Shufflebrain

It's not that a structuralist cannot answer such a question. But the structuralist's thesis--my old argument--must be tied together with an embarrassingly long string of maybes.

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The mind-brain conundrum has many other dimensions and extends to virtually every level of organization and discourse, from molecules to societies of animals, from molecular biophysics to social psychology. Name the molecule, cell, or lobe, or stipulate the physiological, chemical, or physical mechanism, and somebody, someplace, has found memory on, in, around, or associated with it. And, in spite of the generally good to splendid quality of such research, there's probably someone else, somewhere, whose experiments categorically deny any given conclusion or contradict any particular result.

Among those who believe, as I did, that memory is molecular, there are the protein people, the RNA people, the DNA people, the lipid people. And they're often very unkind to each other. Why? Most scientists, consciously or unconsciously, practice the principle of causality--every cause must have one and only one effect, or a causal relationship hasn't been established. If you are an RNA person and somebody finds memory on fat, that's unpleasant news. For RNA and fat cannot both be the cause of memory.

Some investigators believe that memories can be transferred from animal to animal in chemical form; that it's possible to train a rat, homogenize its brain, extract this or that chemical, and inject the donor's thought into another rat or even a hamster. The disbelievers vastly outnumber the believers, for a variety of rational and irrational reasons. Not everyone has been able to reproduce the results;[6] but memory transfer is in the literature, implicating quite a variety of alleged transfer substances.

Some research on memory does not implicate molecules at all. And while some data suggest that memories depend on reverberating circuits to and from vast regions of the brain, other evidence places memory in individual cells.

Who's right? Who's wrong? As we shall see later in the book, this is not the question.

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Dynamics of the learning process have suggested to psychologists that two distinct classes of memory exist: short-term memory and long-term memory. Short-term memory is, for example, using the telephone number you look up in the directory and forgetting it after you have put through the call. Long-term memory operates in the recollection of the date of New Year's, or in remembering the telephone number, you don't have to look up. Can we find any physiological evidence to support the psychologists' claim? The reader probably knows that electroconvulsive shock (ECS) can induce amnesia. ECS can totally and permanently obliterate all signs of short-term memory, while producing only temporary effects on long-term memory.[7] Certain drugs also induce convulsions with results very similar to those produced in experiments with ECS. Taken together, the evidence does indicate that short-term memory and long-term memory depend on different physiological mechanisms.

Some investigators employ a very interesting theory in dealing with the two classes of memory.[8] According to this theory, short-term memory is the active, working memory, and it exists in an idealized "compartment." Long-term memory is stored memory, and the storage "depot" differs from the working compartment. According to the theory, the working compartment receives incoming perceptual data, which create short-term memories. The short-term memories, in turn, make the long-term memories. In other words, in the learning process, information from experience moves into the working compartment, becomes short-term memory, and then goes on to the storage depot. But what good would the memory be if it were confined to storage? According to the theory, the working compartment has two-way communication with the storage depot. In this theory, when we use long-term memory, we in effect create a short-term working memory from it. And there's more. Learning doesn't depend simply on what comes into the mind. The remembered past has a profound effect on what we're learning in the present. Cognition--understanding--can't be divorced from the learning process. The working-memory theory maintains that the active memory in the working compartment is a blend of perception from the senses and memory drawn from storage. When we forget, the active memory "goes off" in the working compartment.

But the concept of two classes of memory gives rise to imponderables in the mind-brain connection. If different physiological mechanisms handle short-term and long-term memories, how do we explain their informational identities? After all, Butterfield 8 is Butterfield 8 whether we forget it immediately or remember it to the end of our days. There are other problems. The useful working-memory theory requires a more general theory to link it to reality.

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