Flatworms learn from eating other flatworms

[snopes]

Comment: I have heard it said that a flatwork that eats another flatworm
will absorb the knowledge of the eaten flatworm. In the book Phantoms by
Dean Koontz, he tells the story of the flatworm in a maze, and when it
reaches the end, it is chopped up and fed to another flatworm who them
manages to find his way to the food the first time.

Is there any truth in this?

[Horse Chestnut]

^ (Cannibal worm head)

Well, the experiment was conducted, but everything after that is still debated.

I'm inclined to lean towards the "slime trail" theory, myself.

[Lancastrian]

I know I absorb the knowledge of those who I consume, but I'm a more complex organism than a flatworm, so I can't speak to how they do it.

I'm actually reading that book right now.

The flatworm article at Wikipedia says

In 1955 Thompson and McConnell conditioned planarian flatworms by pairing a bright light with an electric shock. After repeating this several times they took away the electric shock, and only exposed them to the bright light. The flatworms would react to the bright light as if they had been shocked. Thompson and McConnell found that if they cut the worm in two, and allowed both worms to regenerate each half would develop the light-shock reaction. In 1962 Mconnell repeated the experiment, but instead of cutting the trained flatworms in two he ground them into small pieces and fed them to other flatworms. Incredibly these flatworms learned to associate the bright light with a shock much faster than flatworms who had not been fed trained worms. This experiment showed that memory could perhaps be transferred chemically. The experiment was repeated with mice, fish and rats, but it always failed to produce the same results. The perceived explanation was that rather than memory being transferred to the other animals, it was the hormones in the ingested ground animals that changed its behaviour.[1]

McConnell believed that this was evidence of a chemical basis for memory, which he identified as memory RNA. Although well publicized, his findings were not completely reproducible by other scientists and were therefore partially discredited.

[AliBaba]

Comment: I have heard it said that a flatwork that eats another flatworm will absorb the knowledge of the eaten flatworm.

Resistance is futile, you will be assimilated....

No disrespect to flatworms, but seriously, exactly how much knowlege could we really be talking about here?

Ali "slow work day" Baba

[Joostik]

If they did, eating eachother would give them an evoutionary advantage. Is there anything known about cannibalism among flatworms?

I'm having trouble finding a free online source, but here's a posting by a biologist, anyway, who confirms what I've heard elsewhere - the apparently absorbed memory is actually a result of the flatworms following other worms' trails in the maze.

The story has been around for a while; it was the premise of some Alan Moore fiction I read around 1986, and I had seen the idea before.

[Bonnie]

Believe it or not, here's an earlier thread (from the old board) that gets around to discussing "memory transfer" experiments in flatworms,

http://msgboard.snopes.com/message/ultimatebb.php?/ubb/get_topic/f/104/t/000651/p/1.html

Bonnie "tanks for the memory" Taylor

[Tenko]

I read a sci-fi anthology, Introductory Psychology Through Science Fiction by Katz, that mentioned this. In it, though, it says light and electroshock stimulation worked just as well, and that the ground up worms worked too, because they also offered stimulation.

While looking under microscopes at flatworms, my 9th grade Biology teacher said that this was true. I had no idea it was debateable.