Before I explain the rot at the heart of this chapter (Chapter 5 of From Extraterrestrials to Animal Minds: Six Myths of Evolution, "The Myth of Animal Minds," by Simon Conway Morris), I'd like to show you my workspace as I sullenly trudge toward the end of this task.
That's my fun little Chromebook 2-in-1, and the barely-visible tartan mouse pad is from my dad. You'll see my toolkit of sticky notes and a stack of (some of) my books on consciousness and human cognition. Conway Morris' book is open to the pages (155-157, in a section called "An unbridgeable gulf?") that stopped me in my tracks.
It's one of the most famous misquoted lines in the English language, spoken by Lady Gertrude (Hamlet's mom) during the intense scene featuring a play ("The Mousetrap" aka The Murder of Gonzago) within a play, intended by Hamlet to be "the thing wherein I’ll catch the conscience of the King." The character in "The Mousetrap" has delivered some sappy lines about commitment and widowhood, designed to flush out the King and Gertrude. But you know all that. The frequently-mangled line is "The lady protests too much, methinks." It's a great line and it works out to something like "she's overdoing it" spoken by a person who is literally the subject being portrayed. When we say "the lady doth protest too much" we usually mean "they're overacting so much that now it seems even they don't believe what they're saying."
That's how Chapter 5 of From Extraterrestrials to Animal Minds: Six Myths of Evolution, "The Myth of Animal Minds," felt to me. Simon Conway Morris is hellbent on digging a conceptual moat around human cognition, desperate to isolate it from non-human cognition so that it can receive metaphysical shipments from on high. If that sounds harsh, it is—and it is exactly what the chapter is about.
Welcome to Quintessence of Dust and to the 14th Edition of the monthly Carnival of Evolution. Thanks for stopping by, and for supporting scientific carnivalia, members of a taxon that seems to be flirting with extinction.
One good reason to visit a carnival: brain stimulation. Brain Stimulant offers some thoughts and speculations on Free Will and the Brain, touching briefly on themes of selection and adaptation, and he doesn't charge as much as the clinic would.
Another good reason: you can bump into real scientists, the kind who actually work on evolution. Ryan Gregory has a day job as an expert on genome evolution, but somehow finds the time to blog at Genomicron. Recent entries there include fascinating pictures of ongoing field work. For this month's carnival, be sure to read two reviews of the ideas of Stephen Jay Gould, focusing on controversial papers by Gould published in 1980 and 1982. You may find that you have been misinformed about Gould's positions, and you'll surely learn more about evolution.
David Basanta is a biologist who runs a cool blog called Cancerevo: Evolution and cancer, which is subtitled "Studying cancer as an evolutionary disease." Check it out, and don't miss his recent piece on Stem cells and ecosystems.
Zen Faulkes is a biologist who blogs at Neurodojo. That's cool enough, but the subtitle of that blog is "Train your brain." Hey, this could be a theme for the whole carnival! He recently wrote about a walking bat in New Zealand. Bat evolution...we can't get enough of that. I've written about it myself.
Hoxful Monsters is a future host of this carnival; Nagraj recently reviewed some recent work on pattern formation in the development of spiders. Wonderful evo-devo stuff.
And that's our carnival. Thanks for reading, and on the way out I hope you'll look at my nearly-complete series on Notch and deep homology.
Next month's edition will appear at Southern Fried Science. To submit posts, use the submission form found at the Carnival of Evolution site. And if you like the carnival, help us promote it with a link, and/or consider hosting. More info at the carnival site.
Well, it's the first sampler since June, but I won't try to make up for lost time.
1. Todd Wood has started a blog, and it's excellent. His slant is unique -- he's a young-earth creationist -- but his writing is superb and his expertise in genetics and genomics is world-class. My favorite entry so far: a commentary on a recent report describing genetic variation among humans. The most recent post deals with the principle of accommodation and one of its Enlightenment defenders, one John Wilkins. Todd hasn't activated comments, so expect a journal and not a conversation. But have a look, and consider the gigantic difference between Todd's work and Mike Behe's. There's just no comparison, and Todd is an example of why one should not grant respect based solely on someone's willingness to accept an ancient universe or universal common descent.
2. Okay, best segue ever. Speaking of John Wilkins, Evolving Thoughts (a blog at ScienceBlogs run by a philosopher of biology) has some very interesting recent posts defending "theistic evolutionists" like me. Back in September, he discussed "Darwin, God and chance" and concluded:
Why does this matter beyond a bit of mental gymnastics, especially since I am not a theist? Well it has one rather significant implication: it means that those who criticise theistic evolutionists (like Asa Gray) for being inconsistent or incoherent are wrong: it is entirely possible to hold that God is not interventionist, and yet hold that God desired the outcomes, or some outcomes, of the world as created. In simpler terms, there's nothing formally wrong with believing the two following things: 1, that God made the world according to a design or desired goal or set of goals; and 2, that everything that occurs, occurs according to the laws of nature (secondary causes). In other words, it suggests that natural selection is quite consistent with theism, solving a problem I discussed earlier.
Read the whole post to see how he arrived at this conclusion, and don't miss the work of his collaborator, one Phil Dowe. More recently, Wilkins has summarized the "theistic evolution" position as he sees it, and reiterated his contention that the position is not incoherent. (Well, duh, but there are plenty of axe-grinding nitwits who assert just that.) I'll discuss these ideas in a separate post soon; in the meantime, pay Wilkins a visit.
3. Steve Martin's blog An Evangelical Dialogue on Evolution has become the blogospheric world headquarters for multilateral discussion of evangelical approaches to the theological understanding of evolution. The most recent series tackled questions of evolution and original sin, centered on an article by George Murphy and featuring responses by Terry Gray, Denis Lamoureux and David Congdon. Congdon's blog, The Fire and the Rose, is one of my favorites.
Left, the human eye as sketched by Descartes. Right, the eye of a fruit fly as revealed by scanning electron microscopy. Courtesy of Wellcome Images, Creative Commons license.
4. The most recent issue of Evolution: Education and Outreach is devoted to the evolution of eyes. And it's all free. Includes an introduction by Ryan Gregory, who also points us to an issue of The Lancet that focuses on evolution. Sheesh, is there some kind of anniversary coming up? :-)
5. Illusions of various kinds are something of a hobby of mine. Hence my interest in an online collection of kinetic optical illusions at Scientific American (meaning that the images produce an illusion of movement). Something else that's cool about the collection: some of the illusions were created (or discovered) by Donald MacKay, a Christian neuroscientist who has influenced me and many of my colleagues through his vigorous and uncompromising approach to the relationship between science and Christian faith. (We read part of his Science, Chance and Providence in our randomness reading group.) Make sure you look at the third image -- it's the infamous Enigma illusion.
6. Here's another kind of illusion that is interesting and informative: synesthesia, in which a perception (such as smell or color) becomes associated with a seemingly unrelated experience (a number or a different sensation). V.S. Ramachandran devoted one of his Reith Lectures to this phenomenon, which he described as "mingling of the senses." A new report describes a new version: touch-emotion synesthesia, in which certain textures evoke particular emotions. The proposed explanation for how these peculiarities is worth a look, too.
7. Using bumps in the road to make music. It'll be a clue in National Treasure 3, you just wait. Note that this link comes courtesy of Very Short List, which is a delight.
8. Deb and Loran Haarsma's excellent book Origins got a nice review at the Reports of the NCSE. I'll write one of my own sometime this spring. When the next issue of RNCSE goes online, I hope it will include my review of Gordon Glover's Beyond the Firmament.
It's snowing again. Cycling seems like a childhood memory. You'd think this would give me more opportunities to work on blog posts. Gah.
1. My friends and colleagues, Debbie and Loren Haarsma, were the subject of a nice local news story, focusing on their work as scientists and Christians. They have a superb new book out, which I've promised to review here sometime soon.
2. Is evolution too difficult or complicated for secondary students to grasp? This is a question that was discussed in the blogosphere recently, and even when religious/cultural debris is cleared away, I think the question is still a good one. (Add the religious/cultural influences back in, and you realize that teaching evolution at any level entails both the careful explication of the relevant principles and the careful dismantling of deliberately-introduced misinformation.) Some of the key concepts in evolutionary theory are decidedly non-intuitive. For example, I have the impression that it's just plain hard for people to get their heads around the notion of different species (let alone different families, orders, etc.) springing from a common ancestor. Maybe it's the ongoing influence of old errors (in this case, I think, orthogenesis), but I do wonder if common descent is one of those ideas that our kludgy brains just don't get straight off.
But of course that doesn't mean evolution can't be effectively taught to high schoolers. Algebra, after all, doesn't come naturally to most people, but I haven't seen anyone seriously propose that it be removed from high school curricula.
In fact, I think evolution is a lot like algebra. It takes time to teach right. It's a demanding subject, but it's within the capacity of high schoolers to understand. Levels of mastery and comprehension will vary significantly. Teachers who are poorly-trained and/or unprepared may do more harm than good. The main difference between evolution and algebra is this: there are no ministries or institutes devoted to hindering the work of algebra teachers. (Well, okay, there's MTV, but you get my point.)
3. And on that subject, PBS (WGBH Boston) has collaborated on the development of some resources for instructor professional development, with the aim of providing "the background and skills they need to counter pressures to present or address religiously based alternatives to the theory of evolution." The tools draw on materials from NOVA's "Judgment Day" episode on ID and Dover. I've only browsed, but there looks to be some very good stuff on the site. Maybe I'll comment further sometime.
4. Until this week, I was unaware of the ministry of Timothy Keller and Redeemer Presbyterian Church in New York City. Redeemer alone is an interesting and encouraging story, but now Keller has published a book in which he discusses (among other things) evolution. He was recently interviewed by First Things, and his comments were discussed extensively on the ASA listserv, where some errors (or simplifications) were dissected. It would be interesting to compare his thoughts with those of Tony Campolo: both accept evolutionary science, but "timidly" as one ASA commenter put it.
5. Oliver Sacks is now blogging (occasionally) at the New York Times, in a blog devoted to migraines. (Subtitled "Perspectives on a Headache." Ouch.) I'm not terribly interested in migraines, but if Oliver Sacks wrote an essay about sawdust, I'd read it with rabid anticipation. A recent piece on patterned visual sensations accompanying migraine auras begins with Sacks' description of his own experiences, and ends with musings on the potential universality of "self-organization," with the typical breathtaking Sacks prose beating the path. (Via Neurophilosophy.)
We interrupt this series on "junk DNA" and rampant folk science to bring you a months-overdue Journal Club.
I wonder how many of my readers remember this little tidbit of American genius:
I remember some very funny spoofs, mostly on T-shirts. (Back then, I think the Internet was still a toy for geeks at the NCSA.) "This is your brain. This is your brain on drugs. This is your brain on drugs with a side of bacon. Any questions?"
Marijuana, as I recall, was typically included as one of the frying pans that could turn your central nervous system into a not-very-heart-healthy staple at Denny's. It was – and probably still is – easy to get the impression that smoking pot would hollow out your skull and make you into the inspiration for a character played by Keanu Reeves.
But that's baloney. Long-term marijuana use is certainly not without effects on the brain (duh), but its most abundantly-documented pathological outcome is, well, stupidity. (Mild stupidity. How such an effect is detected in an American population is not so clear to me.) And gosh, if we intend to stamp out stupidity-enhancing behavior through legal action, we'd better send the Marines to Hollywood right now. Seriously, there are few well-established long-term negative effects of using cannabis, and most of those are associated with smoking marijuana and not with the neurological impact of cannabis itself. (Full disclosure: I have never had a joint to my lips, and the closest I've come to inhaling is second-hand at the occasional concert. It would seem that my stupidity has a different cause.)
The rules are different, though, when developing brains are the subject, and it doesn't matter whether the neuroactive substance is legal or not. Maybe pot doesn't mess up a young adult's brain, but that doesn't mean it won't affect a fetal brain. And in fact, some recent studies indicate that we should pay close attention to the possibility that fetal brain development is affected by cannabis. One of those studies, "Hardwiring the Brain: Endocannabinoids Shape Neuronal Connectivity" by Paul Berghuis and colleagues, published in Science last May, suggests that mammalian prenatal brain development is likely to be significantly impacted by cannabis. It's an interesting paper for that reason, and because it deals with two of the subjects of my own research: neuronal growth cones and Rho GTPase signaling. I'll briefly explain those terms later.
The active ingredient in pot is a chemical called Delta(9)-tetrahydrocannabinol, or THC. THC affects the brain by activating receptors on particular types of neurons in the brain, causing these neurons to release less of their neurotransmitters (the normal chemical signals used for communication among neurons). While a serious intelligent design proponent might need to claim that the "purpose" of these receptors is to help people respond to pot (to suppress nausea while on chemotherapy, for example), scientists instead sought and found the chemicals within the brain that normally act on these receptors. These chemicals are called endocannabinoids, signifying that they are cannabis-like but originate from within. (After biologists discovered the endocannabinoids, they subsequently discovered the receptors, but that's not an issue here.)
This means that a first step toward discovering the potential roles of endocannabinoids in brain development is the identification of the parts of the developing brain that display the receptors. If you know where the receptors are, then you know where the chemicals are likely to act. And those are the areas that are likely to be affected by cannabinoids like THC, that come from outside.
Neurons are the brain cells that send and receive electrical signals. A typical neuron has many (perhaps thousands) of dendrites, which receive signals from other neurons, and one axon, which transmits signals to other cells, often a great distance away.
During brain development, neurons have to develop their magnificent and specific architectures. Beginning as a boring little round ball, a neuron has to sprout and extend dendrites and (typically) a single axon. The axon must somehow migrate to its final position, which may be in a completely different part of the body or right next door.
When Berghuis et al. looked for endocannabinoid receptors in the developing brain, they found them in the cerebral cortex, and specifically they found them in the growing axons of the cerebral cortex. In case you haven't been introduced to the cerebral cortex, it is thought to be responsible for "all forms of conscious experience."
Layers of the developing cerebral cortex of a mouse. The red streaks are developing axons that are displaying endocannabinoid receptors. From Berghuis et al., Figure 1D.
They found the receptors in other developing brain regions, too, and they showed that the endocannabinoids are likely to be produced in those regions at those times. The somewhat surprising result raises the possibility that cannabinoids affect how the brain develops, by affecting how the axons develop.
What might these effects be? The authors found that the receptors were clustered right at the growing tips of these developing axons. This region is called the growth cone, and it's one focus of my own research, because it's obviously the place where the axon is continuously elongating, and it's a place where the skeleton of the cell must be always remodeling.
The growth cone of a mouse neuron. The red indicates structural elements of the growth cone; the green blobs are endocannabinoid receptors, and the yellow smudges indicate where the red and green overlap. From Berghuis et al., Figure 2C.
If endocannabinoid receptors are located right on the growth cone, then they are positioned to influence speed and direction of axon outgrowth. Yikes!
Okay, so endocannabinoids (and, of course, THC from pot smoke) are uniquely positioned to affect growing axons in the brain. But what's the effect? The authors show that one effect is the inhibition of steering mechanisms in the growth cone. In my favorite experiment, they put neurons into an electric field, where the growth cones tend to steer toward the negative pole. When the neurons were treated with an endocannabinoid, they failed to show this preference.
Axon growth in an electric field. Each black tracing represents the behavior of one axon. On the left, notice that untreated axons tend to grow toward the negative pole (left side), and many of those that are growing toward the positive pole are turning away from it. On the far right, notice that axons treated with the endocannabinoid grow in every direction and don't care about the electric field; the center shows how they grow when there's no electric field at all. From Berghuis et al., Figure 3D .
The authors went on to show that this effect seems to result from the activation of a well-known signaling system inside cells, mediated by a protein called RhoA. RhoA is a Rho GTPase, and I'll spare you the details since you've probably read all my papers already. :-) What matters is this: Rho signaling is known to be involved in axon growth, and is generally a negative influence on axon growth. In fact, some attempts to stimulate axon growth in the spinal cord after injury (and paralysis) are focused on the inactivation of RhoA and its partners. So this connection between endocannabinoids and Rho GTPases is further evidence of a specific – and likely negative – influence of cannabinoids on axon outgrowth in the developing brain.
But is there any evidence of a specific effect on brain development, in an animal? The final experiment presented in the paper is a genetic experiment, in which the authors examined the brains of mice in which the endocannabinoid receptor (one in particular) was genetically deleted in certain parts of the brain. And they found that certain neurons in the cerebral cortex of these mutant mice had lost almost half of their inputs, presumably due to the inability of the incoming axons to find their way to the recipient neurons. In other words, when the receptors were deleted from a subpopulation of neurons, those neurons evidently had trouble making their normal connections.
What this means is that to whatever extent the human brain resembles the mouse brain with regard to expression of cannabinoid receptors and their function in growth cones, the developing human brain is potentially vulnerable to damage, or at least alteration, by exposure to THC. And as the authors note, this may partly explain recent findings (in rats) that point to permanent alterations in brain function in pot users – alterations that may predispose these people to much more serious addictions.
I've long been inclined to skepticism regarding anti-pot hysteria, and I strongly support efforts to legalize and legitimize medical use of cannabis. But these data should make us look hard at the potential implications of cannabis exposure during human development.
Article(s) discussed in this post:
Berghuis, P., et al. (2007) Hardwiring the Brain: Endocannabinoids Shape Neuronal Connectivity. Science 316:1212-1216.
Lady Macbeth [to Macbeth]: Great Glamis! worthy Cawdor!
Greater than both, by the all-hail hereafter!
Thy letters have transported me beyond
This ignorant present, and I feel now
The future in the instant.
Obsessions with self-preservation
Faded when I threw my fear away
It's not a thing you can imagine
You either lose your fear
Or spend your life with one foot in the grave
Is God the last romantic?
Optimism or delusions of grandeur? Bullish or blinkered? Looking on the bright side, or gazing through rose-colored glasses? Am I a romantic, or am I just in denial?
I do consider myself a romantic, and this blog is a testament to a particular form of optimism that I just can't shake off: I'm ever hopeful that people (like me) can learn new things and change their minds. But sometimes I worry: is my optimism (on this subject, and hundreds of others) unreasonable? Or worse...is my optimism unreasonable but also adaptive, a pitiful delusion without which I can't otherwise get by?
[Waits for jeers of skeptics to die down] Actually, being (overly) optimistic is apparently a universally human trait. I may be a romantic, but...I'm not the only one. (Imagine!)
Consider these opening sentences in a research article ("Neural mechanisms mediating optimism bias," Sharot et al., Nature 450:102-105) published in Nature this week:
Humans expect positive events in the future even when there is no evidence to support such expectations. For example, people expect to live longer and be healthier than average, they underestimate their likelihood of getting a divorce, and overestimate their prospects for success on the job market.
Lord, what fools these mortals be! Yes indeed; but how does this happen? The study by Sharot et al. set out to identify mechanisms in the brain that might account for what they call "pervasive optimism bias." First the authors note that this "optimism bias" is considered to be a mark of good mental health, and exhibits apparent adaptive value; excessive pessimism correlates with symptoms of depression, and of course excessive optimism can lead to recklessness. A "normal" dose of optimism, they note, "can motivate adaptive behaviour in the present towards a future goal." Nevertheless, the authors describe this normal (wild-type?) human stance as "a moderate optimistic illusion." Yikes! We're all deluded.
Okay, so how does this work? Previous work has shown that, when imagining the future, people use the same brain systems that they employ when recalling the past, suggesting that the construction of an imagined future involves the rearrangement of pictures and stories from the remembered past. So we might expect to see these systems somehow involved in the expression of optimism.
The authors used functional MRI (fMRI) to look at brain activity while subjects were thinking about events in their lives that centered on a "life episode" like "winning an award" or "the end of a romantic relationship." They correlated the brain imaging with the participants' ratings of their experience of these episodes, which were either past or future events (i.e., recollections or imagined scenarios). And they used a psychological test (the Life Orientation Test-Revised, or LOT-R) to measure "trait optimism" and thereby estimate the relative optimism or pessimism of individual experimental subjects.
The behavioral data alone reveal some interesting things about people and their optimism. Amazingly, future positive episodes were judged to be more positive than past positive events, and were felt to be closer in time than any other experience, past or future. And there's more:
Negative future events were experienced with a weaker subjective sense of pre-experiencing, and were more likely to be imagined from an outsider viewing in, than positive future events and all past events (Fig. 1b). The more optimistic participants were, as indicated by the LOT-R scores, the more likely they were to expect positive events to happen closer in the future than negative events, and to experience them with a greater sense of pre-experiencing (Fig. 1c, d).
So, humans in general seem to think (or feel) that the future looks better than the past, and optimistic people seem to be able to better connect with the positive illusion of the future that they create.
Combining the various techniques enabled the authors to identify some brain regions of interest (ROIs) with regard to optimism. Some of these areas are The Usual Suspects: the rostral anterior cingulate cortex (rACC), the posterior cingulate cortex, and the dorsal medial prefrontal cortex, all areas that were previously implicated in autobiographical memory recall and in the construction of imagined future scenarios. Activation of these regions accompanies optimism, presumably because optimism requires a vision of the future. That's all interesting and informative, but it's not what makes this paper so intriguing. I think the paper's real impact arises from the fact that the imaging analysis implicated a fourth brain area in optimism bias: the amygdala. This region of the limbic system is famously involved in emotional processing, and the authors suggest that the amygdala's role in optimism is to add emotional impact to the imagined future events. They demonstrate "strong functional connectivity" between the amygdala and the rACC during the process of imagining future positive events, and not while imagining negative scenarios. And, importantly, they document a correlation between the strength of activation of the rACC and the overall optimism of the person, as measured by the LOT-R. I find this graph compelling: Two aspects of their discussion are worth noting. First, not surprisingly, the authors highlight the relevance of their findings to the understanding of depression. Perhaps depression causes -- or arises from -- malfunctioning of the systems that Sharot et al. have implicated in optimism. Second, the authors make an important distinction between remembering and imagining in the interpretation of their results. Namely, there are two potentially relevant differences between remembering and imagining: the temporal difference (past versus future) and the reality difference (real versus imaginary). The authors speculate that the optimism bias functions when constructing imaginary scenarios, and that the past versus future distinction is only relevant because the past is real and the future is imaginary.
In any case, the article provides another glimpse into the workings of the hunk of meat in our skulls, a messy wet organ that somehow creates memories and imagination, and in the process conjures various carrots, hanging out there in front of us, urging us to ignore our (reasonable) fears and plunge into an unknown future, eyes on an illusion concocted by...functional crosstalk between the amygdala and the rostral anterior cingulate cortex.
That last part didn't sound quite right. But I think that's the way it is. And I think Christians should get used to learning how various aspects of humanness are explainable on the basis of the workings of the brain.
Now I'll imagine a future where my blog article, on the brain systems that fill us with optimism, is being read by scores of people, all picturing their own private versions of the grail beacon.
Souls will come up regularly in this blog, for lots of reasons. For one, disembodied spirits (wandering souls, I presume) are everywhere in Shakespeare, and his very conception of death seems to be the separation of the soul from the body. I can't very well bring up Shakespeare without conjuring ghosts or visions thereof. Such visions are utterly commonplace in Western literature and thought, and Shakespeare certainly didn't cook them up (I recall spirits fluttering out of dead warriors in the Iliad, and that little piece of work was conceived just a few millenia before the Bard). The picture of someone "giving up the ghost" (hilariously pictured in "Who Framed Roger Rabbit?", if you remember that little gem) obviously inspires Romeo:
Now, Tybalt, take the villain back again That late thou gav’st me; for Mercutio’s soul Is but a little way above our heads, Staying for thine to keep him company: Either thou, or I, or both, must go with him.
--Romeo and Juliet, Act III, Scene I (The Oxford Shakespeare)
We need souls in our poetry, even when our poetry has no soul. Hamlet without souls? No such thing.
And of course, we need souls in Christianity. We're essentially dualists, meaning that we believe in everlasting souls encamped (or entrapped) in mortal bodies. Right?
But whether or not you're an agnostic on immaterial souls, you should find the notion of "embodied emotion" interesting, because:
It's cool science, and of course you love cool science;
You're a human, and humans, it seems to me, are dualistically inclined;
Souls are linked to various cognitive phenomena, including emotion;
You're reading a blog called Quintessence of Dust, for heaven's sake.
The 18 May 2007 issue of Science features a "Behavioral Science" theme, and includes a brief review of some new applications of theories of embodied cognition to the study of human emotion. The author, Paula M. Niedenthal, contrasts such theories with traditional models of human cognition built around the image of brains (and minds) as computers, and identifies the following assertion as distinctive of theories of embodied cognition:
...that high-level cognitive processes (such as thought and language) use partial reactivations of states in sensory, motor, and affective systems to do their jobs. Put another way, the grounding for knowledge -- what it refers to -- is the original neural state that occurred when the information was initially acquired. If this is true, then using knowledge is a lot like reliving past experience in at least some (and sometimes all) of its sensory, motor, and affective modalities.
The idea, then, is that when you think, you are in some ways reenacting the scenario or the information itself. You are thinking with your whole body, not just with the meat-based computational soul-center in your skull. (As cool as that thing is.) If you are, like I am, a fan of Antonio Damasio and his ideas, then you're already familiar with this type of thinking and theorizing, and with the connection he makes between emotion and consciousness.
So...body is connected with emotion, emotion with cognition...doesn't this mean, then, that your body -- muscles, bones, tendons, mundane animal machinery -- can influence, even control, your cognition? Hello, Professor Descartes? If you just smile, can that make you happy?
Well, consider some of the wild stuff in this article. In one experiment, subjects were registering their perception of a projected image by moving a lever. When they saw the image, they were to quickly move the lever. The participants surely thought the experiment was measuring their reaction time, and they were partially correct. But they probably couldn't have discerned the variable of interest: whether the lever was pulled, toward the body, or pushed away. In the experiment, images were flashed, some that would be emotionally positive, some negative. Subjects who were pushing the lever away responded more quickly to negative images, and vice versa.
Maybe I'm the only one, but that kind of thing really messes with my dualistic impulses. (And I'm not a body-soul dualist.) But there's more. The author describes some of her group's work, in which activity in 4 facial muscles was recorded while subjects were judging the emotional content of certain words. Here's her synopsis of the results:
...individuals embodied the relevant, discrete emotion as indicated by their facial expressions...in the very brief time it took participants to decide that a "slug" was related to an emotion (less than 3 seconds), they expressed disgust on their faces.
The author also describes the elegant control experiment: the subjects looked at the words in print and determined whether they were written in all caps. No such embodiment was detected in the facial muscle recordings.
You might think, "gee, it must take a lot of time to do all that embodying work when making decisions." You'd be right: the author describes experiments that show timing costs associated with switching systems (or modalities):
They are slower to verify that a "bomb" can be "loud" when they have just confirmed that a "lemon" can be "tart" than compared to when, for example, they have just confirmed that "leaves" can be "rustling."
And you might wonder whether we could alter your emotional state by forcing you to embody a particular state. Suppose we force you to smile; will this make you happier? Call me silly, but my initial response to this hypothesis is to scoff. But wait: inspired scientists are testing hypotheses very much like this one.
In the last experiment described by Prof. Niedenthal, each subject was asked to determine whether a sentence described something pleasant or unpleasant, while holding a pen in his or her mouth. Huh? Have a look at Figure 1 (you don't need a subscription to Science): holding a pen with the lips precludes smiling, and even seems to embody the opposite; holding a pen with the teeth forces the lips into a smile. I suppose you know what's coming:
Reading times for understanding sentences describing pleasant events were faster when participants were smiling...sentences that described unpleasant events were understood faster when participants were prevented from smiling.
"Smile and laughter comes thereafter." Pretty corny stuff; it can still make me faintly nauseous (another embodied emotion, clearly). But maybe it's true. And if the eyes are the windows of the soul, what does that make the jaw muscles?
