The human mind has an infinite capacity for fooling itself. One biology teacher tells of being challenged by a student when he said that, contrary to common myth, both sexes had the same number of ribs. The myth traces back to the story of Eve having been made from a rib of Adam. The teacher had the student count the ribs on the male skeleton, and lo and behold, she came out with one less than the female number. He asked her to repeat it, with the same result. It wasn't until he took her hand and they touched each rib in order, counting aloud, that the correct number appeared.
This was not an attempt at duplicity by the student. Her
"knowing" that there was one less rib in males caused her miscount.
Scientists, too, are susceptible to such errors, which is why blind tests are used when
possible. If a researcher studying size, say, in kangaroo rat skulls, has the identity
of the skulls being measured concealed, it helps avoid such unconscious bias and
erroneous results.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.