Originally Posted by Rebecca Lawson

In 2002, Leonid Rozenblit and Frank Keil argued that, in particular, we overestimate our ability to explain how things work - whether artefacts like greenhouses and bicycles, or natural phenomena like tides and rainbows. They suggested that this illusion of explanatory depth is especially severe for objects with visible parts. Rozenblit and Keil's conclusions were based only on people's self-ratings of the quality of their explanations. I wanted to extend their work to measure how accurate people's explanations really are, to see how well people understand how everyday objects work. The bicycle is an obvious choice to test this.

Firstly, bicycles are familiar objects even for non-cyclists. I have given the test to over 200 students and parents coming to Open Days at the University. Over 96% had learnt to cycle as children with a further 1.5% learning as adults and less than 3% never having learned. Also 52% of this group owned a bicycle. Sadly, the figures on actual cycling were low, with just 1% cycling most days, 4% cycling around once a week and 9% cycling about once a month. The vast majority either never cycle (52%) or rarely do so (33%). Nevertheless, even for these non-cyclists, bicycles are a common sight. Secondly, if Rozenblit and Keil are correct, people should greatly over-estimate their understanding of how bicycles work because bicycle parts are visible and they seem to be simple, mechanical devices.