A non-invasive brain-machine interface?

Waldert et al. show that hand movement direction can be decoded from magneto- (MEG) and electro-(EEG) encephalography recordings. They suggest that this might make it possible to design a non-invasive brain machine interface. Here is their abstract:

Brain activity can be used as a control signal for brain–machine interfaces (BMIs). A powerful and widely acknowledged BMI approach, so far only applied in invasive recording techniques, uses neuronal signals related to limb movements for equivalent, multidimensional control of an external effector. Here, we investigated whether this approach is also applicable for noninvasive recording techniques. To this end, we recorded whole-head MEG during center-out movements with the hand and found significant power modulation of MEG activity between rest and movement in three frequency bands: an increase for ≤7 Hz (low-frequency band) and 62–87 Hz (high-{gamma} band) and a decrease for 10–30 Hz (β band) during movement. Movement directions could be inferred on a single-trial basis from the low-pass filtered MEG activity as well as from power modulations in the low-frequency band, but not from the β and high-{gamma} bands. Using sensors above the motor area, we obtained a surprisingly high decoding accuracy of 67% on average across subjects. Decoding accuracy started to rise significantly above chance level before movement onset. Based on simultaneous MEG and EEG recordings, we show that the inference of movement direction works equally well for both recording techniques. In summary, our results show that neuronal activity associated with different movements of the same effector can be distinguished by means of noninvasive recordings and might, thus, be used to drive a noninvasive BMI.

Creating new worlds - science and fiction as the same thing

Alison Gopnik has an interesting take on why children pretend much of the time and spend time in imaginary worlds:

Recently, I've had to change my mind about the very nature of knowledge because of an obvious, but extremely weird fact about children - they pretend all the time. Walk into any preschool and you'll be surrounded by small princesses and superheroes in overalls - three-year-olds literally spend more waking hours in imaginary worlds than in the real one. Why? Learning about the real world has obvious evolutionary advantages and kids do it better than anyone else. But why spend so much time thinking about wildly, flagrantly unreal worlds? The mystery about pretend play is connected to a mystery about adult humans - especially vivid for an English professor's daughter like me. Why do we love obviously false plays and novels and movies?

The greatest success of cognitive science has been our account of the visual system. There's a world out there sending information to our eyes, and our brains are beautifully designed to recover the nature of that world from that information. I've always thought that science, and children's learning, worked the same way. Fundamental capacities for causal inference and learning let scientists, and children, get an accurate picture of the world around them - a theory. Cognition was the way we got the world into our minds.

But fiction doesn't fit that picture - its easy to see why we want the truth but why do we work so hard telling lies? I thought that kids' pretend play, and grown-up fiction, must be a sort of spandrel, a side-effect of some other more functional ability. I said as much in a review in Science and got floods of e-mail back from distinguished novel-reading scientists. They were all sure fiction was a Good Thing - me too, of course, - but didn't seem any closer than I was to figuring out why.

So the anomaly of pretend play has been bugging me all this time. But finally, trying to figure it out has made me change my mind about the very nature of cognition itself.

I still think that we're designed to find out about the world, but that's not our most important gift. For human beings the really important evolutionary advantage is our ability to create new worlds. Look around the room you're sitting in. Every object in that room - the right angle table, the book, the paper, the computer screen, the ceramic cup was once imaginary. Not a thing in the room existed in the pleistocene. Every one of them started out as an imaginary fantasy in someone's mind. And that's even more true of people - all the things I am, a scientist, a philosopher, an atheist, a feminist, all those kinds of people started out as imaginary ideas too. I'm not making some relativist post-modern point here, right now the computer and the cup and the scientist and the feminist are as real as anything can be. But that's just what our human minds do best - take the imaginary and make it real. I think now that cognition is also a way we impose our minds on the world.

In fact, I think now that the two abilities - finding the truth about the world and creating new worlds-are two sides of the same coins. Theories, in science or childhood, don't just tell us what's true - they tell us what's possible, and they tell us how to get to those possibilities from where we are now. When children learn and when they pretend they use their knowledge of the world to create new possibilities. So do we whether we are doing science or writing novels. I don't think anymore that Science and Fiction are just both Good Things that complement each other. I think they are, quite literally, the same thing.

The Best Men Are (Not Always) Already Taken

Bressan1 and Stranieri take a (dubious) evolutionary psychological approach to the question of female preference for single versus attached males. The outcome is interesting. Here is their abstract:

Because men of higher genetic quality tend to be poorer partners and parents than men of lower genetic quality, women may profit from securing a stable investment from the latter, while obtaining good genes via extrapair mating with the former. Only if conception occurs, however, do the evolutionary benefits of such a strategy overcome its costs. Accordingly, we predicted that (a) partnered women should prefer attached men, because such men are more likely than single men to have pair-bonding qualities, and hence to be good replacement partners, and (b) this inclination should reverse when fertility rises, because attached men are less available for impromptu sex than single men. In this study, 208 women rated the attractiveness of men described as single or attached. As predicted, partnered women favored attached men at the low-fertility phases of the menstrual cycle, but preferred single men (if masculine, i.e., advertising good genetic quality) when conception risk was high.

Painful or disgusting? - ask parietal and cingulate cortex

Benuzzi et al. find brain activity specific for disgusting scenes in the posterior cingulate cortex. Signal changes in perigenual cingulate and left anterior insula are linearly related to the perceived unpleasantness. Painful scenes selectively induce activation of left parietal foci including the parietal operculum, the postcentral gyrus, and adjacent portions of the posterior parietal cortex. Their abstract is here, and here is one figure from the paper:

Top, Cortical foci active during the observation of painful video clips. Bottom, Cortical foci active during the observation of disgusting video clips.

Are today's young people really more narcissistic?

A comment by Trzesniewski et al. on the idea that today's young people have inflated impressions of themselves compared with previous generations. They:

..investigated secular trends in narcissism and self-enhancement over the past three decades. Despite recent claims about the impact of the "self-esteem movement" on the current generation of young people, we found no evidence that college students' scores on the Narcissistic Personality Inventory increased from the 1980s through 2007 (N = 26,867), although we did find small changes in specific facets of narcissism. Similarly, we found no evidence that high school students' level of self-enhancement, defined by the discrepancy between their perceived intelligence and their actual academic achievements, increased from 1976 to 2006 (N = 410,527). These results cast doubt on the belief that today's young people have increasingly inflated impressions of themselves compared with previous generations.

100% accuracy in automatic face detection.

A problem with the automatic face recognition systems being tested in some airport security screening systems is that none can cope with the kind of image variability encountered in the real world. Jenkins and Burton have used a simple averaging technique to increase the accuracy of an industry standard face-recognition algorithm from 54% to 100%. They averaged the images from 20 different photographs for each of 25 male celebrities who were also in a large public online database of 31,077 photographs of famous faces, comprising an average of nine different photos for each of 3628 celebrities - these images were highly variable in their quality and covered a wide range of lighting conditions, facial expressions, poses, and age. Using the FaceVACS (Cognitec Systems GmbH, Dresden, Germany)industry standard face-recognition system that has been widely adopted, they fed this database their averaged images for each of 25 male celebrities who were also in the online database (excluding photos that were both in their sample and in the database). With the averaged images, the database returned the correct identification 100% of the time. When individual photographs were presented to the database the correct identification was returned only ~50% of the time. From their text:

We demonstrated this improvement with a commercially available algorithm and an online face database over which we had no control. We suggest that image averaging enhances performance by stabilizing the face image. With standard photographs, the match tends to be dominated by aspects of the image that are not diagnostic of identity (e.g., lighting and pose). Averaging together multiple photographs of the same person dilutes these transients while preserving aspects of the image that are consistent across photos. The resulting images capture the visual essence of an individual's face and elevate machine performance to the standard of familiar face recognition in humans. It would be technically straightforward to incorporate an average image into identification documents. Doing so would greatly reduce the incidence of face-recognition errors and raise the prospect of a viable automatic face-recognition infrastructure.


Example photographs of Bill Clinton and their average (right). [Image 1, photo by Marc Nozell (www.flickr.com/photos/marcn/534512066); image 2, photo by Roger Goun (www.flickr.com/photos/sskennel/829574139); image 20, photo by Nelson Pavlosky (www.flickr.com/photos/skyfaller/26752190). All photos were used under a Creative Commons license.] Different pictures of a single face can vary enormously, making automatic recognition difficult. Averaging together multiple photos of the same face stabilizes the image, improving performance dramatically.

Need an antidepressant?

Could a presidential debate on science backfire?

An interesting essay by David Goldston argues that a debate on science by presidential candidates might do more harm than good.

Sharing posts, bookmarking, related content, etc.

My friend Kelly Doering who does internet consulting and website design, has just helped me dink around a bit with the mechanics of MindBlog. You will now notice a single icon after each post that lets you bookmark or share a post using more than 30 of the major services like StumbleUpon, Reddit, Del.icio.us, Reddit, etc. If you haven't already, you should try the sphere:related content link that may appear just below the bookmark icon with a post that interests you. It sometimes does a very nice job of bringing up related material on other websites.

Your brain is shrinking sooner than you thought...

Here is a chilling little item from Pieperhoff et al., who examined MRI images of the brains of 51 healthy male subjects from 18 to 51 years old. They found age-related volume declines in circumscribed brain regions: the sensorimotor system, encompassing the cerebellum, thalamus, somatosensory and motor cortices, and the prefrontal system, encompassing the anterior cingulate as well as the lateral and basomedial frontal cortices. Regions belonging to other functional systems, such as the auditory system or the visual system, did not show such age–volume relationships.

Horizontal sections of the reference brain with statistical maps, showing the t values of age-related volume decline and increase. t values were calculated by a two-sided t test for a linear regression in the voxels of the LVR maps, depending on age.

The incubator of suicide attacks - Fictive Kinship

Anthropologist Scott Atran (Author of "In Gods We Trust") writes an essay laying out his change of mind about why people are willing to die for a cause. He has moved from thinking that individual cognition and personality, influences from broad socio-economic factors, and degree of devotion to religious or political ideology were determinant, to seeing friendship and others aspects of small group dynamics, especially acting together, trumping most everything else.

...people don't kill and die simply for a cause. They do it for friends — campmates, schoolmates, workmates, soccer buddies, body-building buddies, pin-ball buddies — who share a cause. Some die for dreams of jihad — of justice and glory — but nearly all in devotion to a family-like group of friends and mentors, of "fictive kin." (Atran gives a number of explicit examples of such groups)

... it is no accident that nearly all religious and political movements express allegiance through the idiom of the family — Brothers and Sisters, Children of God, Fatherland, Motherland, Homeland, and the like. Nearly all such movements require subordination, or at least assimilation, of any real family (genetic kinship) to the larger imagined community of "Brothers and Sisters." Indeed, the complete subordination of biological loyalty to ideological loyalty for the Ikhwan, the "Brotherhood" of the Prophet, is Islam's original meaning, "Submission."
...Social psychology tends to support the finding that "groupthink" often trumps individual volition and knowledge, whether in our society or any other. But for Americans bred on a constant diet of individualism the group is not where one generally looks for explanation.

Back in Wisconsin....

I am SO grateful that I am able to be a snowbird, now in Ft. Lauderdale. Here is a picture of my home in Wisconsin, where more snow has fallen this winter than in any year since recordings of snowfall began in the 19th century.

MindBlog's second anniversary

I just realized that today is MindBlog's second anniversary. It is hard for me to believe that there have been 902 postings since Feb. 8, 2006. Back then I had just read an article in the New York Times on the rising blogging fad and thought to myself, "Since I am reading and thinking about all this stuff anyway, I might as well take the small extra effort to clean it up a bit and present it." The extra effort turns out to be not so small. The number of subscribers to the MindBlog feed has risen to over 400, and on a given day there are 300-1,500 views of individual postings. Being a borderline (or maybe not even borderline) obsessive-compulsive, I've become yoked to the lockstep production of at least two blog postings a day. The retired professor isn't feeling all that retired..... Anyway, I am grateful for the kind emails I have received, and I've enjoyed responding to requests for further analysis or information.

Middle Age Misery

Blanceflower and Oswald have done a fascinating study (PDF here) showing that across cultures, from Azerbaijan to Zimbabwe, we are happiest towards the beginning and end of our lives, leaving us most miserable in middle years between 40 and 50. For both men and women in the UK, the probability of depression peaked at around the age of 44. In the US, men were most likely to be unhappiest at 50, while for women the age was 40. The cause of the apparent U-shaped curve is not known. Quoting Oswald (the graphic is from his website):

...one possibility is that individuals learn to adapt to their strengths and weaknesses, and in mid-life quell their infeasible aspirations. Another possibility is that cheerful people live systematically longer...A third possibility is that older people might compare their lives with their peers'. Seeing their friends die could mean people value their remaining years more highly...It looks from the data like something happens deep inside humans. For the average person in the modern world, the dip in mental health and happiness comes on slowly, not suddenly in a single year...Only in their 50s do most people emerge from the low period. But encouragingly, by the time you are 70, if you are still physically fit then on average you are as happy and mentally healthy as a 20-year-old. Perhaps realising that such feelings are completely normal in mid-life might even help individuals survive this phase better.

The World in the Brain

Here are a few excerpts from a brief essay by Steve Kosslyn in the Edge.org series "What have you changed your mind about?

There is a really elegant solution to the problem that the genes can't know in advance how far apart the eyes will be. To cope with this problem, the genes overpopulate the brain, giving us options for different environments (where the distance between eyes and length of the arms are part of the brain's "environment," in this sense), and then the environment selects which connections are appropriate, and the useless connections are pruned away. In other words, the genes take advantage of the environment to configure the brain.

This overpopulate-and-select mechanism is not limited to stereovision. In general, the environment sets up the brain (above and beyond any role it may have had in the evolution of the species), configuring it to work well in the world a person inhabits. And by environment I'm including everything outside the brain — including the social environment. For example, it's well known that children can learn multiple languages without an accent and with good grammar, if they are exposed to the language before puberty. But after puberty, it's very difficult to learn a second language so well.

This perspective leads me to wonder whether we can assume that the brains of people living in different cultures process information in precisely the same ways. Yes, people the world over have much in common (we are members of the same species, after all), but even small changes in the wiring may lead us to use the common machinery in different ways. If so, then people from different cultures may have unique perspectives on common problems, and be poised to make unique contributions toward solving such problems... to understand how any specific brain functions, we need to understand how that person was raised, and currently functions, in the surrounding culture.

A similar, more brief, response to the edge.org question was offered by Jeffrey Epstein, A science Philanthropist:

The question presupposes a well defined "you", and an implied ability that is under "your" control to change your "mind". The "you" I now believe is distributed amongst others (family friends , in hierarchal structures,) i.e. suicide bombers, believe their sacrifice is for the other parts of their "you". The question carries with it an intention that I believe is out of one's control. My mind changed as a result of its interaction with its environment. Why? because it is a part of it.

Nicholas Humphrey on consciousness...

I have always admired Nicholas Humphrey's perspectives on sensing and consciousness, and referenced his ideas on evolution of the nervous system in my Biology of Mind book. He has now written a nice essay in Seed Magazine, and I strongly recommend that you read it. He argues against the idea:

...that consciousness must be helping us do something that we can do only by virtue of being conscious, in the way that, say, a bird can fly only because it has wings, or you can understand this sentence only because you know English.

Rather,

...I want to suggest the role of phenomenal consciousness may not be like this at all. Its role may not be to enable us to do something we could not do otherwise, but rather to encourage us to do something we would not do otherwise: to make us take an interest in things that otherwise would not interest us, or to mind things we otherwise would not mind, or to set ourselves goals we otherwise would not set.

I will not hold back from telling you my own main conclusion from a lifetime's interest in what consciousness does. I may shock you by what may seem the naivety of my conclusion (I've shocked myself): I think the plain and simple fact is that consciousness—on various levels—makes life more worth living.

We like being phenomenally conscious. We like the world in which we're phenomenally conscious. We like ourselves for being phenomenally conscious. And the resulting joie de vivre, the enchantment with the world we live in, and the enhanced sense of our own metaphysical importance have, in the course of evolutionary history, turned our lives around.

Added note 11/16/08: I just found a later published version of this article. PDF here.

Evolutionary psychology on steroids...

Here are Steven Pinker's comments on recent data showing that the human genome has undergone strong recent selection, rendering invalid evolutionary psychology's initial assumption that human evolution halted 10,000 - 50,000 years ago.

New results from the labs of Jonathan Pritchard, Robert Moyzis, Pardis Sabeti, and others have suggested that thousands of genes, perhaps as much as ten percent of the human genome, have been under strong recent selection, and the selection may even have accelerated during the past several thousand years. The numbers are comparable to those for maize, which has been artificially selected beyond recognition during the past few millennia.

If these results hold up, and apply to psychologically relevant brain function (as opposed to disease resistance, skin color, and digestion, which we already know have evolved in recent millennia), then the field of evolutionary psychology might have to reconsider the simplifying assumption that biological evolution was pretty much over and done with 10-000 — 50,000 years ago.

And if so, the result could be evolutionary psychology on steroids. Humans might have evolutionary adaptations not just to the conditions that prevailed for hundreds of thousands of years, but also to some of the conditions that have prevailed only for millennia or even centuries. Currently, evolutionary psychology assumes that any adaptation to post-agricultural ways of life are 100% cultural.

Though I suspect some revisions will be called for, I doubt they will be radical, for two reasons. One is that many aspects of the human (and ape) environments have been constant for a much longer time than the period in which selection has recently been claimed to operate. Examples include dangerous animals and insects, toxins and pathogens in spoiled food and other animal products, dependent children, sexual dimorphism, risks of cuckoldry and desertion, parent-offspring conflict, risk of cheaters in cooperation, fitness variation among potential mates, causal laws governing solid bodies, presence of conspecifics with minds, and many others. Recent adaptations would have to be an icing on this cake -- quantitative variations within complex emotional and cognitive systems.

The other is the empirical fact that human races and ethnic groups are psychologically highly similar, if not identical. People everywhere use language, get jealous, are selective in choosing mates, find their children cute, are afraid of heights and the dark, experience anger and disgust, learn names for local species, and so on. If you adopt children from a technologically undeveloped part of the world, they will fit in to modern society just fine. To the extent that this is true, there can't have been a whole lot of uneven psychological evolution postdating the split among the races 50-100,000 years ago (though there could have been parallel evolution in all the branches).

Staying a Step Ahead of Aging

Being a person who exercises daily at moderate levels, the New York Times article with the title of this post was not a welcome read. It argues that blowing yourself away every few days is a better deal - i.e., that exercising intensely is more important than exercising often. I've always been suspicious of the 'no pain, no gain' school of exercise, thinking that while it might work for younger folks, it might not be taking enough account of potential long term inflammatory responses in people over 50.

Accurate visual movement without visual perception in normal subjects

An interesting article by Christensen et al. demonstrates blindsight in normal subjects:

Clinical cases of blindsight have shown that visually guided movements can be accomplished without conscious visual perception. Here, we show that blindsight can be induced in healthy subjects by using transcranial magnetic stimulation over the visual cortex. Transcranial magnetic stimulation blocked the conscious perception of a visual stimulus, but subjects still corrected an ongoing reaching movement in response to the stimulus. The data show that correction of reaching movements does not require conscious perception of a visual target stimulus, even in healthy people.

Here is part of their analysis:

It has been suggested that an important mechanism for the ability to perform fast corrections of goal-directed movement is an efference copy (i.e. a parallel signal indicating the expected sensory consequence of a motor command)... The argument is that the initial motor reaction time, when the subject reaches toward the first target, requires that the visual signal is processed via the visual cortex to motor regions of the brain. The advantage of an efference copy is that already at a very early point in the movement process any deviation in the performed movement from the intended movement can be adjusted. Hence, lower reaction time during the correction can be accomplished compared with the initial motor reaction time.

Furthermore, our results suggest that the mechanism responsible for fast visually guided corrective movements lies outside visual cortex and that the visual signals used for correction of movements bypass visual cortex. There may be subcortical routes for visually guided reaching that bypass the cortical regions affected by TMS.

Our left hemisphere is superior at perceiving global topology.

Most theories on how we extract visual information from our environment start with the sensible hierarchy of detecting features first and then integrating them to build objects. Li Chen and colleagues have also argued for the importance of extracting global topological properties as primitives in object perception, and they now have reported the intriguing discovery that the human visual system's sensitivity to topological properties is superior in the left hemisphere, at least for right-handers. Here is a graphic showing the basic conclusion of their work, from the commentary by He:

Figure - Schematic depiction of the left hemisphere's superiority in topological discrimination. A pair of shapes was briefly presented in either the right or the left visual field, projecting initially to the left or right hemispheres (LH or RH), respectively. Observers were asked to respond to whether the two shapes were the same or different. Although the triangle may appear more different from the disk than the ring does, human observers are more sensitive to the difference between the disk and the ring, which are topologically different, but are less sensitive to the difference between the triangle and the disk, which are topologically equivalent. Now, the authors show that the ability to discriminate topological differences is more superior in the left hemisphere than in the right hemisphere, as indicated by the bar plots showing the percent correct discrimination