We've heard or read about computer filters that let through selected material from the internet while ignoring stuff deemed harmful to children. We have our own filter for the universe. Everything our brain perceives is accessed through nerve impulses; such impulses going to one part of the brain may be perceived as sight, while that to another part as pain. The outside world is accessed by transduction: the changing of one type of energy to another—in our case, to nerve impulses. Thus light, pressure waves, molecular movements, excessive pressure, and so on are transduced into nerve impulses and eventually translated in our brains as sight, sound, heat, and pain.
But the organs responsible for transduction are filters, allowing
through some stimuli while ignoring others. We don't see ultraviolet light, we
don't hear the ultrasonic cries of bats, we don't smell but a portion of the
scents available to dogs. We bring in most of what is vital to us, but our filtered
input distorts the real universe just as a computer filter distorts the content of the
internet.
Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.
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.