There was a similar experiment where a research ground up flatworms and fed them to other flatworms and they learned the behavior faster. [1]
I suspect the worms aren't "learning" anything, but are simply adapting an inbuilt behavior based upon local conditions. If local conditions cause a hormone or epigentic shift, that would appear the behavior was learned and could be preserved when the brain was regrown. It would also explain how feeding the remains of other worms could "teach" it something. In reality it could just be an adjustment of hormone levels.
I was thinking that as I read it. Maybe their outer cells are just getting use to something and an evolutionary fitness mechanism keeps those other cells seeking whatever provides it nutrients.
I mean it get into the definition of what _memory_ is. When humans talk about muscle memory, we're not actually talking about memories actually being held in those muscles. We're just training our brain an nervous system to be faster and more precise at a given task.
When we train certain animals, their learning may have nothing to do with a central nervous system at all. And even the concept of "learning" could be a human personification we apply to an animals when really it is simply adapting or has some type of evolutionary fitness or propensity to repeat certain tasks that bring it food or warmth.
On a side node, I really dislike it when people say "our feet were designed to" or "this animal's webbed feet are designed to." I always try to say they "evolved to" or "adapted to." It's similar to when people say "It's suppose to rain all well," when you should really say, "They're predicting rain all week."
Yes! I sometimes wonder if Frank Herbert was aware of this study, reported in the press [1] three years before the publication of Dune, with its tales of transgenerational memory transmission and sandworms..
I suspect the worms aren't "learning" anything, but are simply adapting an inbuilt behavior based upon local conditions. If local conditions cause a hormone or epigentic shift, that would appear the behavior was learned and could be preserved when the brain was regrown. It would also explain how feeding the remains of other worms could "teach" it something. In reality it could just be an adjustment of hormone levels.
[1] https://en.wikipedia.org/wiki/Planarian#Regeneration