Hysterically funny. The author went to great lengths to call her peers a bunch of myopic, blinkered idiots in the most polite and academically tortured ways. Apparently a bunch of Cognitive Science has been devoted to University intellectuals dragging ordinary people into laboratories, giving them tests that University intellectuals are good at, and then writing with dismay at how stupid most ordinary people are because they don't think like the people giving the tests.

So the author had the bright idea of wandering around "in everyday life" and seeing how these abysmally stupid people managed to stay alive. She found that a bunch of people who couldn't do basic division managed to spot a bargain between two products in a supermarket over 98% of cases.

Unfortunately, researchers were not run through "shopping cart math" to provide a comparison, but it's pretty clear who would win.