Researchers at the New Jersey Institute of Technology have been studying glass knifefish for a little while now to learn more about “station keeping.” That’s a sort of autonomous phenomenon in some animals in which they can move and hide in the most ideal ways for keeping hidden. One of the researchers had an idea (and when a researcher has an idea, that’s probably when we should start getting worried) to see if station keeping is an instinctive action or a learned skill.
The team developed a special tank for their subject fish that has its water movements synchronized to the fish’s eyes. Basically, they were trying to trick the fish into thinking it was moving while sitting still and vice versa. “We’ve known for a long time that these fish will follow the position of their refuge, but more recently we discovered that they generate small movements that reminded us of the tiny movements that are seen in human eyes,” said associate professor Eric Fortune. “That led us to devise our augmented reality system and see if we could experimentally perturb the relationship between the sensory and motor systems of these fish without completely unlinking them. Until now, this was very hard to do.”
Surprisingly, the fish was actually able to discern its virtual environment from a real one. It moved differently than it would have in a normal current, adjusting its eyes to de-synchronize from the water. If this bizarre experiment proved anything, it’s that fish (or at least glass knifefish) receive feedback on the world from their own bodies, rather than just their eyes.
