consciousness

I've just finished Mary Roach's entertaining book, Spook: Science Tackles the Afterlife.

I haven't read Roach's previous book, Stiff, which explores some of the odd things that happen to cadavers after people die. Being an anthropologist, I guess I know about as much about that topic as any reasonable person could want.

But I recently saw a really interesting documentary about Harry Houdini, focusing on his other career: debunking mediums. Flipping through Spook in the bookstore, it looked like a good chance to follow up on the subject. The book didn't disappoint, and broadened beyond the spiritualism movement to describe other loopy ideas about the afterlife.

For instance, did you ever wonder why they say the soul weighs 21 grams? Roach describes the 1901 experiment, in which physician Duncan MacDougall arranged to have dying tuberculosis patients placed on a giant scale -- reasoning that if their soul belonged to the material world, the weight of the patient would drop at the moment of death. And it did by three-quarters of an ounce.

Roach follows up with a long line of other people who tried to weigh dying animals (whose souls invariably weighed less than humans, and -- unsurprisingly -- generally less than the rated accuracy of their scales). She contacts the historical archives of the Fairbanks scale company, to see if the instrument used by MacDougall was really accurate to a fifth of an ounce (it was, although the necessary modifications to hold a deathbed together with a doctor and stethoscope may have compromised its accuracy).

Early twentieth-century séances were the low-tech equivalent of today's light-and-sound shows. The medium darkened the lights (because naturally, light interferes with messages from the spirit world). Then a variety of hijinks would ensue. Often the table would mysteriously rise -- mysteriously because the medium's hands were being held by other people. A bell might ring to signal the presence of a spirit. "Spirit voices" would start echoing around the room.

The most dramatic highlight of a séance was the sudden, unexplained appearance of a mysterious substance called ectoplasm, draped over the medium. Now, if you -- like me -- are a member of the Ghostbusters generation, you probably imagine ectoplasm as a goopy, mucous-like substance that mainly plops onto people whose bodies run through a ghost.

But 1920's-era mediums didn't have Industrial Light and Magic to design their special effects. So real ectoplasm didn't generally look like mucus. It looked a lot more like damp cloth.

Because, well, generally it was damp cloth. Damp because the medium often pulled it out of her vagina. Cloth because sheep mesenchyme and other more exotic organic materials were harder to get a hold of, and were probably much less pleasant to swallow and regurgitate on demand.

Oh, yeah. The upper crust of 1920's society was sitting around tables in dark rooms, waiting for doctors' wives and other less savory characters to pull sheep innards out of their orifices. And we worry about kids watching too much TV. I've got to tell you, the Scooby Doo gang would never be fooled by this stuff!

Roach has what I would call a "bloggy" writing style, full of non sequiturs, set-ups for later jokes, and wonky footnotes. This may put you off -- even I found that the style sometimes wore thin. The style works best for the lighter subjects of séances, ghost hunting, and soul weighing. It was perfect for the section where Roach herself visits a "boot camp" for wannabe mediums. It seemed too glib in the sections dealing with more current research, including psychologists studying near-death experiences in cardiac patients and the historical case where a will was contested based on the appearance of a ghost.

The first chapter in particular struck a discordant note compared to the rest of the book. Roach accompanies a researcher into rural India, where he is investigating claims of reincarnation. It is the least entertaining of the sections -- Roach's observations of the people and place are a bit over-snarky for what seems to deserve a more serious treatment. I would have put this section toward the end of the book, where Roach covers other more current efforts to research the afterlife. It would have made a nice comparison with the out-of-body experience research, which boils down to a high-tech version of the same question: Are people really describing the same thing, and do they have any information that could prove it?

Still, it helps to remind us that modern-day scientists are as almost as strange to their local cab drivers and other ordinary people as 1920's spiritualists must have seemed. And frankly, some of the modern "scientists" really are batty. In my opinion, there's nothing disreputable about end-of-life research, or research into the effects of infrasound on conscious perceptions. But when people descend to talk about quantum effects on the brain and microtubules, it doesn't matter what they say, they are making it all up.

In fact, I would say that quantum effects are the new ectoplasm. Say a few mumbo-jumbo words, claim that modern-day scientists are suppressing investigation of a world that they cannot imagine, and do it all with a lot of conviction. It is no less true of Roger Penrose's quantum microtubule ideas about consciousness then it is of any of the examples in Spook. One of the high notes of the book is the way it shows that anyone can be taken in by the right words, spoken in the right tone of voice.

I like this post on octopus intelligence by Chris Chatham. He reviews an article by Jennifer Mather that claims that cephalopods have primary consciousness. Here is the article's abstract:

Behavioural evidence suggests that cephalopod molluscs may have a form of primary consciousness. First, the linkage of brain to behaviour seen in lateralization, sleep and through a developmental context is similar to that of mammals and birds. Second, cephalopods, especially octopuses, are heavily dependent on learning in response to both visual and tactile cues, and may have domain generality and form simple concepts. Third, these animals are aware of their position, both within themselves and in larger space, including having a working memory of foraging areas in the recent past. Thus if using a 'global workspace' which evaluates memory input and focuses attention is the criterion, cephalopods appear to have primary consciousness.

Chatham's post summarizes the main points made in the article, it's a good place to start. For example, this point about sociality and communication in squid is illuminating:

Octopus performance on traditional behavioral tests of theory of mind is difficult to evaluate, since octopi are primarily solitary animals. The classic "mirror test" of consciousness is also inconclusive since octopi seem relatively unreliant on vision. Squid, on the other hand, are more social animals and are apparently more reliant on vision (considering they have relatively sophisticated real-time control of the pigmentation of their skin. Some have proposed that these two feature might permit for the emergence of language among squid. Sure enough, patterns of skin pigmentation have been to have a lexical but not grammatical communicative structure (i.e., skin color seems to convey detailed information about current sexual or emotional states, without seeming to have a rule-like structure for how those signals can be combined).

The main reason for an anthropologist to be interested in cephalopod cognition is that their brains evolved largely independently from ours. The common ancestor of vertebrates and cephalopods had nothing like the neural complexity and brain anatomy of either mammals or cephalopods, so most shared functional capacities in these animals must be convergent. As the review notes, there are both functional and anatomical convergences, and the question is to what extent the form and function are related. Many of the genes that determine neural development in these lineages are shared from their common ancestor, so there is also an interesting question about the extent that genetic homology may predispose descendant lineages to functional and anatomical convergences.

I think I'll include this article on my reading list next time I offer Biology of Mind (which should be fall 2008, for students who may be wondering).

References:

Mather JA. 2007. Cephalopod consciousness: behavioural evidence. Consciousness and Cognition (in press) doi:10.1016/j.concog.2006.11.006

Philosopher of mind John Searle has written a review of Nick Humphrey's new book, "Seeing Red: A Study in Consciousness."

He doesn't much care for the book's hypothesis about the nature of consciousness, which involves the idea that sensation (roughly, qualia by another name) is separate and parallel to perception.

In a word toward explaining the quote below, the review uses a recurrent metaphor throughout. Searle proposes that Humphrey has attempted to set mind and brain equal to each other, in the form of an equation. But like any equality in physical science, this exercise requires that the measurement units be made the same on both sides of the equation. In Searle's view, this is where the book is misguided -- Searle claims that we should be looking for not an equality of mind and brain, but instead a causal account of how the physical brain gives rise to mind.

The problem with the equation mode of thinking:

The enterprise was bound to fail because the equation does not solve the problem; it presupposes that the problem has already been solved. The problem is to explain the relation of consciousness to brain processes, specifically to explain how brain processes cause (give rise to, produce, bring about) qualitative subjectivity. We already have qualitative subjectivity on the left-hand, mind, side of the equation, by definition. The question then is: How does it get into the right-hand or brain side? But that is precisely the mind-body problem, the problem that the equation was supposed to solve. Humphrey does not address that question directly; rather, he changes the subject. Our question is: How do objective third-person brain processes right here and now (as well as in earlier evolutionary times) cause our conscious states? What specific parts of brain anatomy do it and how do they work? His question is: Assuming that perception is unconscious, how might conscious sensations have evolved and what functions would they perform? His answer, in brief summary, is that they evolved by monitoring our responses to input stimuli and they function to give us a sense of "the Self." I think he is wrong to separate perception from consciousness; all the same, some evolutionary story about consciousness must be right. But whatever evolutionary story may be proposed is an answer to a different question from the causal question. The only part of his account that even hints at an answer to the causal question is the discussion of feedback mechanisms. But he does not tell us how we get from the feedback mechanisms to qualitative subjectivity.

I italicized the first sentence here because it strikes me as very useful -- one could for example make the same observation about Daniel Dennett's "Cartesian theater" account of consciousness. The problem is that if your theory asserts that the "problem" of mind is not really a problem, because mind just is some aspect of brain physiology, then you really are just presupposing that the problem has already been solved, rather than actually proposing some solution.

Searle is, as he often has been, a persuasive proponent of the idea that consciousness remains to be explained.