for cooling off and understanding the origin of heated political disagreements.


Picture a flush toilet and ask yourself: how well do you understand how this toilet works? Maybe rate it from 1-7? Are you above the average, which would presumably go for a 3 or 4? Now please stop reading and explain to yourself how that toilet you (hopefully) use every day works! Go through every step before reading on.

Did you explain where the water comes from, why there is water down there in the first place, how the toilet knows how much water to flush, how it refills the correct amount,…? Do you still think you understand it as well as you assessed a few seconds ago?

You may be under the illusion of explanatory depth, termed and examined by Leonid Rozenblit and Frank Keil in 2002, in short, IOED. People feel they understand complex phenomena with far greater precision, coherence and depth than they really do.

One of the most important reasons for IOED is the confusion of higher and lower levels of analysis. Most complex systems are hierarchical in terms of explanations of their natures. In explaining a cell phone, one might describe the components such as a camera, buttons, loudspeakers and apps. If then asked what a camera is, you might start explaining flashes, apertures, lenses etc. The illusion of explanatory depth occurs when we gain a surface layer understanding and then stop asking any questions!

Another reason for IOED is the rarity of production: we rarely give explanations and therefore have little information on past successes and failures which would help us classify our knowledge. In contrast, we often tell narratives of events or retrieve facts; hence it is often easy to assess our average level of knowledge in these cases by inspection of past performance.


In case I you are still reading (thanks, I guess), you may be starting to wonder why I am boring you with toilets. To be fair, you will (almost) never need to know how these things work, this is simply the division of cognitive labor and ultimately how our society can function on a high level.

But of course, the IOED extends well beyond toilets, to how we think about scientific fields, mental illnesses, economic markets, politics and virtually anything we are capable of (mis)understanding. Not understanding how toilets work is one thing, not understanding the history of Jerusalem and all the involved parties and still having a strong opinion on how this should be handled – that is a very different thing. Today, the IOED is profoundly pervasive, given our access to infinite information which we consume in large quantities – however, most do this in a superficial manner. Most of us consume knowledge widely, but not deeply!

Fortunately, understanding the IOED allows us to combat political extremism. In 2013, Philip Fernbach and colleagues demonstrated that the IOED underlies people’s policy positions on issues like single-payer health care, a national flat tax, and a cap-and-trade system for carbon emissions. As in Rozenbilt and Keil’s studies, Fernbach first asked people to rate how well they understood these issues, and then asked them to explain how each issue works and subsequently re-rate their understanding of each issue. In addition, participants rated the extremism of their attitudes on these issues both before and after offering an explanation. Both self-reported understanding of the issue and attitude extremity dropped significantly after explaining the issue – people who strongly supported or opposed an issue became more moderate. These studies suggest that IOED awareness is a powerful tool for cooling off heated political disagreements.


In a time where income inequality, urban-rural separation and strong political polarization have fractured us over social and economic issues, recognizing our own (at best) modest understanding of these issues is a first step to bridging these divisions.

The next time you are having an intense debate about Trump’s politics, unconditional basic income or your educational system, take a step back and contemplate on whether you are in a position of real understanding or rather throwing superficial arguments at one another.

And as always, stay curious!


For deeper insights on this topic, I can highly recommend Dr. Fernbach’s book, “The Knowledge Illusion: Why We Never Think Alone“, Keil and Rozenblit’s original paper: “The misunderstood limits of folk science: an illusion of explanatory depth” and, of course, the Wikipedia page on flush toilets!