Shark eye

I attended a talk yesterday about sharks. At one point the speaker, an expert on shark behavior who seemed to be a genuine fan of the species, explained that sharks use the stereo disparity between their two eyes to judge distance.

I asked whether, if a shark had the use of only one eye, it could judge distance via motion parallax. The speaker said, somewhat tongue in cheek, that such a hypothesis would be difficult to test, since IRB regulations governing ethical research would probably not approve poking out a shark’s eye in the name of science.

This was the point when I realized that the speaker, for all his putative love of sharks, clearly did not think of sharks as individual sentient beings.

After all, if you were going to ask the same research question about a human, it might occur to you to cleverly get around those pesky IRB regulations by covering the human’s eye with an eye patch, rather than, say, removing one of the human’s eye balls. .-)

Coincidentally, that very same evening I visited someone who owns one of Marcel Duchamp’s original Rotoreliefs. These are works of kinetic art consisting of designs on flat cardboard circles spun on a turntable. When the turntable spins, the flat disks appear three-dimensional.

I told my host about the shark story, which suddenly had more resonance because Rotoreliefs work much better if you close one eye. In other words, they are a perfect example of motion parallax in action. In fact, according to Tompkins’ biography of Duchamp, scientists have actually tried using these works of kinetic art to restore depth vision for people who have lost the use of one eye.

How appropriate that Duchamp’s work leads to thoughts about sharks. After all, his concept of the ready-made led the way for such later works as Damien Hirst’s “The Physical Impossibility of Death in the Mind of Someone Living”, which is essentially a pickled shark.

I strongly suspect, based on this work, that Hirst does not think of sharks as individual sentient beings.

There may be artists out there who do. I haven’t found any yet, but I’ll keep an eye out.