I recently watched the film Phantoms. A scientist in the movie claimed that flatworms were able to "consume" memories from other flatworms. The specific example was that of learning the solution to a maze by digesting ground up flatworms that had already solved the maze.

I don't understand how memories could possibly survive being ground up, let alone survive an entire digestive system, and be recreated from its parts. But a quick searching of the internet reveals other discussions on the topic including comments that someone actually conducted such an experiment. Here are two such articles: Example 1; Example 2.

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    I was looking forward to shutting this one down hard and fast, but after reading the theories and supporting evidence, I skeptical as well.
    – Alain
    Commented Jun 22, 2011 at 18:54
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    Wow, those are excellent example articles. +1! The quote "On the other hand, the reports of transplant patients having memories related to the donors are legion" from the first example was a big surprise to me, and would be another good question.
    – Beofett
    Commented Jun 22, 2011 at 19:20
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    I seem to remember sagan decrying this in demon haunted world but I might be wrong, Commented Jun 22, 2011 at 23:53
  • @Monkey: thanks for the hint, I have searched for that (on Amazon preview) and I have added the quote into my answer.
    – Suma
    Commented Jun 23, 2011 at 8:32
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    Once these flatworms learn how to live as parasites in human heads then rule humanity with wanton brutality, we'll have the making of a great sci-fi show.
    – user11643
    Commented Sep 17, 2017 at 19:57

1 Answer 1


No, they cannot. They were experiments done which indicated the possibility, but the results were never reproduced, therefore it is most likely their setup was somehow wrong. Moreover, no mechanism which could cause such effect is known.

Tracing the original experiment, I have found the following:

Investigations of the cellular bases of memory

In 1962 McConnell performed an experiment which appeared to be even more dramatic demonstration of this. After training some planaria he ground them up an fed them to other planaria. These animals were quicker at learning the light-shock association than controls who were fed ground-up untrained worms.

The claim is weaker here, only only they were quicker at learning, not learning everything.

Wikipedia on James V. McConnell says:

Although well publicized, his findings were not completely reproducible by other scientists and were therefore completely discredited (for review, see Chapouthier, 1973).

The maze question was asked at snopes forum, and the linked Everything2 topic seems a bit confused, giving the date of preceding 1953 experiment.

There is a comment to the topic there by dmd, agreeing with the Wikipedia negative conclusion:

In the interests of maintaining high scientific standards, I feel obligated to note that before the cold fusion debacle, McConnell's planaria study was the standard by which Bad Science was judged. "McConnell's research program with planaria collapsed when other scientists failed to replicate the phenomenon of memory transfer." -- American Psychologist 51:589-598.

McConnell's results on transferred memories did not hold up. A great discussion of the failure of McConnell's research can be found in The Making of Memory: From Molecules to Mind by Steven Rose (1993, ISBN 0385471211).

It is also mentioned by C. Sagan in The Demon-Haunted World, ISBN: 978-0345409461, p. 221 as a known example of pseudoscience:

Typical offering of pseudoscience and superstition ... are ... "the aledged discovery that untrained flatworms can learn a task by eating the ground-up remains of other, better educated flatworms".

For completeness, here is a reference to the relevant original studies (copied from the everything2 page):

  • McConnell, JV. 1962. Memory transfer through cannibalism in planarians. Journal of Neuropsychiatry 3 (Supplement no. 1): 542-548.
  • Hartry, AL et al. 1964. Planaria: memory transfer through cannibalism re-examined. Science 146: 274-275.

If, as it seems, no one was able to reproduce it since then, it most likely means the theory is wrong.

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    Do you know what cold fusion debacle one of your quotes are referencing?
    – Kit Sunde
    Commented Jun 23, 2011 at 2:08
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    that'd be this debacle en.wikipedia.org/wiki/…
    – david w
    Commented Jun 23, 2011 at 2:19
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    I've seen this one repeated in sci-fi many times, which is why I think it has persisted for so long Commented Jun 23, 2011 at 20:36
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    "they were quicker at learning" Probably because they were fed something more nutritious than their normal fare. Repeat it with a double blind study with a real control group (fed worms that did not learn the maze) and let's see what happens.
    – Adam Davis
    Commented Jun 24, 2011 at 15:14
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    @Adam: Did you miss the part about "controls who were fed ground-up untrained worms"?
    – endolith
    Commented Jul 9, 2011 at 16:28

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