In 1953, Dr. James McConell
began performing labyrinthine experiments with planarian worm
s (Dugesia dorotocephala
) at the University of Michigan
, training them, using the punishment
operand of classical conditioning
, to learn
over a period of months to consistently follow the most effective route through a maze.
This is all old hat. Planarian worms are cheaper to buy and keep alive than lab rats. Nothing new. But it was what he did next which raised a few eyebrows.
Keeping track of how long it had taken the entire first group of worms to successfully learn how to run the maze, he killed them all and fed the remains to a second group of hitherto untrained worms. Keeping this second group and a third control group of planarians (on a normal, non-cannibalistic diet) isolated, they were all trained to run the same maze using the same method as with the first group of worms.
The control group of worms took roughly the same amount of time to learn to run the maze as the first batch had, but the group which had eaten the first, educated bunch learned to run the maze considerably faster than both the control group and the original group on which they had dined. It was as though by eating the first group of learned worms, they had in some small way attained a not insignificant glimmer of the knowledge which had been previously imparted unto their dinners.
Similar results were later got when unschooled worms were injected with the RNA
of successful maze-runners, leading to a controversial theory of the relation between RNA and memory
, and later similar experiments produced further similar results in rats, goldfish and canaries.
There are some problems with this almost-50-year-old experiment, some of which I am more qualified to effectively communicate than others, but I will attempt to present them all:
1) In natural conditions, flatworms will react to light by elongating and to shock by contracting, while in this experiment they were apparently trained in a completely topsy-turvy manner - contracting in response to light and elongating when exposed to shock, thus not only were they being trained to run a maze but to do so in complete opposition to their instincts. That raises questions and variables which weren't taken into account during the course of the original experiment, and could quite conceivably have skewed the results;
2) The propensity of planarian worms is to choose to follow a path coated in the mucous or slime trail left by a previous worm rather than to slither off in new directions. Some believe that rather than training the worms to run mazes at all, the researchers were merely establishing a slime highway that eventually all the worms figured out the onramp to. Would the subsequent dietary results indicate then that the cannibal worms would have had their natural inclinations towards following slimy paths reinforced? What exactly would the scientists have been measuring?
3) (This one is my favourite.) The most common objection to the whole experiment I've heard is that the cannibal worms were better fed, being provided the nourishing bodies of their predecessors rather than the typical merely-sustaining lab wormfood! It is widely accepted that malnutrition impedes learning in human beings - thus school lunch programs - so why not in worms as well? This objection fails to account for results attained by the RNA injections.
If anyone can explain further (or better explain the ones I have here) reasons why these experiments are not presently looked upon as tremendously scientific, I would be pleased for you to share in the subsequent writeups or to /msg me.
On a tangent to this subject matter, it was also discovered in experimentation that the regenerative abilities of planarian worms didn't just extend to physical organs but memories as well! If you cut the head off of a trained planarian worm, once it grows back the worm will be able to run mazes as effectively as before, yet if a worm is cut in half (so that each half grows back another half-worm, resulting in two worms) only one of the resultant worms will have retained the training. This shows that memory in
worms is located somewhere other than its head.
Dutch artist M.C. Escher produced a lithograph in 1959 named Flat worms (Platwormen) (viewable online at http://www.tabletoptelephone.com/~hopspage/Flatworm.jpg), depicting a structure formed from alternating tetrahedronal and octahedronal bricks with cute l'il flatworms slithering all over them. He noted that such a structure would be impractical for humans as the resulting surfaces produce neither vertical walls nor horizontal floors, but if it filled with water it would work dandy as a home for flatworms. Kibo (of Usenet infamy) points out the unutilised possibility here - Escher using worms in his works prior to the scientific establishment of both their regenerative and maze-running abilities - and hypothesizes that if only he'd known, Escher would have depicted planarian worms regenerating in the forms of moebius strips while running geometrically impossible labyrinths. Anyone with a passing familiarity with Escher's work can agree that this wouldn't be atypical for the Dutch mindbender.
For a time, experimenters in this field published a special-interest newsletter / scientific journal entitled Worm Runners Digest. The names of two articles from scientific journals dealing with the phenomena described above follow:
I am pleased as punch to finally have found a way to put comic books, Kibo, cannibalism and M.C. Escher all in the same node.