Edible Knowledge

The business about Shakespeare pills is bad science, bad sociology, bad history, though perhaps good journalism: it's a nice hook to get you interested, but it is wrong. No one ever thought that was why the work we're talking about was interesting and potentially important.

We want to know about how memory works at a variety of levels and for a variety of reasons.

In order to understand memory, like anything else, one strategy is to try to understand in the simplest possible cases. That means, on the one hand, studying people memorizing lists of words, and on the other, studying memory in the simplest system (organism) possible.

There is another reason to do that: primitive organisms are cheaper and faster to work with (at least usually).

McConnell studied memory in flatworms. That makes one ask,what is memory? Memory, at least throughout this chapter, is memory of learned behavior. So, what can you possibly teach an animal considerably dumber than an earthworm? McConnell taught them two things: one, when there is light, you're going to get a shock; two, to run a maze to get food (a Y: go left or right).

How can you tell if a worm has learned? They've learned light predicts a shock if they react to the light like they react to shocks. They've learned the maze if they go the right way more often than not.

How do you teach a worm? First, you have to get its attention. How can you tell? You have to be a worm whisperer. They didn't actually call them that, they called them Worm Runners. A shock makes a worm scrunch, but so does a bright light. A worm will never learn anything about a light so dim it can't sense it. So, you need just the right light. Worms sometimes scrunch just because they feel like it. So, a worm runner has to watch the worm until it is "calm and ready to pay attention." It would be nice, for the studies, if there was a definite criterion. But there isn't. When the worm is ready, you give it the light-shock pair. Eventually, if you are a good worm runner, the worm begins to scrunch before the shock. It has "learned" to "expect" the shock.

McConnell discovered, almost by accident, that if you fed an untrained worm ground up trained worm, the untrained worm "knows" what the worm it ate did.

That is very interesting, because everyone thought (and now does again) that memory is somehow a distributed structural property of part of the nervous system, and the experiment suggests that it is a chemical. That completely changes the way one thinks about the biology of memory. It suggests different experiments, different theories of phenomena.

So what is the reaction in the scientific community? There were two initial surprisingly strong reactions: worm running became the most popular high-school science project, and scientists who studied memory were hostile.

The two reinforced each other: the high-school students made the whole thing look suspicious and faintly disreputable, and the hostility stirred up publicity.

So, what were the criticisms? Worms can't learn. A variety of technical objections were raised, and experiments were devised to answer them, but the experiments were "never" completed because something else happened, and everyone suddenly agreed that worms can learn:

Ungar reported "edible memory" in mammals (rats and mice). After that, no one thought it worth bothering to argue whether worms can learn, since all agree that mice and rats can learn. In addition, everyone agrees that training rats and mice is a genuine laboratory skill, that takes practice, and so they were willing (now) to agree that the same is true for worms. (There's also something else going on, which is that now everyone only cared about the mammalian experiments.)

McConnell (Mr. Worm) was a psychologist. He was interested in what his experiments could tell him about how memory influences behavior. Ungar was a biochemist. He wanted to find the molecule responsible for memory. He prepared extracts, his experiments required thousands of mice, and hence a psychology lab, and a biochemistry lab, with all sorts of expensive equipment. Immediate result: no more high-school students, and, indeed, almost no one else working on related projects.

Ungar eventually extracted "Scotophobin" an RNA-like molecule that he claimed produces "memories" of light paired with shock in mice.

At each stage of the story, some labs try to replicate the results, and most, but not all succeed, and several times, it is labs of the most reputable scientists who fail.

At around this time, someone discovers that polypeptides (which are a lot cheaper, more stable, and easier to synthesize than "Scotophobin") are active in the brain, you can extract different ones from different areas in the brain, injecting different ones cause distinguishable differences in behavior. The lab failing to replicate Ungar's results then says, it isn't Scotophobin, it must be a polypeptide. And everyone forgets the whole subject and works with polypeptides for the next 20 years, and no one has ever gone back.

The research program was degenerative, and it got replaced by a new paradigm.

-- ShaughanLavine - 14 Nov 2005