A tale of stone erosion and insect behaviour illuminates the importance of asking more whys, writes Rory Sutherland.
Back in the late 1980s, the National Park Service (NPS) in the US were concerned about the erosion of Washington DC's Lincoln Memorial. So they asked the maintenance staff why the stone was decaying.
They were told that it was necessary to use high-power sprays as often as once a fortnight in order to clean the masonry.
Why so? It seems they needed to spray to get rid of the bird droppings that accumulated on the building in huge quantities.
So they...