mind

Dienekes points to a study by Marieke van Leeuwen and colleagues, in which they assess the phenotypic correlation between IQ and brain volume in a sample of 9-year-old children. The correlation overall is between 0.2 and 0.33 for different components of brain volume, consistent with earlier studies of adults based on MRI scanning.

What interested me about the paper was the last sentence of the abstract:

The relation between brain volume and intelligence was entirely explained by a common set of genes influencing both sets of phenotypes.

which seems quite interesting if true. The paper involved a comparison of the phenotypic correlations in sets identical and fraternal twins, allowing an estimate of the genetic correlation of the traits.

Table 7 shows the genetic and environmental correlations, below and above the diagonal, respectively. Amongst brain measures the genetic as well as the environmental correlations are significant, showing that correlations between genetic and environmental factors both contribute to the phenotypic correlations amongst the three brain measures. The same applies for the phenotypic correlations between PO [perceptual organization] and g [the general factor of IQ], and PO and VC [vocabulary and comprehension, another part of the IQ test]; common genetic as well environmental factors contribute to the phenotypic correlations between these intelligence measures.

In other words, when it comes to the correlations within the different components of brain volume, and within different parts of the test battery, environmental correlations and genetic correlations were both important.

In contrast, the phenotypic correlations between brain and intelligence measures and among intelligence measures are explained by correlations between genetic factors only.

The different values for genetic correlations of test and brain volume variables gives them some ability to test one causal hypothesis:

If intelligence causally influences brain volumes, this would also be reflected in the genetic and environmental correlations: all genetic and environmental factors that influence intelligence would, through the causal chain, influence brain volume. However, our study shows that only the genetic correlations are significant. In fact 85% to 100% of the covariation between brain volume and intelligence are caused by shared genetic factors. This leaves two options: 1) the relation between brain volume and intelligence is caused by a set of genes which influences variation in brain volume and this variation in turn leads to variation in intelligence 2) pleiotropy: there is a set of genes which influence brain volume as well as intelligence.

The discarded hypothesis is, unfortunately, the least credible of the three alternatives anyway, unless you think that higher IQ actually inflates the volumes of people's brains.

The paper could be more clear about the nature of the "common" genetic variants -- what it means is that the genes are held in common between the two phenotypes, not that they have found common genes. That leaves the nature of the actual genetics of the traits completely open (e.g., rare familial variants versus high-frequency variants, regulatory vs. coding, etc.). They do list a number of examples of possible genes (focusing on myelination as a process that might affect both phenotypes), but these are entirely speculative, and not really worth going into at this level.

What is more interesting is the possibility that the genetic correlations mainly arise from early postnatal development:

Possibly, these genetic factors come into play already early in development. Gale, O'Callaghan, Bredow, and Martyn (2006) and Gale, O'Callaghan, Godfrey, Law, and Martyn (2004) showed – measuring head circumference – that brain growth during infancy predicts intelligence in eight- and nine-years-olds, while brain size at birth and brain growth later in life is not associated with intelligence in both these age groups. After infancy children could not compensate for poor brain growth earlier in life. This shows that the relation between brain volume and intelligence already is established between birth and one year of age (van Leeuwen et al. 2008:8).

This is worth further study since the initial postnatal brain growth period and rate have plausibly changed during human evolution. The timing and rate of developmental effects during this time (also very important to linguistic and other cognitive developments) could have been targets of selection in the past.

Also, modularization (or demodularization) of these genetic networks might have influenced pleiotropies between the disadvantages of larger brains (in developmental and energetic terms) and the advantages of learning.

References:

van Leeuwen M, Peper JS, van den Berg SM, Brouwer RM, Hulshoff Pol HE, Kahn RS, Boomsma DI. 2008. A genetic analysis of brain volumes and IQ in children. Intelligence (in press) doi:10.1016/j.intell.2008.10.005

A man known to most psychologists only as H. M. has died. Benedict Carey has the story. After a brain operation to relieve profound seizures, H. M. was left with a complete inability to form new declarative memories. And his condition led to a revolution in the science of memory itself:

At the time, many scientists believed that memory was widely distributed throughout the brain and not dependent on any one neural organ or region. Brain lesions, either from surgery or accidents, altered people’s memory in ways that were not easily predictable. Even as Dr. Milner published her results, many researchers attributed H. M.’s deficits to other factors, like general trauma from his seizures or some unrecognized damage.

“It was hard for people to believe that it was all due” to the excisions from the surgery, Dr. Milner said.

That began to change in 1962, when Dr. Milner presented a landmark study in which she and H. M. demonstrated that a part of his memory was fully intact. In a series of trials, she had Mr. Molaison try to trace a line between two outlines of a five-point star, one inside the other, while watching his hand and the star in a mirror. The task is difficult for anyone to master at first.

Every time H. M. performed the task, it struck him as an entirely new experience. He had no memory of doing it before. Yet with practice he became proficient. “At one point he said to me, after many of these trials, ‘Huh, this was easier than I thought it would be,’ ” Dr. Milner said.

The implications were enormous. Scientists saw that there were at least two systems in the brain for creating new memories.

Behavioral science depends so completely on the willingness of subjects to volunteer for analysis and study. But rarely has so much understanding been achieved upon the cooperation of a single person.

The ability to interpret others' mental states and intentions, called "Theory of Mind," has been a key area of interest for those studying the evolution of primate and human social behavior. Often, people have imagined that Theory of Mind emerges as a correlate of self-awareness -- the ability to reflect on one's own mental states. As the model goes, a focal individual interprets another's mental state by imagining herself "in the shoes of" the other individual.

Well, this week's Science has a short paper by R. Shayna Rosenbaum and colleagues that presents evidence that the "in their shoes" model is wrong. First a mini-review of why you would believe the usual idea in the first place:

The idea that ToM is closely related to, and that it may depend on, episodic memory and autonoetic consciousness seems perfectly natural: that in order to imagine and make sense of other people's thoughts, feelings, intentions, and actions, we must rely on our autobiographical recollections (1). The ability to consciously recollect past personal happenings has been shown to be necessary for imagining coherent and detailed personal happenings in the future (2, 3). Both episodic memory and ToM emerge close in time in ontogenetic development (4). The neural substrate on which the two abilities rely is in many ways strikingly similar (1).

But they examined two patients with brain injuries that eliminated personal episodic memory. In both cases, the patients showed an ability to interpret the mental states of other individuals, even though they could not imagine future events in their own perspective:

The current findings are at variance with the idea that the ability to simulate or reconstruct one's own past mental states is necessary to imagine the contents of other people's minds (1, 2). Both K. C. and M. L. suffer from severe difficulties in consciously (autonoetically) recollecting any events from any period of their lives. Yet they have no apparent difficulty in taking other persons' perspectives and inferring other people's thoughts, feelings, and intentions, as revealed by the ToM tests. The findings imply that K. C.'s and M. L.'s ToM ability may depend on semantic memory and general knowledge abilities that are largely preserved in both cases (5, 6).

This may go along with last week's paper by Hamlin, Wynn and Bloom, which showed that infants develop an ability to evaluate others' intentions much earlier than had been thought:

Here we show that 6- and 10-month-old infants take into account an individual's actions towards others in evaluating that individual as appealing or aversive: infants prefer an individual who helps another to one who hinders another, prefer a helping individual to a neutral individual, and prefer a neutral individual to a hindering individual. These findings constitute evidence that preverbal infants assess individuals on the basis of their behaviour towards others.

This isn't quite the same as Theory of Mind -- the infants are getting a general idea of whether a person is nice, not evaluating specific intentions. But the study of the individuals who lack episodic memory suggested that they were using more general cognitive resources to enable their interpretation of others' intentions. That would presumably include the kinds of heuristics that these babies were developing to judge people as "helpers" or "hinderers".

It may be that Theory of Mind is built from exactly the kind of simple observations that the babies can use, and that rather than build a detailed "simulacrum" of another person's intentions, we can interpret their likely intentions based on general knowledge of what people are likely to do based on similar external signs. That kind of skill might vary quantitatively among primate species, and provides a possible evolutionary pathway for this important social ability.

References:

Hamlin JK, Wynn K, Bloom P. 2007. Social evaluation by preverbal infants. Nature 450:557-559. doi:10.1038/nature06288

Rosenbaum RS, Stuss DT, Levine B, Tulving E. 2007. Theory of mind is independent of episodic memory. Science 318:1257. doi:10.1126/science.1148763

We've been watching this show on the SciFi channel, Mind Control, in which British "psychological illusionist" Derren Brown. Brown is sort of like a much less skeevy Criss Angel. Not that much less skeevy -- Brown is best-known for playing Russian roulette on TV. And like every aspiring mentalist, he's mastered that eyes-focused-somewhere-inside-your-skin look.

To tell you the truth, the show comes on after Flash Gordon, and, well, I'm a committed Flash Gordon nut.

Anyway, the beauty of the show is that Brown lets you in on the trick, at least some of the time, since the "trick" is really just the power of suggestion. With a highly rehearsed script including repeated cues, he can make people forget what they were thinking before, and to think what he wants instead.

I'm totally going to try this on my classes! Look out, students. Especially on evaluation day....

So in today's science section, the NY Times has a story by George Johnson, who got to sit in on Magic Day at the Consciousness meetings. It sounds pretty cool:

After two days of presentations by scientists and philosophers speculating on how the mind construes, and misconstrues, reality, we were hearing from the pros: James (The Amazing) Randi, Johnny Thompson (The Great Tomsoni), Mac King and Teller -- magicians who had intuitively mastered some of the lessons being learned in the laboratory about the limits of cognition and attention.

"This wasn't just a group of world-class performers," said Susana Martinez-Conde, a scientist at the Barrow Neurological Institute in Phoenix who studies optical illusions and what they say about the brain. "They were hand-picked because of their specific interest in the cognitive principles underlying the magic."

Page 2 of the story gums its way into the confusing topic of qualia. Now, Qualia Day in my biology of mind course would be a good one to try out the mind control -- that is, on the students who really can't be convinced that philosophy is fun.

This is a problem that's big and little at the same time -- from a certain perspective, nothing seems more central than qualia, and yet that centrality seems to have no observable effect on anything else. It's hard to avoid though -- because if you're going to discuss the mind from an evolutionary perspective, you have to lay out what kinds of things evolutionary biology is well-placed to explain. "Qualia" are among the few things that aren't (necessarily) on that list.

So stick to the front page if you're not interested -- and the last half of page 3, where the Amazing Randi gets a few words:

"Allow people to make assumptions and they will come away absolutely convinced that assumption was correct and that it represents fact," Mr. Randi said. "It's not necessarily so."

That's one of the reasons we used to love Jonathan Creek -- at least, until they got rid of Maddie. If your perception can be snookered by assumptions, then your logic can easily go with it.

The beauty of magic is that you know it's not possible, and yet your senses believe it anyway.

[Teller] left us with his definition of magic: "The theatrical linking of a cause with an effect that has no basis in physical reality, but that -- in our hearts -- ought to."

What's more amazing? That these scientists got a show from some of the best non-skeevy magicians in Vegas? Or that Teller talks?

A couple of months ago, Seed magazine ran a conversation between singer/songwriter David Byrne (of the Talking Heads) and cognitive music researcher Daniel Levitin. It's a really interesting mix of topics, and reading David Byrne's thoughts on ideas like mirror neurons and exaptation is pretty remarkable.

DB: So when you watch a performance, sports for example, you're not only watching somebody else do it. In a neurological kind of way, you're experiencing it.

DL:Yeah, exactly. And when you see a musician, especially if you're a musician yourself--

DB: --air guitar.

DL: Air guitar, right! And you can't turn it off -- it's without your conscious awareness. So mirror neurons seem to have played a very important role in the evolution of the species because we can learn by watching, rather than having to actually figure it out step-by-step.

I noticed that Levitin seemed to be doing more and more of the talking as the conversation went on, but he makes it a good introduction to some current thinking on the evolution of musical ability and cognition.

The Sunday NY Times is carrying a very long article about Williams syndrome by David Dobbs. I think it's a nice article, beginning with some anecdotes relating the lives of people with Williams, and then proceeding into the science:

After being ignored for almost three decades, Williams has recently become one of the most energetically researched neurodevelopmental disability after autism, and it is producing more compelling insights. Autism, for starters, is a highly diverse “spectrum disorder” with ill-defined borders, no identified mechanism and no clearly delineated genetic basis. Williams, in contrast, arises from a known genetic cause and produces a predictable set of traits and behaviors. It is “an experiment of nature,” as the title of one paper puts it, perfect for studying not just how genes create intelligence and sociability but also how our powers of thought combine with our desire to bond to create complex social behavior — a huge arena of interaction that largely determines our fates.

Also, the story of J. C. P. Williams himself presents an unsolved mystery:

Williams syndrome was first identified in 1961 by Dr. J. C. P. Williams of New Zealand. Williams, a cardiologist at Greenlane Hospital in Auckland, noticed that a number of the hospital’s young cardiac patients were small in stature, had elfin facial features and seemed friendly but in some ways were mentally slow. His published delineation of this syndrome put Dr. Williams on the map — off which he promptly and mysteriously fell. Twice offered a position at the prestigious Mayo Clinic in Rochester, Minn., he twice failed to show, disappearing the second time, in the late ’60s, from London, his last known location, with the only trace an unclaimed suitcase later found in a luggage office.

Wow, that's weird. I couldn't find any more details on the disappearance.

Doesn't that pretty much sum up the message of these two paragraphs in this NY Times article

Charles Darwin, author of the revolutionary "Origin of Species," was the fifth of six children. Nicolaus Copernicus, the Polish astronomer who determined that the Sun, not the Earth, was the center of the planetary system, grew up the youngest of four. René Descartes, the youngest of three, was a key figure in the scientific revolution of the 16th century.

First-borns have won more Nobel Prizes in science than younger siblings, but often by advancing current understanding, rather than overturning it, Dr. Sulloway argued. "It's the difference between every-year or every-decade creativity and every-century creativity," he said, "between creativity and radical innovation."

Or, "Sure, also-borns, you gave us Darwin and Descartes, but what have you done for us lately?"

I just wish that articles like this were illustrated along with the relevant distributions, showing not only the difference in means (in this case, 3 points) but also the standard deviations and overlap. That would be much more useful than these wiggle-paragraphs at the end.

Also, I wonder if there is some kind of biasing effect here, where parents are more likely to have successive offspring if their first one is healthier, aka smarter. I'll have to see the study to see if they control for this, but if not then the IQ loss in subsequent siblings may partly be regression to the mean.

UPDATE (6/22/2007): The analysis of children whose older siblings died might test for regression to the mean. Second-born children whose older sibling died tended to have IQs approximately the same as first-born children. So the interpretation is that the social rank of the child is the determining factor.

I say "might" because I'm not convinced this comparison tests for regression to the mean. We'd like to know what actual only children look like in comparison to first-borns of larger families. The Science paper doesn't specifically address the issue, but the comparison of first-born and second-born after death of first-born is very suggestive.

References:

Kristenen P, Bjerkedal T. 2007. Explaining the relation between birth older and intelligence. Science 316:1717. doi:10.1126/science.1141493

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

Nicholas Wade writes about primate behavior as a model for human morality. The article is mostly a profile of Frans de Waal's work.

Dr. de Waal sees human morality as having grown out of primate sociality, but with two extra levels of sophistication. People enforce their society's moral codes much more rigorously with rewards, punishments and reputation building. They also apply a degree of judgment and reason, for which there are no parallels in animals.

Religion can be seen as another special ingredient of human societies, though one that emerged thousands of years after morality, in Dr. de Waal's view. There are clear precursors of morality in nonhuman primates, but no precursors of religion. So it seems reasonable to assume that as humans evolved away from chimps, morality emerged first, followed by religion. "I look at religions as recent additions," he said. "Their function may have to do with social life, and enforcement of rules and giving a narrative to them, which is what religions really do."

As Dr. de Waal sees it, human morality may be severely limited by having evolved as a way of banding together against adversaries, with moral restraints being observed only toward the in group, not toward outsiders. "The profound irony is that our noblest achievement -- morality -- has evolutionary ties to our basest behavior -- warfare," he writes. "The sense of community required by the former was provided by the latter."

This is an interesting introduction to the topic, and -- for my Anthro 105 students -- it gives some detail about one of the reasons anthropologists study primate behavior. Several of de Waal's books reward reading on the topic -- the article mentions Priamtes and Philosophers, but I always recommend The Ape and the Sushi Master for its discussion of traditions and culture.

The NY Times writer Benedict Carey has an interesting short article about research into repressed memories. There is a group of researchers who claim that the phenomenon is a cultural construct that emerged very recently:

In a paper posted online in the current issue of the journal Psychological Medicine, a team of psychiatrists and literary scholars reports that it could not find a single account of repressed memory, fictional or not, before the year 1800.

The researchers offered a $1,000 reward last March to anyone who could document such a case in a healthy, lucid person. They posted the challenge in newspapers and on 30 Web sites where the topic might be discussed. None of the responses were convincing, the authors wrote, suggesting that repressed memory is a "culture-bound syndrome" and not a natural process of human memory.

They're saying that the character Madame de Tourvel in Naturally, other researchers dispute the idea -- some even claim to have evidence from ancient Greek literature.

If I have an informed opinion, I've repressed it. But what I find interesting is the idea that a popular literary trends lead scientific research, sometimes to wrong results. It may be hard to rule out that something imagined in fiction could actually happen -- think of the number of people who have tried to find loopholes in special relativity that could lead to faster-than-light travel. There was no science fiction in 1800, but developing ideas about the mind provide their own equivalent.

We know that science can proceed along a false or misleading path for a long time when the cultural biases of the scientists lead research. Fictional plot devices are clever just insofar as people are willing to "suspend disbelief" about them -- which is a function of the readers' cultural biases. So the two combined might make for some interesting history!

I was going to make it a quote of the day, but this column by NYT writer Dennis Overbye is worth reading in full. It's about the march of science against free will:

"If people freak at evolution, etc.," [philosopher of science Michael Silberstein] wrote in an e-mail message, "how much more will they freak if scientists and philosophers tell them they are nothing more than sophisticated meat machines, and is that conclusion now clearly warranted or is it premature?"

As Overbye points out, it's far from a new problem:

That is hardly a new thought. The German philosopher Arthur Schopenhauer said, as Einstein paraphrased it, that "a human can very well do what he wants, but cannot will what he wants."

Einstein, among others, found that a comforting idea. "This knowledge of the non-freedom of the will protects me from losing my good humor and taking much too seriously myself and my fellow humans as acting and judging individuals," he said.

Well, a hopeful fatalism is one of the attractions of a belief in predestination. But personally, I think when quantum physicists start talking about free will, it is just anthropology-envy. Hey, if you want to study human action, then make a proper study of it! You don't need Gödel, for goodness' sake! That's just a way to say, "Harrumph, the ancient experts show us by long proof that the problem of free will lies deep in a paradoxical enigma. Murmpheaoww! Give me another cigar!"

It's like your doctor quoting Galen when he prescribes an antibiotic. Totally irrelevant!

I don't really think that the central metaphysical question here -- is human action something other than deterministic or random? -- is one that most of us worry too much about. Most people who are thinking about "free will" have in mind things like whether SS stormtroopers were responsible for various reprehensible actions, or whether "just following orders" is a valid excuse.

To my mind, if you've gone all the way to the subatomic level to talk about free will, then you've already answered the really important questions. That is, unless you want to posit an "obey-evil-dictator" neutrino!

Anyway, the article presents a good basic-level overview of Libet's experiments and various follow-ons. The problem is when it derails into whether Cretans are liars and other detours. Seth Lloyd is extensively quoted about whether computer laptops have free will of a sort. Well, they probably do, and in the human sense, besides! Who hasn't thought that her own computer is deliberately thwarting it's master's subtle plans? That's probably more evidence than we require to assume that other people have free will!

I can understand why one might object to a human-computer analogy, but a human brain that is a product of evolution must be computer-like in some important ways. The other side of that analogy is that computers are like brains in some important ways.

"Free will" doesn't mean "unpredictable action", after all. If it did, there would be no sense in predicting anything for the coming year. Which is what I'm setting my mind to this morning!

Why else would I start the year with an overly-glib post about an ancient philosophical problem?

I often refer to the "Sherlock Holmes" theory of the mind in my classes; in honor of finals week, I thought I would post the relevant passage from A Study in Scarlet:

"You see," he explained, "I consider that a man's brain originally is like a little empty attic, and you have to stock it with such furniture as you choose. A fool takes in all the lumber of every sort that he comes across, so that the knowledge which might be useful to him gets crowded out, or at best is jumbled up with a lot of other things so that he has a difficulty in laying his hands upon it. Now the skilful workman is very careful indeed as to what he takes into his brain-attic. He will have nothing but the tools which may help him in doing his work, but of these he has a large assortment, and all in the most perfect order. It is a mistake to think that that little room has elastic walls and can distend to any extent. Depend upon it there comes a time when for every addition of knowledge you forget something that you knew before. It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones."

Time has a short article describing the work of risk assessment expert John Adams.

The point, stresses Adams, is that drivers who feel safe may actually increase the risk that they pose to other drivers, bicyclists, pedestrians and their own passengers (while an average of 80% of drivers buckle up, only 68% of their rear-seat passengers do). And risk compensation is hardly confined to the act of driving a car. Think of a trapeze artist, suggests Adams, or a rock climber, motorcyclist or college kid on a hot date. Add some safety equipment to the equation -- a net, rope, helmet or a condom respectively -- and the person may try maneuvers that he or she would otherwise consider foolish. In the case of seat belts, instead of a simple, straightforward reduction in deaths, the end result is actually a more complicated redistribution of risk and fatalities. For the sake of argument, offers Adams, imagine how it might affect the behavior of drivers if a sharp stake were mounted in the middle of the steering wheel? Or if the bumper were packed with explosives. Perverse, yes, but it certainly provides a vivid example of how a perception of risk could modify behavior.

Adams makes two points:

(1) People who will tolerate a given level of risk will respond to an objective reduction in risk by doing riskier things. (Elsewhere, Adams calls this idea the "risk thermostat" model.)

(2) Risk is interactive and unequally distributed, so that decreasing the risks for one category of individuals may increase it for others.

Car accidents make pretty good illustrations for both. Some people who drive large SUVs feel a greater safety margin and therefore drive more aggressively. Providing these people with a "safer" driving platform tends to increase the risks for drivers of smaller cars. If these effects were strong enough, putting a "safer" class of vehicle on the road would actually increase the overall number of fatalities.

A web search for Adams' work brings up a technical report written for the Cato Institute, discussing risk perception in more detail. After a review of the effect of seat belt laws, he embarks on a discussion of risks identified through science. These kinds of risks are not directly accessible to the senses, and their magnitude can be appreciated only by studying large populations of things. The long-term risk of smoking is one example.

Before discussing these kinds of risks, Adams considers our attitudes toward risks that are accessible to the senses:

Directly perceptible risks are "managed" instinctively; our ability to cope with them has been built into us by evolution--contemplation of animal behavior suggests that it has evolved in nonhuman species as well. Our method of coping is also intuitive; we do not do a formal probabilistic risk assessment before we cross the street. There is now abundant evidence, particularly with respect to directly perceived risks on the road, that risk compensation accompanies the introduction of safety measures that do not reduce people's propensity to take risks. Statistics for death by accident and violence, perhaps the best available aggregate indicator of the way in which societies cope with directly perceived risk, display a stubborn resistance, over many decades, to the efforts of safety regulators to reduce them (Adams 1999:10).

Adams notes that much of the decrease in premature mortality during the past 150 years has been brought about by better understanding and communicating about invisible risks. The germ theory of disease is probably the most notable example.

But he points out the difficulty of measuring reductions in risk. At least, we can measure overall mortality rates -- if they decline after an intervention, then presumably it was effective. But activity-specific mortality rates won't do:

Moreover, risks can be displaced. If motorcycling were to be banned in Britain it would save about 500 lives a year. Or would it? If it could be assumed that all the banned motorcyclists would sit at home drinking tea, one could simply subtract motorcycle accident fatalities from the total annual road accident death toll. But at least some frustrated motorcyclists would buy old clunkers and try to drive them in a way that pumped as much adrenaline as their motorcycling did, and in a way likely to produce more kinetic energy to be dispersed if they crashed. The alternative risk-taking activities that they might pursue range from skydiving to glue sniffing, and there is no set of statistics that could prove that the country had been made safer, or more dangerous, by the ban (Adams 1999:20).

Now, I'm reading this because I'm evaluating strategies toward risk in human evolution. Mortality reductions are a major trend in the emergence of modern humans. That would tend to indicate an objective decrease in risks of various kinds.

But a decrease in mortality risk may not translate to an increase in fitness. For instance, if more adult males survive to older ages, they may prevent younger males from reproducing until they are older. If this happened, a reduction in mortality would impose a tradeoff of a reduction in fecundity for younger individuals. This tradeoff would not prevent the change, by any means -- in the transient after the appearance of a risk-reducing strategy, males who adopted the strategy would immediately have a fitness benefit. But the tradeoff itself might obscure the reasons for the change, or even suggest wrong hypotheses (for instance, the hypothesis that low fecundity for young males forced them to reduce their mortality risk).

Anyway, if professional statisticians are so bad at evaluating the risk landscape, evolutionary biologists are no better. Many evolutionary hypotheses deal explicitly in risks -- with increases in some risks being explained by declines in others. But if you have ever seen an attempt to quantify those risks in terms of fitness, you probably understand how shaky the foundations of such hypotheses can be.

This is the beginning of a multipart series on evolution and risk. There will be some math involved -- calculus, even! -- but at the end something very important will emerge. Risk is the hinge connecting the evolution of human life histories to the evolution of the human brain.

It's not here, but at Brainethics, where Martin Skov has written up a short intro to the evolution of aesthetics with a booklist from the recent literature.

Neuroaesthetics can be thought of as a part of a more general study of art and aesthetics as a biological phenomenon. I will follow other proponents of this view (such as Tecumseh Fitch) in calling this broader approach bioaesthetics. The overall goal of bioaesthetics is to answer the three basic biological questions - what?, how?, why? - in regard to aesthetic behaviour in humans: what is art and aesthetics?; how does art and aesthetics spring from the brain?; and why did this cognitive ability evolve in humans? Neuroaesthetics is predominantly concerned with question number 2. In the list that follows below I will also mention a number of books that discuss the other two questions.

If you are one of my students and this area interests you, this is as good a list of recent books on the topic as you will find.

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.

Earlier this week, a Japanese man recited the first 100,000 decimal digits of pi:

Akira Haraguchi, 60, needed more than 16 hours to recite the number to 100,000 decimal places, breaking his personal best of 83,431 digits set in 1995, his office said Wednesday. He made the attempt at a public hall in Kisarazu, just east of Tokyo.

As if to show just how difficult that would be, the ABC News story makes an obvious rounding error on digit four:

It is usually written out to a maximum of three decimal places, as 3.141, in math textbooks.

That would be one bad math textbook!

Anyway, this kind of extreme memory feat certainly shows the capability of some people to accommodate their minds to highly specialized information strings. Memorizing the complete works of Shakespeare, the full Koran and other long texts are other examples.

For a little entertainment, and an interesting perspective on the nature of cognition and scientific reasoning, I suggest this clever essay by Jonah Lehrer of Seed:

[Emily] Pronin's experiment was simple: Harvard students were shown a voodoo doll and told that they were part of a study of "physical health symptoms that result from psychological factors...in the context of Haitian Voodoo." (In fact, dolls are not used in Haitian Voodoo but "they were used here to conform to participants' expectations about Voodoo practice.") Unbeknownst to the volunteers, the scientists had recruited a "confederate" as part of their experimental design. The confederate dressed and behaved normally with half of the participants - and very badly with the other half. He arrived late, tossed an extra copy of a consent form toward the trash can, but missed and left it on the floor. While the subjects read the voodoo death article, "he slowly rotated his pen on the tabletop, making a noise just noticeable enough to be grating." In other words, he acted like he deserved a hex.

You'll have to read it to see how it turned out.

It's an interesting study in the psychology of cause-and-effect, which figures not only into the area of scientific reasoning (as it is applied here) but also in the construction of memory.

A number of studies lately have focused on the way that people "fabulate" their memories. It seems that people don't remember the way things actually happened. Instead, they reconstruct a narrative about them based on the things that they do remember. Since these facts are often sketchy, the narrative begins to diverge from reality.

This phenomenon accounts for why different participants in an event usually remember it differently. It also lies at the root of the issue of false "recovered" memories -- since it can be easy to get someone to reconstruct events wrongly, yet vividly, by suggesting to them a few errant facts.

When people reconstruct the course of an event, they do so using knowledge and principles that their minds apply broadly to many kinds of things. In a sense, this process of constructing "causation" is one that is fundamental to our cognitive life. It works just to the extent that the causes we imagine are compatible with reality.

Is voodoo compatible? Well, in the experimental setup, there isn't a way to test whether the hex was real...

I was reading this Wired article about DARPA research on visual perception...

A new brain-computer-interface technology could turn our brains into automatic image-identifying machines that operate faster than human consciousness.

Researchers at Columbia University are combining the processing power of the human brain with computer vision to develop a novel device that will allow people to search through images ten times faster than they can on their own.

...and thinking, "Gee, wouldn't this be handy for research":

The brain emits a signal as soon as it sees something interesting, and that "aha" signal can be detected by an electroencephalogram, or EEG cap. While users sift through streaming images or video footage, the technology tags the images that elicit a signal, and ranks them in order of the strength of the neural signatures. Afterwards, the user can examine only the information that their brains identified as important, instead of wading through thousands of images.

You know, if it could automatically highlight interesting parts of papers. And then search through other papers for similar passages by keywords. And spring them all up on a really big screen. And put them all in the bibliography automatically.

Or maybe you'd just connect all the links to your own paper at the end, and call it a "brainiography".

Just think how insulted your colleagues would be if they didn't make it in!

I guess the next logical step would be tracking the "aha" signals for peer review...