Building on previous brain imaging research that revealed cultural influences play a role in neural activation during perception, Arthur Aron, Ph.D., Professor of Psychology at Stony Brook University, and colleagues, completed a study that suggests individuals who are highly sensitive have cognitive responses that appear to not be influenced by culture at all.
Reported in advance online in Social Cognitive and Affective Neuroscience, and scheduled for print in the June issue, the study could serve as a foundation for the direction of study in the emerging field of cultural neuroscience.
“Our data suggest that some categories of individuals, based on their natural traits, are less influenced by their cultural context than others,” says Dr. Aron.
He adds that the study is the first to analyze how a basic temperament/personality trait, called sensory processing sensitivity (SPS), interacts with culture and neural responses.SPS is characterized by sensitivity to both internal and external stimuli, including social and emotional cues. Scientists estimate that something like high sensitivity is found in approximately 20 percent of more than 100 species, from fruit flies and fish to canines and primates and has evolved as a particular survival strategy that differs from the majority.
The standard measure in humans is the Highly Sensitive Person (HSP) Scale, previously developed by Dr. Aron and his wife, Dr. Elaine Aron. An example of one item on the HSP scale is “do you seem to be aware of subtleties in your environment.”
Dr. Aron says those who score high on the scale report being easily overwhelmed when too much is happening, startle easily, are conscientious, enjoy the arts more, and have a lower pain threshold. They are more emotionally reactive and more affected by the environment compared to those who score low on the scale.
The researchers measured SPS in 10 East Asian individuals temporarily in the U.S. and and 10 Americans of Western-European ancestry. In a previous study, these same 20 individuals had undergone brain functional magnetic resonance imaging (fMRI) while performing a cognitive task of comparing the length of lines inside boxes.
The participants’ responses to the task tested their perception of the independence versus interdependence of objects as the fMRI measured the neural basis of their responses.The major finding of that study was that the frontal-parietal brain region (see Figure in original news release) known to be engaged during attention-demanding tasks was more activated for East Asians when making judgments ignoring context, not their specialty, but was more activated for Americans when making judgments when they had to take context into account, not their specialty. This discovery, says Dr. Aron, illustrated that each group engaged this attention system more strongly during a task more difficult for them because it is not generally supported by their cultural context. That is, even when doing a simple, abstract cognitive task, culture influences perception.In the SPS study, Dr. Aron and colleagues took the brain activations in these two groups from the previous study and considered them in light of the SPS scores of the same individuals. They found SPS as a trait yielded a very clear pattern of results:
“The influence of culture on effortful perception was especially strong for those who scored low on the scale measuring sensitivity, but for those who scored high on the measure (highly sensitive individuals), there was no cultural difference at all,” says Dr. Aron.
Regarding the fMRI, Dr Aron adds: “Culture did not influence the degree of activation of highly sensitive individuals’ brains when doing the two kinds of perceptual tasks used in the previous study. "Also, how much they identified with their culture had no effect.
"It was as if, for them, culture was not an influence on their perception.”
Dr. Aron emphasized that the new research suggests that characteristics possessed by high SPS individuals, such as being emotionally reactive or conscientious, actually flow out of or are side effects of the overriding feature of processing information more thoroughly than low SPS individuals.While the results showed a clear, statistically significant connection between SPS, cognitive processing, and culturally-based thinking, Dr. Aron indicates that the small numbers of participants does not rule out the possibility that these results could be sample specific, so conclusions must be taken as preliminary and only as suggestive.
Replications of the study and larger sample sizes, he adds, would help to further the research.
Co-authors of the study titled, “Temperament trait of sensory processing sensitivity moderates cultural differences in neural response,” include: Sarah Ketay, Ph.D., Mount Sinai School of Medicine; Trey Heddan, Ph.D., Massachusetts Institute of Technology (MIT); Elaine N. Aron, Ph.D., Stony Brook University; Hazel Rose Markus, Ph.D., Stanford University, and John D.E. Gabrieli, MIT.
Depression has long been associated with vision - and to colour perception in particular - and the link between them is evident in everyday language. Depression is, of course, often referred to as "feeling blue", and those who suffer from it are sometimes told to "lighten up". The link can be found in art, too - Picasso's so-called "Blue Period", for example, which was brought on by the suicide of his close friend Carlos Casagemas, is characterised by a series of striking paintings in shades of cold blue, which express the deep melancholy he felt at the time.
Although the association between depression and colour is largely metaphorical, there is actually some evidence that they are closely linked. The most recent comes from a new study by German researchers published in the journal Biological Psychiatry. The study shows that depressed people have reduced sensitivity to contrast, and therefore that they may perceive the world differently from others. It also suggests that depression can be diagnosed by objective measurements of electrical activity in the eye.
Earlier work has already shown that there is a physiological link between depression and vision. It has long been known, for example, that reserpine, a drug which is prescribed for psychosis and hypertension and which induces depression in humans, causes excessive sensitivity to light in various animals. Other studies have shown that patients with major depressive disorder (MDD) may also be supersensitive to light and that this can be reversed by anti-depressants; that depression causes changes in the electrical activity of the brain in response to visual stimuli; and that this change in activity can be altered by antidepressants.
Last year, neuropsychiatrist Ludger Tebartz van Elst of the University of Freiburg and his colleagues reported that patients with MDD exhibited a reduced sensitivity to contrast, while a team of researchers from Yale showed that visual motion perception is enhanced in depression. But these experiments could not establish whether the observed changes were due to alterations in the retina or the various parts of the brain through which visual information travels and is processed. And because they were based on the conscious experiences of the participants, the reported effects could have been modulated by attentional or other mechanisms.
For their latest study, van Elst's group sought to confirm their previous findings using objective methods, and to determine if any observed changes in the contrast sensitivity of depressed patients are due to changes in the eye or brain. They recruited 40 patients diagnosed with MDD and 40 matched, healthy controls. They presented the participants with visual stimuli consisting of black and white checkerboard patterns, and used pattern electroretinography (PERG) to measure the response to the patterns. The PERG is evoked by viewing patterned stimuli and, in this case, its size is indicative of contrast gain. It is recorded at the cornea, and is thought to represent the activity of the retinal ganglion cells, which are involved in the early processing of visual information and whose axons form the optic nerve that carries the information into the brain.
Specifically, the researchers looked for differences between the two groups of participants in activity reflecting contrast gain, the process by which cells in the retina adapt to variance in the light intensity of the visual scene so that the amount of information extracted from it can be maximized. They found a significant difference in the contrast gain-related activity between the depressed patients and controls. The participants diagnosed with depression displayed a marked reduction in contrast gain when compared with the controls. The reduction was observed in both medicated and unmedicated patients. Those taking medication for their depression, however, had slightly lower depressivity scores and correspondingly better contrast gain than unmedicated patients.
Furthermore, the reduction in contrast gain was strongly correlated with the severity of depression - the more severe the depression, the greater was the observed reduction in contrast gain. No difference was observed between patients with recurrent depression and those experiencing their first episode of the condition, or between depressed patients taking selective serotonin uptake inhibitors such as fluoxetine (Prozac) and those taking tricyclic antidepressants such as imipramine. The intensity of the treatment, or dose being taken, did not affect the reduction in contrast gain observed in the depressed patients. Finally, the researchers could predict, with an accuracy of greater than 90%, which of the participants had been diagnosed with depression on the basis of their electroretinographic recordings.
This is a pilot study whose results need to be replicated. Nevertheless, it shows that processing of visual information related to contrast is altered in the retinae of depressed patients. A likely consequence of this is a reduced ability to perceive contrast - depressed people may indeed experience the world as being less colourful. The study further suggests that PERG could be useful in diagnosing and objectively measuring depression. It's still unclear, however, whether reduced contrast processing is a specific marker of depression. The same effect could possibly occur in patients with other neuropsychiatric conditions such as schizophrenia, and this is could be investigated in future work.
Bubl, E., et al. (2010). Seeing Gray When Feeling Blue? Depression Can Be Measured in the Eye of the Diseased. Biol. Psychiatry 68: 205-208. DOI: 10.1016/j.biopsych.2010.02.009.
This review by Dan Lloyd, Professor of philosophy at Trinity College, Connecticut on two new books on the embodied mind appeared in the American Scientist.
SUPERSIZING THE MIND: Embodiment, Action, and Cognitive Extension. Andy Clark. xxx + 286 pp. Oxford University Press, 2008.
OUT OF OUR HEADS: Why You Are Not Your Brain, and Other Lessons from the Biology of Consciousness. Alva Noë. xvi + 214 pp. Hill and Wang, 2009.
Sum res cogitans. “I am thinking substance.” With these words, written in about 1640, René Descartes simultaneously created the modern mind and gave it a huge philosophical headache. Cartesian dualism opened an abyss between mind and matter, which was good news for mechanistic physics. But “thinking substance” was thereby expelled from nature, and psychology has labored ever since to bring the mind back into the scientific fold—an effort that has culminated with the rise of cognitive neuroscience. A modern-day Descartes would perhaps say, “I am synaptic substance,” or, to be more accurate, “I am the information transmitted across neural networks.” Sum cerebrum.
Swapping brain for mind bridges the metaphysical gulf, but lesser dualisms still haunt cognitive science. The popular thought experiment of a “brain in a vat” captures the intuition that cognition and consciousness depend exclusively on the machinery between our ears. In the standard vat tale, one is asked to imagine that one’s brain has been removed from one’s body and placed in a vat of nutrient fluids, and that all of its normal neural inputs and outputs are being simulated by a supercomputer. The brain has no way of knowing whether it is in a skull or in a vat. Can we be sure that this is not our current situation? How do we know that anything beyond our brains is real rather than virtual? The moral of the thought experiment seems to be that the neural representations of body and world are only indirectly related to real external things. Is this state of affairs an anachronistic “Cartesian materialism,” with a neural computer on one side, and the body and world on the other?
A contemporary movement in cognitive science looks beyond this lingering dualism, promoting “extended cognition” and “embodiment” as crucial components of the science of mind. Andy Clark, author of Supersizing the Mind, and Alva Noë, author of Out of Our Heads, are preeminent expositors of extended and embodied cognition, and their two books represent the state of the movement, complete with its internal tensions.
Clark critiques what he calls the “brainbound” model, which depicts the mind “as essentially inner and, in our case, always and everywhere neurally realized.” He puts forth a contrasting model, which he refers to as EXTENDED, “according to which thinking and cognizing may (at times) depend directly and noninstrumentally upon the ongoing work of the body and/or the extraorganismic environment.” He further characterizes this model as follows:
According to EXTENDED, the actual local operations that realize certain forms of human cognizing include inextricable tangles of feedback, feed-forward, and feed-around loops: loops that promiscuously criss-cross the boundaries of brain, body, and world. The local mechanisms of mind, if this is correct, are not all in the head. Cognition leaks out into body and world.
The first section of Supersizing the Mind surveys work in which considerations of embodiment and extended informational resources have transformed theories of perception, cognition and motor control. Consider the problem of walking—easy for us, but a challenge for robots, especially if their walking is highly engineered via exact mechanical control of every joint, precalculated in a central controller. Such highly motorized and micromanaged movement is inefficient both physically and computationally. Biological walking, in contrast, exploits the “passive dynamics” of the material body. We ride on springy, free-swinging limbs. Once set in motion, animal bodies like ours saunter on their way with minimal shoving and shaping from the brain.
Our bodies lighten the load for our brains in many other ways as well. Expressive gestures, including words, Clark observes, are not merely communicative output but may also “function as part of the actual process of thinking.” Gestural information can interact with language. As we talk (to others and to ourselves), we also listen, using our bodies and words as reminders and abbreviations. Outsourcing is truly powerful, however, when we exploit the myriad cognitive scaffolds of the world around us, particularly the world of artifacts. In general, when information is available in the environment, we will use it instead of framing a “brainbound” thought. For example, to play the video game Tetris, one must anticipate whether moving shapes will fit together. To test for a match, one can manipulate the shapes mentally or try out the rotations on screen. Skilled players use on-screen manipulation rather than tax their minds.
The picture of mind that emerges in Clark’s treatment, although not “brainbound,” remains neurocentric. He portrays the brain as a lazy genius at the center of a loose confederacy of tricks and tweaks. Some of the outsourcing involves symbol manipulation and some involves shortcuts that eliminate the need for language (or other symbols) altogether. Clark’s vision loosens up cognitive science itself: Good old-fashioned computational models still have a place, albeit a diminished one. We need to be alert to every kind of computation (including dynamical systems of distributed representations) and, more important, to the diversity of vehicles for computation, many of which are outside the head.
One consequence of the extended approach is a “hypothesis of cognitive impartiality”:
Our problem-solving performances take shape according to some cost function or functions that, in the typical course of events, accord no special status or privilege to specific types of operation (motoric, perceptual, introspective) or modes of encoding (in the head or in the world).
Cognition doesn’t care how or where it occurs! Extended theorizing in the spirit of this hypothesis could reshape cognitive science, embedding embodied human life in an ecology of useful and symbolic objects, a flow in which neural activity is one eddy among many.
Extended cognition entails a supersized mind, and much of the second part of Clark’s book defends the philosophical idea that mind itself leaks into the world. The core argument is really “Well, why not?” Worldly activity with cognitive scaffolding accomplishes many of the same ends as neural computation and evidently saves the brain a lot of bother, so why not let the mind be where the work is done? In particular, philosophical views about beliefs, regarding both what they are and how they fit in the life of the mind, seem neutral about where a belief is located. It might be spread among the synapses, or on a microchip hardwired into the brain, or in a handy notebook—any of those media could preserve all the features of the belief. Critics search for some “mark of the mental” that will keep thinking inside the skull, but Clark counters that in some cases these lines in the sand are the result of mistaken analyses of the mental, and in other instances, they are lines easily crossed by extended minds.
Alva Noë’s target is consciousness, and in broad terms his position is compatible with Clark’s. Noë writes that in Out of Our Heads his central claim is that to understand consciousness—the fact that we think and feel and that a world shows up for us—we need to look at a larger system of which the brain is only one element. Consciousness is not something the brain achieves on its own. Consciousness requires the joint operation of brain, body, and world. Indeed, consciousness is an achievement of the whole animal in its environmental context. I deny, in short, that you are your brain.
Even in this passage we see an ambiguity that runs throughout the book. (Unlike Noë’s thoughtful and thorough Action in Perception [The MIT Press, 2004], Out of Our Heads is a manifesto of hyperbolic claims resting on sketches of argument.) Is it that we are not merely our brains (which is Clark’s view as well), or that we are not our brains at all? How completely “out of our heads” are we? The radical possibility runs through passages like this one, in which Noë describes what he refers to as a “sensorimotor, enactive, or actionist approach”:
Seeing is not something that happens in us. It is not something that happens to us or in our brains. It is something we do. It is an activity of exploring the world making use of our practical familiarity with the ways in which our own movement drives and modulates our sensory encounter with the world. Seeing is a kind of skillful activity.
This theory of perception has strong echoes of J. J. Gibson’s “ecological approach” to perception, along with the embodied phenomenology of Maurice Merleau-Ponty. Seeing is certainly skillful activity, but is that activity mediated by anything like an inner representation, or by a state of conscious awareness that either guides the activity or results from it? Noë repeatedly edges toward elimination of inner states, only to hedge:
We ourselves are distributed, dynamically spread-out, world-involving beings. We are not world representers. We have no need for that idea. To put the point in a provocative way, we are, in Merleau-Ponty’s memorable phrase, “empty heads turned toward the world.” And as a result of this, our worlds are not confined to what is inside us, memorized, represented. Much more is present to us than is immediately present. We live in extended worlds where much is present virtually, thanks to our skills and to technology.
We have no need for representation—at all? Or is it that our worlds are not confined to what is inside us, those innards nonetheless enacting cognitive, computational and conscious processes?
There is much to be gained by recognizing the intricate embedding of consciousness in the body and the world. Cognitive science (including the study of consciousness) has been shackling itself with its brainbound assumptions. Consciousness depends on its embodied embedding, but should it be identified entirely with the myriad couplings and loops the brain surely exploits?
This question is in play between Clark and Noë. Each disputes the other in passing. For Clark, one of the distinctive features of conscious awareness is the capacity to disengage from enacted specifics. Driving a car, for example, requires precise enactive sensorimotor coupling for beginners and experts alike, but for the practiced driver the details drop out of awareness. Noë’s view identifies consciousness with all the activities of the extended mind and thus implies that skilled enactors remain aware of everything engaged by their performance.
Clark also enlists clever experiments and reports of brain deficits that suggest a dissociation of awareness from sensorimotor knowledge. Familiar optical illusions make objects that are in fact identical look as though they differ in size, but when one reaches to grasp them, one’s fingers open to the same (correct) extent regardless of context. The eye-to-hand loop is not fooled by appearances, however things may seem to the conscious mind. Similarly, some brain lesions can impair the ability to describe a scene while sparing the capacity for fluent sensorimotor interaction, whereas other lesions have the opposite result. Thus there seem to be two partially distinct systems, one mediating fluent behavior and the other generating the model of the world available to consciousness.
From Noë’s point of view, to supersize the mind while leaving consciousness inside the head seems arbitrary, if not fainthearted. Any such distinction regards one fantastically complex information processing system as conscious, while declaring another, equally complex system, not. What’s the difference?
An expansive, totalized theory of consciousness like Noë’s solves the problem by dissolving it:
The problem of consciousness, then, is none other than the problem of life. What we need to understand is how life emerges in the natural world.
Descartes framed the modern mind with a sentence beginning “I am . . . ,” launching centuries of debate about how to complete the thought. But until now, that first-person grammatical form has been the eye of the storm, a nexus of subjectivity to which a world appears. In a truly post-Cartesian world of looping, evanescent, chattering, clattering networks, the problem of consciousness may simply disappear. The sum may turn out to be less than the whole of its parts.
Dan Lloyd is the Thomas C. Brownell Professor of Philosophy at Trinity College, Connecticut. He is the author of Radiant Cool: A Novel Theory of Consciousness (The MIT Press, 2004) and is currently working on a book-length philosophical dialogue titled Ghosts in the Machine.
In today’s world we are expected to be busy all the time. We are expected to work long hours and chase from one place to another. Being stressed seems to have become a lifestyle choice, in fact possibly a status symbol.
After all , those who cannot complain of high stress levels can’t possibly be successful. So to be part of the in-group better we join the I-don’t-know-how-to-relax set.
But be careful before buying into that way of life. It seems that not only actual stress but even just our perceptions of being stressed may lead to premature aging and disease.
Over the years a number of scientific studies have shown a link between chronic psychological stress and conditions such as cardiovascular disease and weakened immune function but until recently the exact mechanisms by which stress influences disease processes was unknown.
In 2004 Science Daily reported that although a study published in the November issue of Proceedings of the National Academy of Sciences, a UCSF-led team reported that psychological stress may exact its toll, at least in part, by affecting molecules believed to play a key role in cellular aging and possibly, disease development.
The team determined that chronic stress, and the perception of life stress, each had a significant impact on particular DNA-protein complexes called telomeres that promote genetic stability. Telomeres play a critical role in determining the number of times a cell divides, its health, and its life span.
Previous studies have shown that an enzyme within the cell, called telomerase, keeps immune cells young by preserving their telomere length and ability to continue dividing. Short telomeres are linked to a range of human diseases, including HIV, osteoporosis, heart disease and aging.
The UCSF study involved 58 women between the ages of 20 and 50, all of whom were biological mothers either of a chronically ill child (39 women, so-called "caregivers") or a healthy child (19 women, or "controls").
One of the most important findings of the study was that the perception of being stressed proved to have the same effects on the body as actual stress. According to Science Daily “the most striking result, (showed that) the telomeres of women with the highest perceived psychological stress - across both groups - had undergone the equivalent of approximately 10 years of additional aging, compared with the women across both groups who had the lowest perception of being stressed. The highest-stress group also had significantly decreased telomerase activity and higher oxidative stress than the lowest-stress group.”
According to co-author Elizabeth Blackburn, PhD, Morris Herzstein Professor of Biology and Physiology in the Department of Biochemistry and Biophysics at UCSF the study provided the first evidence that chronic psychological stress and the way a person perceives stressmay change the rate of cellular aging.
Lead author Elissa Epel, PhD, UCSF assistant professor of psychiatry states that these findings “suggests a cellular mechanism for how chronic stress may cause premature onset of disease. … Chronic stress appears to have the potential to shorten the life of cells, at least immune cells."
But how does stress negatively influence the workings of telomerase causing people to be more susceptible to disease?
The answer came in 2008 when UCLA scientists found that the stress hormone cortisol suppresses immune cells' ability to activate their telomerase. This may explain why the cells of persons under chronic stress have shorter telomeres.
When stressed the levels of cortisol in the body rises to support a "fight or flight" response. If the hormone remains elevated in the bloodstream for long periods of time, though, it wears down the immune system.
How you answer questions like these, it turns out, may determine how long it will take for you to decipher what you're reading, solve your puzzle, or get your keys back.
The brain is often envisioned as something like a computer, and the body as its all-purpose tool. But a growing body of new research suggests that something more collaborative is going on - that we think not just with our brains, but with our bodies. A series of studies, the latest published in November, has shown that children can solve math problems better if they are told to use their hands while thinking. Another recent study suggested that stage actors remember their lines better when they are moving. And in one study published last year, subjects asked to move their eyes in a specific pattern while puzzling through a brainteaser were twice as likely to solve it.
The term most often used to describe this new model of mind is "embodied cognition," and its champions believe it will open up entire new avenues for understanding - and enhancing - the abilities of the human mind. Some educators see in it a new paradigm for teaching children, one that privileges movement and simulation over reading, writing, and reciting. Specialists in rehabilitative medicine could potentially use the emerging findings to help patients recover lost skills after a stroke or other brain injury. The greatest impact, however, has been in the field of neuroscience itself, where embodied cognition threatens age-old distinctions - not only between brain and body, but between perceiving and thinking, thinking and acting, even between reason and instinct - on which the traditional idea of the mind has been built.
"It's a revolutionary idea," says Shaun Gallagher, the director of the cognitive science program at the University of Central Florida. "In the embodied view, if you're going to explain cognition it's not enough just to look inside the brain. In any particular instance, what's going on inside the brain in large part may depend on what's going on in the body as a whole, and how that body is situated in its environment."
The emerging field builds on decades of research into human movement and gesture. Much of the earlier work looked at the role of gestures in communication, asking whether gesture grew out of speech or exploring why people gestured when they were talking on the telephone.
But today, neuroscientists, linguists, and philosophers are making much bolder claims. A few argue that human characteristics like empathy, or concepts like time and space, or even the deep structure of language and some of the most profound principles of mathematics, can ultimately be traced to the idiosyncrasies of the human body. If we didn't walk upright, for example, or weren't warm-blooded, they argue, we might understand these concepts totally differently. The experience of having a body, they argue, is intimately tied to our intelligence.
"If you want to teach a computer to play chess, or if you want to design a search engine, the old model is OK," says Rolf Pfeifer, director of the artificial intelligence lab at the University of Zurich, "but if you're interested in understanding real intelligence, you have to deal with the body."
Embodied cognition upends several centuries of thinking about thinking. Rene Descartes, living in an age when steam engines were novelty items, envisioned the brain as a pump that moved "animating fluid" through the body - head-shrinkers through the ages have tended to enlist the high-tech of their day to describe the human cognitive system - but the mind, Descartes argued, was something else entirely, an incorporeal entity that interacted with the body through the pineal gland.
While a few thinkers, most notably the French philosopher Maurice Merleau-Ponty in the 1940s, challenged Descartes' mind-body separation, it remained the dominant model up through the 20th century, though its form evolved with the times. After the development of the modern computer in the years after World War II, a new version of the same model was adopted, with the brain as a computer and the mind as the software that ran on it.
In the 1980s, however, a group of scholars began to contest this approach. Fueled in part by broad disappointment with artificial-intelligence research, they argued that human beings don't really process information the way computers do, by manipulating abstract symbols using formal rules. In 1995, a major biological discovery brought even more enthusiasm to the field. Scientists in Italy discovered "mirror neurons" that respond when we see someone else performing an action - or even when we hear an action described - as if we ourselves were performing the action. By simultaneously playing a role in both acting and thinking, mirror neurons suggested that the two might not be so separate after all.
"You were seeing the same system, namely the motor system, playing a role in communication and cognition," says Arthur Glenberg, a professor of psychology and head of the embodied cognition laboratory at ArizonaStateUniversity.
This realization has driven much of the recent work looking at how moving and thinking inform and interfere with each other. For example, a pair of studies published in 2006 by Sian Beilock, now an assistant professor of psychology at the University of Chicago, and Lauren Holt, one of her former students, examined how people who were good at certain physical activities thought about those activities.
In one study, Beilock and Holt had college hockey players, along with a non-hockey-player control group, read a sentence, sometimes hockey-related, sometimes not. Then the subjects would be shown a picture and asked if it corresponded with the sentence. Hockey players and non-hockey players alike almost invariably answered correctly, but on the hockey-related sentences the response times of the hockey players were significantly faster than the non-players. In a second study, the researchers found similar results with football players. According to Beilock, the difference in response time wasn't a matter of knowledge - after all, all of the subjects in the study got the vast majority of the questions right. What it suggested, Beilock argues, is that the athletes' greater store of appropriate physical experiences served as a sort of mental shortcut.
"People with different types of motor experiences think in different ways," she argues.
These sorts of results aren't simply limited to thinking about sports, or other highly physical activities.
A 2003 study by Michael Spivey, a psychology professor at Cornell, and his student Elizabeth Grant, found that people who were given a tricky spatial relations brainteaser exhibited a distinctive and unconscious pattern of eye movements just before they arrived at the answer. The subjects seemed to unconsciously work through the problem by enacting possible solutions with their gaze.
A study published in August by Alejandro Lleras and Laura Thomas, two psychologists at the University of Illinois, built on those results by inducing the eye movements Spivey had discovered. Lleras and Thomas found that doing so greatly improved the rate at which people solved the problem - even though most never figured out that the eye movements had anything to do with it.
"The subjects actually think that the eye-tracking task is very distracting," Lleras says. "They think we're doing this to keep them from solving the problem."
Other studies have looked at non-spatial problems and at memory. Work led by Susan Goldin-Meadow, a psychology professor at the University of Chicago, has found that children given arithmetic problems that normally would be too difficult for them are more likely to get the right answer if they're told to gesture while thinking. And studies by Helga Noice, a psychologist at ElmhurstCollege, and her husband Tony Noice, an actor and director, found that actors have an easier time remembering lines their characters utter while gesturing, or simply moving.
The body, it appears, can subtly shape people's preferences. A study led by John Cacioppo, director of the Center for Cognitive and Social Neuroscience at the University of Chicago, found that subjects (all non-Chinese speakers) shown a series of Chinese ideographs while either pushing down or pulling up on a table in front of them will say they prefer the ideographs they saw when pulling upward over the ones they saw while pushing downward. Work by Beilock and Holt found that expert typists, when shown pairs of two-letter combinations and told to pick their favorite, tend to pick the pairs that are easier to type - without being able to explain why they did so.
What's particularly interesting to neuroscientists is the role that movement seems to play even in abstract thinking. Glenberg has done multiple studies looking at the effect of arm movements on language comprehension. In Glenberg's work, subjects were asked to determine whether a string of words on a computer screen made sense. To answer they had to reach toward themselves or away from themselves to press a button.
What Glenberg has found is that subjects are quicker to answer correctly if the motion in the sentence matches the motion they must make to respond. If the sentence is, for example, "Andy delivered the pizza to you," the subject is quicker to discern the meaning of the sentence if he has to reach toward himself to respond than if he has to reach away. The results are the same if the sentence doesn't describe physical movement at all, but more metaphorical interactions, such as "Liz told you the story," or "Anne delegates the responsibilities to you."
The implication, Glenberg argues, is that "we are really understanding this language, even when it's more abstract, in terms of bodily action."
Some linguists, cognitive scientists, and philosophers go further - arguing that the roots of even the most complex and esoteric aspects of human thought lie in the body. The linguist George Lakoff, of the University of California, Berkeley, along with Rafael Nunez, a cognitive scientist at the University of California, San Diego, have for several years advanced the argument that much of mathematics, from set theory to trigonometry to the concept of infinity, derives not from immutable properties of the universe but from the evolutionary history of the human brain and body. Our number system, they argue, and our understanding of addition and subtraction emerge from the fact that we are bipedal animals that measure off distances in discrete steps.
"If we had wheels, or moved along the ground on our bellies like snakes," Lakoff argues, "math might be very different."
These ideas have met intense opposition among mathematicians, but also among some cognitive scientists, who believe they reflect an overreaching reading of a promising but still sketchy set of experimental results.
"I think these findings are really fantastic and it's clear that there's a lot of connection between mind and body," says Arthur Markman, a professor of psychology at the University of Texas. He remains skeptical, though, that the roots of higher cognition will be found in something as basic as the way we walk or move our eyes or arms.
"Any time there's a fad in science there's a tendency to say, 'It's all because of this,"' Markman says. "But the thing in psychology is that it's not all anything, otherwise we'd be done figuring it out already."
While embodied cognition remains a young field, some specialists believe that it suggests a rethinking of how we approach education. Angeline Lillard, a psychology professor at the University of Virginia, says that one possibility is to take another look at the educational approach that Italian educator Maria Montessori laid out nearly 100 years ago, theories that for decades were ignored by mainstream educators. A key to the Montessori method is the idea that children learn best in a dynamic environment full of motion and the manipulation of physical objects. In Montessori schools, children learn the alphabet by tracing sandpaper letters, they learn math using blocks and cubes, they learn grammar by acting out sentences read to them.
To Lillard, the value of embodied cognition in education is self-evident.
"Our brains evolved to help us function in a dynamic environment, to move through it and find food and escape predators," she says. "It didn't evolve to help us sit in a chair in a classroom and listen to someone and regurgitate information."
