> "Rozenblit and Keil (2002) have demonstrated that people tend to be overconfident in how well they understand how everyday objects, such as toilets [...]"

I'd be really interested to see what misconceptions people had about flush toilets, but Rozenblit and Keil's paper doesn't seem to really expand on this. (Assuming I found the right paper: http://www.yale.edu/cogdevlab/aarticles/IOED%20proofs.pdf%20... ?)

I've personally assembled and installed a toilet so I am confident that I have an accurate view of how toilets work, but that experience wasn't exactly illuminating; I already knew how they worked. Toilets are pretty simple, anyone who has ever opened the tank of one and looked at it for a minute or two probably has it figured out.

Edit: When other questions from that study include things like " How the liver removes toxins from blood", I don't doubt that they found an overall trend, but it bothers me that a paper like that could include mention of asking questions about toilets, not actually say what people got wrong about toilets, and then because of that paper it is taken as truth that people don't know how toilets work.

The lack of understanding isn't necessarily a "misconception" -- it may just be incomplete knowledge of the entirety of the system.

I think the question "How does a toilet work?" is much like the question "What happens when you type 'google.com' into your browser and press enter?"[1] I'm sure I have a sufficient understanding of the general idea (e.g. flapper and siphon, or parsing and DNS lookup), but I'm well aware I couldn't reproduce or accurately describe the whole system/process on my own.

[1] https://github.com/alex/what-happens-when