In A Nutshell
The above statement got everyone looking for proof, because even a rotter of a movie can’t throw around scientific statements without there being some truth to them. It turns out that this fact is a fact, true, and very difficult to believe. Experiments from the 1960s show that it even works in rats and mice.
The Whole Bushel
The scientist who came up with this experiment is Dr. James V. McConnell, assistant professor of psychology at the University of Michigan (USA) in the 1960s, who had a hunch that planarians (flatworms) could be trained to run mazes. He proceeded to do so. He first trained them to be afraid of the heat of a bright light, which, after many attempts, made them curl up to protect themselves. Soon they were curling up whenever they felt the heat or saw the light.
Then he chopped them up and fed them to planarians unaccustomed to the bright light and heat. This second group curled up the first time he shone the light on them. McConnell was naturally thrilled and took the experiment to the next level. He taught a group of planarians to run a maze. This took a long time of course, since planarians are very simple animals, and the species in question was microscopic.
After 150 attempts, the flatworms could find their way correctly every time. McConnell pronounced them knowledgeable of how to run the maze. Then he first tried cutting the head off one worm and grafting it onto another. This didn’t work because the head wouldn’t stay on. Then he ground up this batch of worms and tried injecting them into a second group. This failed because the worms were about the same size as the point of the needle, which crushed them.
He might have been stumped at ths point, had it not been for a worm enthusiast named Jay Boyd Best, who wrote him a letter suggesting that feed the worms to a particular species of cannibalistic planarian. So McConnell acquired some specimens of this species of flatworm and fed the trained group to this new group. The new group was able to run the maze correctly the first time, but not correctly every time until they practiced 100 times. He trained a separate control group to run the maze, and this group required about 150, just like the group he ground up.
McConnell became famous for a time, even though the very premise of his research seemed too much like a Frankenstein story to grab the scientific community. He did, however, receive a fast promotion to full professor and made it onto some science shows like Watch Mr. Wizard. Scientists who found his work interesting then took the next step, performing the same experiment with mice and rats, and they found that it still worked.
Such experiments continue to this day and continue to raise eyebrows.