The finding that when trained flatworms (planarians) are fed to untrained worms, the untrained worms behave as though they have learned the task is called memory transfer or behavior induction.
It has been suggested in THE STRAIGNT DOPE that when trained worms are fed to untrained worms, some sort of “general factor” is actually transferred to the untrained worms and that this chemical factor “prepares worms to learn faster” or facilitates learning. That is, it has been suggested that memory is not actually transferred, only a tendency to learn faster.
This interpretation for the well-documented findings of transfer of memory by cannibalism in flatworms ignores the observation that when untrained worms are fed trained worms, they do not just learn faster—they begin to perform the task (e.g., classical conditioning) as though they already have learned it. They do not just learn faster, they make conditioned responses on the very first learning trial.
Although James McConnell and Robert Thompson, who discovered these findings, interpreted them as supportive of the view that memory is chemical in nature and that it can be transferred from one worm to another, no single interpretation of these findings (successfully replicated many times even by high school students) have never been generally accepted, and the phenomenon has never fully explained.
Scientists have repeated these studies using RNA-rich brain extracts from trained rats and using untrained rats as recipients that are injected with the trained brain material, and have replicated the effect found in the worm experiments. There have also been many failed attempts.
All these experiments have been so controversial that funding for them became unavailable and scientists moved on to other research topics without ever adequately explaining these findings that were acquired in well-controlled worm and rat experiments.
Hiya, agolub, welcome, and how d’ye’do! When posting about articles, either by Cecil or a lesser being, it is helpful to link to the article. You can do it the fancy way, like this, using the URL tags (or the URL button above the reply box). Or, it can be done as simply as copying and pasting the address to the bottom of your post, like so:
It’s a Staff Report by Doug, rather than a Cecil column, and I expect this will move forum presently.
I’m not sure the suggested funding was ever crucial in the first place. No, what’s striking about the whole worm memory saga is that the initial paper produced an entire wave of people, often amateurs, trying to reproduce the results. I’d even guess that it’s probably one of the most repeated experiments in the whole of 20th century science. A large part of the claim’s fame and its impact on popular culture is precisely that they didn’t need formal funding at all.
The standard argument against - touched on in the report - is that what looks like a trivial experiment is actually rather complicated to do convincingly. You thus get a hoard of inexperienced people reporting successes and others pointing to flaws in the experimental designs. That’s an inherently frustrating situation all round - and not just for those who want to claim that the matter was dismissed “without ever adequately explaining these findings”. Nor is it obvious that throwing funding at the issue would have resolved any of the disagreements.
In historical perspective, it was an odd claim that never went anywhere significant, but whose popular half-life was evidently and unsurprisingly substantially longer than its scientific one.
Here’s a recent study that is similar and interesting. It appears that something gets passed along but not through DNA (offspring of rats trained seem to retain learning even when raised by other rats):
The item in question is a Staff Report written by Doug, and not one of the Straight Dope columns written by Cecil. Accordingly, I’ll move this thread to the Comments on Staff Reports forum.