Believing we understand: the illusion of explanatory depth in politics
We often feel we understand a public policy, until the moment we are asked to explain how it works. This gap has been measured, and it affects opinions themselves.
Knowing that, believing we know how
In 2002, Leonid Rozenblit and Frank Keil published a series of experiments that have become classics. Participants rated their understanding of everyday objects, such as a zip or a flush toilet, and then had to explain step by step how they worked.
After the exercise, they revised their estimate markedly downwards. The feeling of understanding rested on familiarity with the object, not on knowledge of its mechanism. The authors named this gap the illusion of explanatory depth.
The experiment applied to public policy
In 2013, Philip Fernbach, Todd Rogers, Craig Fox and Steven Sloman applied the same protocol to political measures. Participants had to explain how a policy would produce its effects, and not why they supported or opposed it.
In their results, explaining the mechanism reduced the feeling of understanding and made positions less clear-cut. Simply asking for the reasons behind one's opinion did not produce this effect, since it amounts to drawing on arguments that are already available.
Why the illusion is so comfortable
Steven Sloman and Philip Fernbach developed the idea in The Knowledge Illusion, in 2017. No one masters on their own how a society works: we rely on knowledge distributed among experts, institutions and those close to us, and we easily mistake their knowledge for our own.
This cognitive division of labour is indispensable, not shameful. The problem arises when it is forgotten, and we credit our own reflection with a confidence that in reality comes from those around us or from a trusted source.
What the effect does not say
The illusion does not signal a lack of intelligence: it affects everyone, whatever their level of education or political orientation. Nor does it prove that a position is wrong, only that the confidence placed in it exceeds what one knows.
Later replication attempts obtained weaker or inconsistent effects on the moderation of positions. The drop in the feeling of understanding seems more robust than its extension to opinion, and caution is called for before seeing it as a remedy for polarisation.
An exercise to try
Choose a measure on which your view is firm, and describe in writing, step by step, how it would produce the expected effect. Who acts, with what means, within what time frame, and what could prevent the planned sequence?
If the explanation quickly stalls, that is no reason to change your mind. It is an indication of the nature of your position: it may rest on a value or on trust placed in others, which is legitimate provided you know it.
For a questionnaire, the consequence is useful. Items bearing on principles elicit sturdier positions than those that presuppose knowing the details of a scheme, on which many people answer with more assurance than knowledge.
Key points
The feeling of understanding often rests on familiarity, not on knowledge of the mechanism.
Explaining how something works reduces this assurance, which listing one's reasons does not.
The effect on the moderation of opinions is more fragile than the effect on perceived understanding.
This article describes documented mechanisms and disagreements. It recommends no position, no party and no vote, and commits to no reading other than that of the work it cites.
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