Wait a minute, shouldn’t that header say “A smiling face”? No; voices can show a smile too. Researchers videotaped test subjects who were answering questions in an increasingly silly interview, and identified on the videotape four different levels of smile, ranging from no smile at all to a full-out grin. Then people who hadn’t seen the video were given just the audio portion to listen to, and it turned out that they were pretty good at identifying the different types of smiles just from characteristics of the voice. Voice communication has emoticons beat when it comes to conveying subtle nuances of emotion, and this is a good example of that. This article from Science Daily has more information.
Plate tectonics and life
The American Astronomical Society is holding its annual meeting in Austin, so you might notice that Thinking Meat is taking on a definitely star-struck feel this week. A story that made the news today is about plate tectonics on Earth-like planets.
The processes of plate tectonics are believed to be responsible for some crucial features that make Earth habitable, including the cycling of carbon dioxide between rock and atmosphere and back again (essential for temperature control, which in turn is essential for maintaining liquid water on the surface). Not to mention the creation of the continents and the maintenance of the magnetic field that helps keep our planet from being pasteurized by cosmic radiation—plate tectonics are good for living things. (Peter Ward and Donald Brownlee spend a whole chapter on plate tectonics in their book Rare Earth: Why Complex Life Is Uncommon in the Universe.)
But the news from Austin is that Earth appears to be at the small end of the range for planets with suitable conditions for plate tectonics. Simulations of rocky planets much larger than Earth showed that the movements of continental plates become easier on bigger planets, where the plates are thinner. Based on the simulations, scientists would expect to find plate tectonics operating on rocky planets three times as massive as the Earth and larger (with an upper limit of about ten times the Earth’s mass, because any bigger than that planets start to turn into gas giants). Perhaps the presence of water on Earth adds enough subterranean pressure to get the plates moving even though our planet is so small. Note that Mars and Venus, both smaller than Earth, do not have plate tectonics, and as far as we know have no life, certainly no complex life. It looks like rocky “super-Earth” planets might be relatively common in the cosmos, which makes this good news for anyone who hopes to someday find evidence for extraterrestrial life.
However, it’s a little disconcerting to realize that Earth is somewhat marginal in the plate tectonics department, especially in light of another news story about how the process might occasionally quit working. Geochemical evidence suggests that about a billion years ago, the volcanism associated with plate tectonics stopped. Around the same time, an ocean basin closed and the subduction zones surrounding it (where rock on the ocean floor collides into continental rock and gets pushed beneath it) were shut down, evidently bringing plate tectonics to a halt. Today subduction, an important driver for volcanism, earthquakes, and associated disturbances, is mostly happening in the Pacific basin, which is predicted to close in about 350 million years, when North and South America run into Eurasia. When this happens, plate tectonics might again grind to a halt (I know that phrase is a cliche, but it seems appropriate for something that involves the collision of continents). So it may be that our planet is not just borderline geologically active, but only intermittently geologically active as well.
Book review: On Deep History and the Brain
On Deep History and the Brain, by Daniel Lord Smail
Berkeley: University of California Press, 2008
When did human history begin? Most general histories pick something like the beginning of the written record, or Mesopotamia. In any event, a date or event is picked before which there is taken to be no human history as we would define it. What we know about how our earlier ancestors lived is described as part of another discipline, perhaps anthropology or paleoarcheology. In On Deep History and the Brain, historian Daniel Lord Smail argues that the choice of a relatively recent date for the start of human history is more or less arbitrary and reflects the structure of an earlier conception of a “sacred history.” He proposes that the entire story of our species be integrated into the narrative of historians. He also offers some exciting suggestions for a possible approach to deep history centered around the human brain and nervous system.
The first two chapters are probably most meaningful to professional historians, but they’re accessible to any reasonably well-educated reader. Smail describes the way an earlier sacred narrative shaped our sense of history, and how vestiges of that narrative still shape our sense of when history began. Historians may reject the story of the garden of Eden, but history is still taken to begin at some base point in the human trajectory—perhaps the earliest farming communities, which contained the seeds of today’s world. Or maybe the fall of the Roman Empire takes the place of the expulsion from the garden, and we begin with the Middle Ages, relatively primitive compared to what came before or after. We still assume there is some starting point at which we open the book onto a human story, rather than recognizing the long gradual process by which we became what we are.
After outlining the history of our view of history, Smail considers and rejects a number of starting points that have been chosen for history. (Many of these arguments are no longer made by historians, but they still form a sort of ghost remnant of ideology that haunts our ideas of history.) He concludes that human societies don’t emerge into history when they start developing a written record, or when they demonstrate a consciousness of their own stories, or when they become politically organized, or when they cross some boundary line (e.g., 4000 B.C.) that separates human from animal societies.
But is there a dividing line inherent in the way humans are able to “transmit their experience to future generations [and] are in some sense the authors of the changes that happen to their societies”? Cultural evolution is Lamarckian, that is, acquired characteristics can be transmitted to others; this is in contrast to Darwinian biological evolution. Cultural evolution thus has an element of human control absent from human biological evolution. Could the advent of cultural evolution offer a justifiable breaking point after which we can legitimately consider human history to have started?
Smail examines this question in the third chapter of the book. He concludes that no, it does not. For one thing, we are not the only animals to have culture, and the cultures of other animals often lack a dimension of intentionality—as early human cultures quite likely did too. So on the far side of the divide, we have culture without much of a guiding hand. On the other side, more recent historical developments are not entirely intentional, but contain elements of chance and blind retention or transmission of changes (which are essential to Darwinian evolution).
He gives an example from his own research, an examination of how written descriptions of property, recorded in various transactions, changed over the later part of the Middle Ages. The parties to a transaction and the notary who recorded their verbal descriptions did not consciously plan to move toward any particular standard system for categorizing the properties, and yet the written descriptions did tend to eventually shift toward such a standard (which might vary from place to place). The shift was probably the result of slight unconscious preferences on the part of the notaries rather than any grand plan or design. In short, the division between Darwinian and Lamarckian factors is blurred rather than clear-cut.
I found the last two chapters to be the most interesting. Although there are many ways to approach a deep history of humankind, Smail proposes one centered around the capabilities and quirks of the human brain. The fourth chapter sketches out this “new neurohistory.”
An important part of this chapter is a critique of evolutionary psychology, which attempts to bring our preliterate past into the study of human societies today. Or rather, I should say it’s a critique of Evolutionary Psychology, although Smail doesn’t use the capitalization to distinguish between the application of evolutionary approaches to human behavior (lowercase evolutionary psychology) and the program laid out by Leda Cosmides, John Tooby, and others (Evolutionary Psychology, or EP). I’m very interested in the former but frequently skeptical of the latter.
When I read a news story about new EP research, I’m often baffled by the leap from the description of a newly identified behavioral trait to the story of why we behave that way. Surely, I think, I must be missing something. There must be something in the paper itself that explains the missing links between the observation of the behavior and the explanation of how it came about. Smail is a historian rather than a psychologist or anthropologist, but his understanding of the process of EP research parallels mine:
“Most work in evolutionary psychology is achieved through the process of reverse engineering—you look at the trait … and then try to imagine the evolutionary context in which it might have been adaptive. It is easy to make mistakes.”
At least I’m not the only observer who thinks imagination plays a key role in the explanatory process.
Smail describes several critiques of Evolutionary Psychology, in particular David Buller’s Adapting Minds: Evolutionary Psychology and the Persistent Quest for Human Nature. Buller makes three relevant arguments: First, natural selection does not homogenize human traits, but produces a diversity of psychological types (not along racial, ethnic, or gender lines, but within populations). I found this the most interesting of his arguments, because I’ve wondered for awhile about whether some personality traits are not adaptive or maladaptive in and of themselves, but might be necessary in balance with other traits within a population.
The second argument is that the human brain is not the product of a set of adaptations to a more or less fixed environment. The social intelligence hypothesis says basically that the development of human intelligence was driven by the need for understanding and relating to our conspecifics; if this is correct, then the shifting social environment gives rise to continuous adaptation of the human brain. The final argument is that the human brain could well have changed in the past 100,000 years rather than being frozen in its response to our ancestral environment.
The rest of the chapter deals with the necessity of taking biology, and in particular neurobiology, into account in history, for example:
“…moods, emotions, and predispositions inherited from the ancestral past, where they evolved at the intersection of human biology and human culture, form a structural backdrop for many things we do and have done. They are interesting for how they tease or suggest. They are also interesting for how they are violated, manipulated, or modulated. And this is precisely where it becomes so important to think with neurohistory. Although the fact is not widely known among historians and is generally overlooked by psychologists and biologists, cultural practices can have profound neurophysiological consequences. Key elements of human economic, political, and social activity … emerged precisely because humans possess relatively plastic or manipulable neural states and brain-body chemistries.”
There’s some shifting of focus here; neurohistory doesn’t necessarily have to deal with deep history (Smail includes examples of applications to more recent history), but taking neurobiology into account does set any historical study into the context of our story as a species. Although he explains in the preface his reasons for writing a book simply to propose this approach rather than trying to also sketch out what a deep history might look like, and his reasons are valid, I still wish the book had said a bit more about what might be covered in a new general history textbook that took the longer view he proposes. Maybe he’ll put that in another book. (And I do appreciate that this one was short enough to finish before I had to take it back to the library!)
A bit later in the neurohistory chapter, it says that the Neolithic revolution
“…created, in effect, a new neurophysiological ecosystem, a field of evolutionary adaptation in which the sorts of customs and habits that generate new neural configurations or alter brain-body states could evolve in unpredictable ways.”
Which is a good way of introducing the final chapter, which deals with a specific focus of neurohistory: psychotropy, or the ways humans manipulate the brain-body states of themselves and others.
Smail defines several types of psychotropy, although the definitions don’t seem to be mutually exclusive. First is teletropy, the influence of other’s moods and emotions through a variety of approaches that include things like religion or seduction. (I don’t remember that he specifically mentions art in this context, but it seems to me like another excellent example.) Teletropy can be symbiotic (both parties benefit) or exploitive, although it can be hard to draw the line, and it might be possible to describe the same behavior either way. (For example, is church-going a result of the joint interests of clergy and laity, or are the latter being exploited and duped into donating money to the former?)
In contrast to this is autotropy, the ways we have of adjusting our own mental and emotional state. These include recreational sex, reading, and gossip (taken to mean the discussion of other humans and their behavior). A subset of autotropic mechanisms that is also used sometimes in teletropy is the ingestion of substances that tweak our moods one way or another. The neurohistorical approach offers a new way to look at our relationship with these substances and practices over time, and this is the richest and juiciest part of the book, in my opinion. Toward the end of the chapter Smail suggests that:
“…it may be possible some day to argue that European societies, between the twelfth and the nineteenth centuries, witnessed a tectonic shift away from teletropic mechanisms manipulated by ruling elites toward a new order in which the teletropies of dominance were replaced by the growing range of autotropic mechanisms available on an increasingly unregulated market. (The rise of the fascist regimes of the twentieth century might well pose a challenge to the simple teleology of this model, reminding us that history is always complex and never linear.)”
I enjoy this kind of big-picture thinking, although obviously this is just the briefest of sketches to demonstrate the possible explanatory power of using a neurophysiological approach to human history. All in all, this book should provide plenty of fodder for thought and debate. Although it’s addressed to historians, I think there’s lots of material here to interest the more general reader, especially in the last two or three chapters.
Boredom and patience
I recently ran across a quote that I saved from a 2003 interview with writer Roger Angell. He was discussing baseball, which he’s covered for the New Yorker for over 40 years:
“Baseball is meant to be watched all the way through. Sure, it’s boring. There are boring innings and sometimes there turn out to be bad games, but you’re not going to have a feeling for the good games unless you’re willing to watch.
I think I wrote once that baseball in many ways is very much like reading. I said there are more bad books than bad ballgames, or maybe it was the other way around. I can’t remember. But each have formal chapters. There are wonderful beginnings that don’t stand up and boring beginnings that are great in the end. You just don’t know. They’re both, baseball and reading, for people who aren’t afraid of being bored.”
This struck me when I first read it because I sometimes feel so overwhelmed by the number of books to read and things I want to learn that I urgently want to find only the good books and not waste any time on the mediocre ones. This reminded me that you can’t always know in advance what kind of book (or baseball game, or baseball season) you’re getting into, and part of the magic of reading and watching baseball is watching things unfold and seeing how it turns out. Reading and baseball often require you to reserve judgement for awhile, and they may surprise you before it’s all over.
This quote also seems to add another dimension to the concept of boredom. Maybe the tolerance for a certain amount of boredom is one of the ingredients of patience. The world seems like a very restless place sometimes. For example, I’ve been to conferences where there’s a small steady stream of people in and out the door during each session, always searching for the absolutely best presentation in that time slot, and sometimes that seems fairly representative of life these days.
This behavior reminds me of my desire to find only the most useful and powerful books to read. OK, life is short, and sometimes it is better to cut your losses and leave, especially if you find that the content or focus isn’t at all what you thought it was going to be. Heaven knows I’m not writing in praise of bad books, or bad presentations, or sticking with something even if it’s not right for you. But surely sometimes it’s better to sit tight and see what happens next, to find out for yourself if the lackluster beginning leads to a dazzling ending, or if there are enough flashes of insight along the way that it’s worth staying the course. Maybe we’d even feel richer in time if we could afford to spend some of it on activities that are not guaranteed to be rewarding? I don’t know; I’m thinking out loud more than usual here, and I’d be glad to hear what other people think.
Living with the might-have-been
In his book Out of Control, Kevin Kelly wrote:
To evolve is to surrender choices. To become something new is to accumulate all the things you can no longer be.
(Another take on this is the advice to a first-year college student that I once heard: You can take any classes you want, but you can’t take every class you want.)
So even the luckiest lives are going to contain some paths not taken. Everyone’s life contains the ghosts of different selves that might have been developed, given another set of choices and different opportunities. Some recent research investigated the ways that people deal with their regrets, particularly in the face of a serious loss or change of course. It turns out that the people who cope the best have a higher capacity for something called complexity, the ability to see multiple facets of your own experience (e.g., the good along with the bad) and to gain meaning from even negative experiences. This capability develops over the course of a lifetime, so apparently we pick it up as we go along, if we’re lucky and/or disposed to do so.
This New York Times article describes this research in the context of a discussion on regrets. This article from Science Daily is more focused on the recent research.
And the land brought forth humans
I once heard a naturalist and nature photographer who specializes in wildlife and plants explain his interest in geology by saying, “You have to have something to put those ecosystems on!” His point was that different geological features give rise to different climates, soil conditions, and other factors that shape the living things that inhabit them, and to understand the inhabitants you have to understand the place. Two geologists at the University of Utah take this idea a bit further; they suspect that geological change played a major role in the evolution of early hominins in east Africa several million years ago.
Climate change drove our ancestors out of the trees; the forest dried up and changed to savannah, and they had to adapt to the different conditions. Some of the adaptations were probably instrumental in shaping the hominins into modern humans. But what caused the climate change?
Royhan and Nahid Gani have examined a stretch of the Wall of Africa, a chain of mountains and highlands that runs from Sudan to South Africa, and determined that the land rose by at least a kilometer (about 3,200 feet) three to six million years ago. The uplift in the area they looked at (in Ethiopia) cut the land off from much of the moisture coming from the Indian Ocean, and in doing so changed the climate and the living conditions for the primates in the area, who had to scramble to cope. Instead of living in lush jungle-like conditions, they found themselves in a much less densely vegetated and drier area. Bipedalism may be one of the most crucial adaptations to the changed landscape.
The uplift is part of the tectonic history of the region, which involves the movement of two of the plates that make up the crust of the earth. The plates are pulling apart, creating a huge rift system several thousand miles long that runs from Lebanon in the north down through the African Rift Valley and on to Mozambique. A large plume of molten rock swells toward the surface under the rift system, pushing the rocks above to either side. From such subterranean forces, much follows, including perhaps you and me.
The Ganis speculate that in addition to driving the shift to bipedalism by pushing up the Wall of Africa, the tectonic activity in the area may have driven further hominin evolution by providing varied and changeable landscapes that required ingenuity on the part of their primate inhabitants. Further research may help determine more precisely the influence that the geology of its birthplace had on humankind.
If you want a quick read that will tell you more about this work, here’s a story from Live Science. For more detail, I highly recommend this press release from the University of Utah (check out the links on the left for some nice images).
Humans, animals, and Kipling
Every day in my inbox I get a book review from the independent bookseller Powells.com. Usually they’re reviews of current books, but occasionally they’re classics, and today’s was an anonymous review of Rudyard Kipling’s Jungle Books series from the June 1898 Atlantic Monthly. It was an eye-opening read.
Written nearly 40 years after the publication of Charles Darwin’s Origin of Species, the review opens with a tribute to Kipling’s accomplishment in making the truths of Darwin’s science palpable. Kipling, in presenting the psychology of animals, has helped people “really know and feel that the larger part of our mental composition is of the same substance as that of our cousins the animals, with a certain superstructure of reasoning faculty which has enabled us to become their masters.” I haven’t read The Jungle Book, so I can’t comment on Kipling’s evocation of animal minds, but I could still appreciate this glimpse into how the relationship between humans and other animals looked at that particular point in history. And I really like the comparisons the author draws between various animal states of mind and the behavior and longings of people.
But I was fairly astonished by the first sentence of the last paragraph:
“Man, as we usually think of him, is a being of pure reason, the product and the aim of countless ages of slow and halting development.”
Leaving aside the incorrect idea of evolution as a process of development that was somehow working to produce us, I can’t imagine anyone typically thinking of humankind as beings of pure reason. Is that really how humans looked to the average Atlantic Monthly reader in 1898?
The paragraph goes on to describe the emotions, sensations, and instincts that underlie “this brilliant flower of the intellect.” The message is that we are linked by our bodily essence to the life of all the other animals, and are not really such a thing of pure reason after all, and a good message it is. But I guess I’ve been steeped long enough in the idea that the thinking part and the meat part are inextricably interdependent and linked that it seems very odd to me to think of the higher, reasoning parts of our nature lying atop and apparently in opposition to this more instinctive undergrowth that we share with the animals. We’re finding that we share more of our cognitive traits with at least some of the animals than anyone guessed (that story about macaque monkeys and arithmetic from yesterday, for example), and we’re also learning that our own reasoning is not divorced from our emotions and instincts but is bound up with them. If anything I write survives for 110 years (which is doubtful), I wonder what I’m writing today, and what assumptions I’m making, that someone from the future will find astonishing.
Human menopause unusual among primates
Some recent research indicates that chimpanzees, our closest genetic relatives, do not go through menopause as humans do. For female chimpanzees, reproductive capacity declines at the same pace as the rest of the body ages, and truly ends only with death. It’s not common for human females to have children much past the age of 40, but for chimps it happens more frequently, and there’s no prolonged period of healthy life after the reproductive system shuts down. Humans are rare or perhaps even unique in going through menopause and often having years of healthy post-reproductive life on the other side. This story from New Scientist has more information.
This ties in with a Live Science story from last year about male chimpanzees preferring older females to mate with, in contrast to human males, who tend to choose younger mates. Older female chimps are still in the running as far as having chldren, whereas female humans past a certain age are not. This is a key difference between chimp and human life patterns. (And think of how some deeply ingrained aspects of the human psyche and human culture would be different if female aging were not considered to be an anti-aphrodisiac.)
This story also brings up the perennially interesting (to 40-something females anyway) topic of life after menopause. If you’re a woman, even if you have no intention of having a child in the future, the onset of menopause can make you wonder what your role is, evolutionarily speaking. Why do human females live so long after they can no longer reproduce?
It’s hard saying for sure, but one hypothesis is that childbirth is (or used to be) dangerous enough that after a certain point it’s more genetically advantageous to stick around and raise your existing children and help raise your grandchildren than attempt to have more kids. A news story from Live Science from a few months ago talks about another possibility, perhaps working in tandem with the first. Men often choose younger women as mates, sometimes dramatically younger. When men in their 50s and 60s and 70s continue their own reproductive years by having children with a much younger woman, their children, boys and girls alike, can inherit whatever of their genetic endowment contributes to their longevity, lengthening the lifespan of the human species as a whole.
Perception of time during scary experiences
Time flies when you’re having fun, the saying goes, and it often seems that in emergency situations time slows down. However, a recent experiment indicates that people’s perception of time does not shift during a moment of danger, and that sense of everything moving in slow motion is just a trick of memory.
For the experiment, people did something called Suspended Catch Air Device diving, which involves falling backwards from a platform suspended 150 feet above a safety net. It takes only three seconds to fall, but people are moving 70 miles an hour when they hit the net. It sounds absolutely terrifying, but it’s supposedly safe, so it’s a good experience for testing whether or not time perception shifts during times of crisis.
Participants observed the falls of others and timed them, and then estimated the length of time their own fall had taken; their estimates were about a third again as long as the actual time it took to fall. However, they were wearing a gadget that flashed numbers too quickly for them to make them out, and during the fall they were not able to see the numbers any better than when they were not scared, indicating that they were not really perceiving a slowed-down world. They could see numbers flashed at a slower speed, so the problem was not with being able to read the numbers while in free fall.
What is probably happening to give people that sense of time stretching out is that the brain retains much more detailed memories of what happens in such adrenaline-charged moments. When people look back at the density of memories, it feels like the scary experience must have taken longer than it did, and in retrospect it seems like their perception of time must have expanded to allow for all that experience in such a short amount of time—but in fact it didn’t. This press release on EurekAlert has the details.
Imperfect tense
One of the things I remember hearing when I was growing up was the advice: “When a job is once begun, never leave it till it’s done. Be it great or be it small, do it well or not at all.” For some this may be an inspiration to achievement, but I found it rather daunting, and I’m afraid it left me likely to not do things at all rather than to risk doing them poorly (as people often do when they’re learning a new skill). However, I can’t blame this advice for my reaction to it, because I suspect that it’s my nature to be dissatisfied with myself anyway. I want not only to do things perfectly, but to do them perfectly the first time I try them. I know, I know, this is an unrealistic expectation. But unrealistic expectations are what perfectionism is all about.
An article on psychological studies of perfectionists discusses recent research that identifies negative thought patterns associated with depression (e.g., all-or-nothing thinking, which you’ll find listed in books on cognitive behavioral therapy as a no-no). The article also mentions a subdivision of perfectionists into three distinct types. I found this part very useful. I’m definitely the first type, hard on myself and prone to self-critical depression. I also tend to be soft-spoken and verbally gentle, even wimpy, which doesn’t match some stereotypes of the perfectionist as demanding and inflexible. However, those stereotypes may fit the second subtype, those who expect perfection in those around them. (If you are of the first type, spending time around someone of the second type can be seriously demoralizing.) Perfectionists of the third type try to measure up to a standard that they believe others expect of them.
One thing therapists try to do with perfectionists is to get them to loosen up a little bit, let some of the smaller things go, and observe that the world doesn’t stop turning as a result. Hmmm. Maybe I should try that someday. Do you think I’ll get it right the first time I try?