Voluntary action is fundamental to human existence. Recent research suggests that volition involves a specific network of brain activity, centered on the fronto-median cortex. An important but neglected aspect of intentional action involves the decision whether to act or not. This decision process is crucial in daily life because it allows us to form intentions without necessarily implementing them. In the present study, we investigate the neural correlates of intentionally inhibiting actions using functional magnetic resonance imaging. Our data show that a specific area of the fronto-median cortex is more strongly activated when people prepare manual actions but then intentionally cancel them, compared with when they prepare and then complete the same actions. Our results suggest that the human brain network for intentional action includes a control structure for self-initiated inhibition or withholding of intended actions. The mental control of action has an enduring scientific interest, linked to the philosophical concept of "free will." Our results identify a candidate brain area that reflects the crucial decision to do or not to do.
Figure: A, Activation in the dFMC for the contrast of inhibition versus action trials. The z-map is thresholded at z > 3.09 (p <>
Friday, August 31, 2007
A cicada known as the kumazemi is descending on Japan en masse...cutting households off from their Internet. Apparently mistaking fibre-optic cables for withered branches, they have been punching their one-millimetre-diameter ovipositors into the cables and laying eggs. In at least 1,000 cases over the past two years, the cicadas have either severed the cable or opened up a hole, allowing water to seep in. The Osaka-based Nippon Telephone and Telegraph West Corporation has responded by creating new cables that lack the grooves that the cicadas target with their ovipositors ...
Thursday, August 30, 2007
Ponseti et al. suggest that they can observe a brain correlate of prenatal androgenization in homosexual women - they have less grey matter in their perirhinal cortex than heterosexual women. The article starts with a useful review of the controversial literature on previously suggested brain differences between homosexual and heterosexual individuals of the same sex. Here is their abstract and two figures:
Is sexual orientation associated with structural differences in the brain? To address this question, 80 homosexual and heterosexual men and women (16 homosexual men and 15 homosexual women) underwent structural MRI. We used voxel-based morphometry to test for differences in grey matter concentration associated with gender and sexual orientation. Compared with heterosexual women, homosexual women displayed less grey matter bilaterally in the temporo-basal cortex, ventral cerebellum, and left ventral premotor cortex. The relative decrease in grey matter was most prominent in the left perirhinal cortex. The left perirhinal area also showed less grey matter in heterosexual men than in heterosexual women. Thus, in homosexual women, the perirhinal cortex grey matter displayed a more male-like structural pattern. This is in accordance with previous research that revealed signs of sex-atypical prenatal androgenization in homosexual women, but not in homosexual men. The relevance of the perirhinal area for high order multimodal (olfactory and visual) object, social, and sexual processing is discussed.
Figure 1. Areas of increased GM concentration in heterosexual women compared to homosexual women. Coronal sections from y = 8 to y = −6 (p<0.05;>homosexual) was implicit masked with the contrast heterosexual (women>men). That way the intersection of significant voxels of both contrasts was gathered. As a result we found one cluster that matches both comparisons. That is, this brain area showed both, a lower GM concentration in heterosexual men compared to heterosexual women and a lower GM concentration in homosexual women relative to heterosexual women.
Figure 2. Heterosexual men and homosexual women compared to heterosexual women.
Areas of decreased GM concentration in heterosexual men are shown in blue and areas of decreased GM concentration in homosexual women are shown in yellow. Reduced GM concentration of homosexual women (relative to heterosexual women) is located within a sex dimorphic brain area.
Roughly 2% of humans suffer from obsessive compulsive disorder, but a lack of animal models has impeded research into this condition. Could a genetically engineered mouse model provide an exciting lead?And, a word of caution:
The mice studied by Welch et al. showed excessive grooming, which resulted in hair loss and skin injuries, as well as anxiety-like traits. These mice lack the gene encoding SAPAP3 — a scaffolding protein that is found in excitatory, glutamate-responsive synapses and is highly expressed only in the striatum region of the brain. The behavioural abnormalities in these mice were reversed by local expression of Sapap3 in the striatal region, which indicates that loss of this gene is responsible for the observed behavioural abnormalities.
The authors also found that a drug from the SSRI class — which selectively enhance serotonin-mediated neurotransmission throughout the brain — that is used to treat OCD in humans decreases both grooming and anxiety in these mice. This is interesting because a condition responsive to an enhancer of serotonin neurotransmission does not signify a primary defect in serotonin-mediated signalling; instead, the defect is in glutamate-responsive synapses. So alterations in serotonin seem to modulate glutamate action. These findings are also noteworthy because Welsh and colleagues have generated a possible mouse model of OCD. Moreover, these observations add to the accumulating, if circumstantial, evidence that OCD and its associated disorders result from abnormalities in neural circuits spanning the frontal, striatal and thalamic regions of the brain.
Even if we can gain assurance with additional research that the behaviours observed in Sapap3-deficient mice reflect abnormalities in circuits that produce human symptoms, we cannot assume that OCD-related conditions in humans involve variations in this gene. These disorders, like other major psychiatric diseases, seem to be heterogeneous with complex underpinnings — probably involving several genes — that, in interaction with developmental and environmental factors, could lead to abnormalities in frontal–striatal–thalamic circuits.
Wednesday, August 29, 2007
Many substances interfere with memory, as any hung-over partygoer can attest. But although booze and drugs can disrupt the making of new memories (such as the embarrassing antics at last night's party), they leave older memories intact. Neuroscientists think this is because, after a time, memories become wired into the brain in a way that makes them harder to wipe out: Long-term memories, in the generally accepted view, are maintained by structural changes to the synaptic connections between neurons.
The study [by Shama et al.] adds to other recent evidence that may challenge, or at least complicate, this view. A team of neuroscientists reports that injecting a drug that blocks an enzyme called protein kinase Mzeta (PKMzeta) into the cerebral cortex of rats makes the animals forget a meal that made them sick weeks earlier. The findings suggest that the continuing activity of PKMzeta is somehow necessary to maintain long-term memory, something that's not predicted by most current hypotheses on the mechanisms of memory. The work also hints at the possibility of future drugs that could tinker with memory--for therapeutic uses or for boosting brainpower.
"This is a somewhat mind-blowing conclusion," says David Glanzman, a neuroscientist at the University of California, Los Angeles. Enzymes similar to PKMzeta are known to be important in early stages of memory formation, Glanzman says, but most researchers had thought that these compounds were not needed to sustain memory once synaptic changes--such as the growth of new synapses or the strengthening of existing ones--had occurred.
...Going forward, it will be important to figure out how specific ZIP's memory-erasing effects are, says Lynn Nadel, a neuroscientist at the University of Arizona in Tucson. "It's possible that ZIP erases all learning, no matter how old," Nadel says. But if the drug works more selectively, it could one day have clinical applications, he says. For example, researchers and clinicians have been looking for compounds capable of eliminating the painful memories of trauma survivors (Science, 2 April 2004, p. 34). The flip side is cognitive enhancement, adds Richard Morris, a neuroscientist at the University of Edinburgh, U.K. "The next step might be to find out whether augmenting the action of PKMzeta can help sustain memories for longer than occurs normally."
As we grow from infancy to adulthood, specific connections (synapses) between nerve cells are formed, and excess connections pruned away. Approximately 40% of the connections (synapses) between nerve cells in our brains disappear during development. How does a nerve cell decide which synapses to destroy? Din et al., studying the nematode Caenorhabditis elegans provide evidence that the creation of adult synapses triggers the destruction of developmentally transient synapses forged by the same neuron. David Miller offers a summary figure in his review showing the molecular details of how a primary synapse region matures while a secondary synapse region is eliminated.
Disconnections (Click to enlarge). (Top) The developing HSNL motor neuron initially forms synapses with vulval muscles and motor neurons in two locations. (Bottom) The protein SYG-1 blocks proteolysis of synaptic proteins at primary synapses but allows destruction of secondary synapses. E2, E2 ubiquitin conjugating enzyme; RBX, Ring finger protein.
Tuesday, August 28, 2007
I've done several posts (for example here, here, and here) on how underlying brain processes might explain what have been taken to be paranormal experiences, particularly assuming part or all of one's body to be projected out into surrounding space. By now the evidence is overwhelming that our sense of of the location of our physical body can be projected in space wherever we wish. Sandra Blakeslee now comments (PDF here) on several recent very effective demonstrations of body projection in space reported in Science Magazine (here and here). You really should watch this video of one of the experiments from Blanke's group:
A friend pointed out this video to me. Fascinating. This is part I, which at its end links you on to the subsequent installments in the series.
Monday, August 27, 2007
I've done several postings on this already, but want to pass on George Johnson's excellent article in the Aug. 21 Science Section of the NYTimes about a session I attended given by Las Vegas Magicians for the recent meeting of the Association for the Scientific Study of Consciousness (PDF here).
An essay offered by Brad Buchsbaum on his blog.
Passing this on from MindHacks: an unknown man with a brain tattooed on the top of his head, revealed by a picture of a peeled back tuna can.
Friday, August 24, 2007
A collaboration at Washington University between Fair, Raichle, and others has offered a fascinating glimpse at how brain networks controlling our behavior develop from childhood through adolescence to adulthood. Here is their abstract, followed by two figures from the paper (PDF is here).
Human attentional control is unrivaled. We recently proposed that adults depend on distinct frontoparietal and cinguloopercular networks for adaptive online task control versus more stable set control, respectively. During development, both experience-dependent evoked activity and spontaneous waves of synchronized cortical activity are thought to support the formation and maintenance of neural networks. Such mechanisms may encourage tighter "integration" of some regions into networks over time while "segregating" other sets of regions into separate networks. Here we use resting state functional connectivity MRI, which measures correlations in spontaneous blood oxygenation level-dependent signal fluctuations between brain regions to compare previously identified control networks between children and adults. We find that development of the proposed adult control networks involves both segregation (i.e., decreased short-range connections) and integration (i.e., increased long-range connections) of the brain regions that comprise them. Delay/disruption in the developmental processes of segregation and integration may play a role in disorders of control, such as autism, attention deficit hyperactivity disorder, and Tourette's syndrome.
Fig. 2. (click to enlarge) Graphs formed from putative task-control regions in children, adolescents, and adults. ROI (regions of interest) locations are drawn to correspond to topographic brain locations. Right-sided ROIs are displayed on the right and anterior ROIs at the top of each graph. (A) rs-fcMRI revealed two separate control networks in adults as previously described (6). (B) The top 75 connections in adolescents revealed a similar two-component system as seen in adults; however, the dACC/msFC region was incorporated into the frontoparietal network. (C) The top 75 connections in children revealed a significant deviation from the adult architecture. The two networks were connected by a bridge connection (aPFC–dlPFC). The dACC/msFC region was incorporated into the frontoparietal network. Children lacked connections from the dlPFC to IPS and IPL. (D) Fit LOWESS curves of connection strength (r) versus age. As connection strength between the dACC/msFC region and the dF cortex decreased with age, correlation strength increased between the dACC/msFC and aI/fO regions. The aPFC region also decreased its connection strength with the dlPFC region with age but was already strongly connected to the aI/fO region in children. The strength of the aI/fO–aPFC connection was maintained into adulthood.
Fig. 3. (click to enlarge) Increased long-range and decreased short-range connectivity with age. Direct comparisons of all possible connections between adults and children were performed to test the statistical reliability of between-group differences. Both left- and right-hemisphere regions are placed on a transparent brain to aid with visualization. Red and blue lines highlight significant between-group differences for connections with an r ≥ 0.1 in either children or adults (i.e., absolute difference). Light blue and pink lines highlight connections present in both children and adults (r ≥ 0.1) that differed significantly in connection strength between groups (relative difference; P ≤ 0.05). (A) The segregation of the dACC/msFC region from the frontoparietal network (Fig. 2) was statistically significant, as was the disconnection of the aPFC from the dlPFC region (P ≤ 0.05). Most of the connections that "grew down" with age constituted short-range connections. Connections that "grew up" with age are faded to highlight this observation. (B) Connections between the dACC/msFC region and the cinguloopercular network that grew stronger with age were statistically significant (P ≤ 0.05). The connections of left dlPFC to left IPS and left frontal to left IPS were already present in children but significantly increased in strength with age. Most of the connections that "grew up" with age constituted long-range connections. Connections that "grew down" with age are faded to highlight this observation. Selected LOWESS curves are presented in A and B.
Thursday, August 23, 2007
Mark Lilla, Professor of the humanities at Columbia Univ., has generated an essay (adapted from his book "The Stillborn God: Religion, Politics and the Modern West") which appeared in the The New York Times Magazine of Aug. 19. It is beautifully written, focusing on Western political and religious history, and its interactions with Islam. I offer a few clips here:
The twilight of the idols has been postponed. For more than two centuries, from the American and French Revolutions to the collapse of Soviet Communism, world politics revolved around eminently political problems. War and revolution, class and social justice, race and national identity — these were the questions that divided us. Today, we have progressed to the point where our problems again resemble those of the 16th century, as we find ourselves entangled in conflicts over competing revelations, dogmatic purity and divine duty. We in the West are disturbed and confused. Though we have our own fundamentalists, we find it incomprehensible that theological ideas still stir up messianic passions, leaving societies in ruin. We had assumed this was no longer possible, that human beings had learned to separate religious questions from political ones, that fanaticism was dead. We were wrong.
The revival of political theology in the modern West is a humbling story. It reminds us that this way of thinking is not the preserve of any one culture or religion, nor does it belong solely to the past. It is an age-old habit of mind that can be reacquired by anyone who begins looking to the divine nexus of God, man and world to reveal the legitimate political order. This story also reminds us how political theology can be adapted to circumstances and reassert itself, even in the face of seemingly irresistible forces like modernization, secularization and democratization. Rousseau was on to something: we seem to be theotropic creatures, yearning to connect our mundane lives, in some way, to the beyond. That urge can be suppressed, new habits learned, but the challenge of political theology will never fully disappear so long as the urge to connect survives.
So we are heirs to the Great Separation only if we wish to be, if we make a conscious effort to separate basic principles of political legitimacy from divine revelation. Yet more is required still. Since the challenge of political theology is enduring, we need to remain aware of its logic and the threat it poses. This means vigilance, but even more it means self-awareness. We must never forget that there was nothing historically inevitable about our Great Separation, that it was and remains an experiment. In Europe, the political ambiguities of one religion, Christianity, happened to set off a political crisis that might have been avoided but wasn’t, triggering the Wars of Religion; the resulting carnage made European thinkers more receptive to Hobbes’s heretical ideas about religious psychology and the political implications he drew from them; and over time those political ideas were liberalized. Even then, it was only after the Second World War that the principles of modern liberal democracy became fully rooted in continental Europe.
As for the American experience, it is utterly exceptional: there is no other fully developed industrial society with a population so committed to its faiths (and such exotic ones), while being equally committed to the Great Separation. Our political rhetoric, which owes much to the Protestant sectarians of the 17th century, vibrates with messianic energy, and it is only thanks to a strong constitutional structure and various lucky breaks that political theology has never seriously challenged the basic legitimacy of our institutions. Americans have potentially explosive religious differences over abortion, prayer in schools, censorship, euthanasia, biological research and countless other issues, yet they generally settle them within the bounds of the Constitution. It’s a miracle.
...a number of Muslim thinkers around the world have taken to promoting a “liberal” Islam. What they mean is an Islam more adapted to the demands of modern life, kinder in its treatment of women and children, more tolerant of other faiths, more open to dissent. These are brave people who have often suffered for their efforts, in prison or exile, as did their predecessors in the 19th century, of which there were many. But now as then, their efforts have been swept away by deeper theological currents they cannot master and perhaps do not even understand. The history of Protestant and Jewish liberal theology reveals the problem: the more a biblical faith is trimmed to fit the demands of the moment, the fewer reasons it gives believers for holding on to that faith in troubled times, when self-appointed guardians of theological purity offer more radical hope. Worse still, when such a faith is used to bestow theological sanctification on a single form of political life — even an attractive one like liberal democracy — the more it will be seen as collaborating with injustice when that political system fails. The dynamics of political theology seem to dictate that when liberalizing reformers try to conform to the present, they inspire a countervailing and far more passionate longing for redemption in the messianic future. That is what happened in Weimar Germany and is happening again in contemporary Islam.
In the end, though, what happens on the opposite shore will not be up to us. We have little reason to expect societies in the grip of a powerful political theology to follow our unusual path, which was opened up by a unique crisis within Christian civilization. This does not mean that those societies necessarily lack the wherewithal to create a decent and workable political order; it does mean that they will have to find the theological resources within their own traditions to make it happen.
Our challenge is different. We have made a choice that is at once simpler and harder: we have chosen to limit our politics to protecting individuals from the worst harms they can inflict on one another, to securing fundamental liberties and providing for their basic welfare, while leaving their spiritual destinies in their own hands. We have wagered that it is wiser to beware the forces unleashed by the Bible’s messianic promise than to try exploiting them for the public good. We have chosen to keep our politics unilluminated by divine revelation. All we have is our own lucidity, which we must train on a world where faith still inflames the minds of men.
I'm not sure why I haven't mentioned these books, both appearing earlier this year. In "Train Your Mind, Change Your Brain: How a New Science Reveals Our Extraordinary Potential to Transform Ourselves" Wall Street Journal science writer Sharon Begley gives an account that derives largely from a 2004 meeting at MIT in Cambridge Mass (which I also enjoyed attending) in which the Dali Lama, Buddhist monks, and prominent neuroscientists exchanged insight and information. The book mentions work with meditation and mind training, as well as new approaches in treating dyslexia, depression, mental deterioration on aging, etc., but it is not a how-to manual.
The book by Norman Doidge, "The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science" gives stories of numerous examples of neuroplasticity and rehabilitation among his own patients, as well as relating other case studies of recovery and conversations with neuroscientists.
Wednesday, August 22, 2007
I've received four emails promoting a new book by B. Alan Wallace, a guy who has been the subject of two previous posts, one a positive review and abstracting of his book "The Attention Revolution," and the other more critical comments on a video presentation titled "Towards the first revolution in the mind sciences" he gave at a seminar for Google employees. That video presentation contains core ideas in his new book "Hidden Dimensions: The Unification of Physics and Consciousness (Columbia University Press, 2007)."
Below I give you the blurb on the book, and the problems I have with this are stated in the critical review just mentioned, some repeated below:
Bridging the gap between the world of science and the realm of the spiritual, B. Alan Wallace introduces a natural theory of human consciousness that has its roots in contemporary physics and Buddhism. Wallace’s "special theory of ontological relativity" suggests that mental phenomena are conditioned by the brain, but do not emerge from it. Rather, the entire natural world of mind and matter, subjects and objects, arises from a unitary dimension of reality that is more fundamental than these dualities, as proposed by Wolfgang Pauli and Carl Jung.My previous response:
To test his hypothesis, Wallace employs the Buddhist meditative practice of samatha, refining one’s attention and metacognition, to create a kind of telescope to examine the space of the mind. Drawing on the work of the physicist John Wheeler, he then proposes a more general theory in which the participatory nature of reality is envisioned as a self-excited circuit. In comparing these ideas to the Buddhist theory known as the Middle Way philosophy, Wallace explores further aspects of his "general theory of ontological relativity," which can be investigated by means of vipasyana, or insight, meditation. Wallace then focuses on the theme of symmetry in reference to quantum cosmology and the “problem of frozen time,” relating these issues to the theory and practices of the Great Perfection school of Tibetan Buddhism. He concludes with a discussion of the general theme of complementarity as it relates to science and religion.
The theories of relativity and quantum mechanics were major achievements in the physical sciences, and the theory of evolution has had an equally deep impact on the life sciences. Yet rigorous scientific methods do not yet exist to observe mental phenomena, and naturalism has its limits for shedding light on the workings of the mind. A pioneer of modern consciousness research, Wallace offers a practical and revolutionary method for exploring the mind that combines the keenest insights of contemporary physicists and philosophers with the time-honored meditative traditions of Buddhism.
The problem I think is that his analogy with other scientific revolutions fails on the issue of universality and ability to reproduce basic introspective observations. Galileo's and Darwin's observations and measurements can be reproduced by anyone in any culture having appropriate equipment. In the period after William James' challenge and before the behaviorists' 50+ year death grip on progress in psychology a number of groups pursuing an introspective approach could not agree on many basic observations (Wallace commented on, but did not really address this issue in the discussion period). The introspective and meditative approaches associated with many different cultures and religions don't seem remotely close to yielding a unified introspective description of consciousness and our mental processes that transcends their cultural origins in the way that astronomy and biology do.
Still, I think that the Buddha was the first great human biologist in his astute descriptions of levels of human behavior that corresponds roughly to stages in the biological evolution of our own brains and behavior (see my "Beast Within" essay). The mutual reinforcement of ancient introspective and modern scientific traditions yields some robustness, and perhaps the prospect of an eventual union of materialistic and mentalistic perspectives. Perhaps this will yield the "consciousness meter," analogous to a telescope or microscope, than we are now lacking.
The Aug. 14 science section of the NYTimes (PDF here) notes a technique which I mentioned in a previous post: making brain cells susceptible to light activation by inserting a light sensitive ion channel in their membranes.
A first step is establishing that it is possible to tweak a brain circuit by remote control and observe the corresponding behavioral changes in freely moving lab animals. On a recent Sunday at Stanford, Dr. Deisseroth and Feng Zhang, a graduate student, hovered over a dark brown mouse placed inside a white plastic tub. Through standard gene-manipulating tricks, the rodent had been engineered to produce channelrhodopsin only in one particular kind of neuron found throughout the brain, to no apparent ill effect....Mr. Zhang had implanted a tiny metal tube into the right side of the mouse’s partly shaved head...Now he carefully threaded a translucent fiber-optic cable not much wider than a thick human hair into that tube, positioned over the area of the cerebral cortex that controls movement...(then).. adjusted a key on a nearby laser controller box, and the fiber-optic cable glowed with blue light. The mouse started skittering in a left-hand spin, like a dog chasing its tail....“Turn it off, and then you can see him stand up,” Dr. Deisseroth continued. “And now turn it back on, and you can see it’s circling.”..Because the brain lacks pain receptors, the mouse felt no discomfort from the fiber optic, the scientists said, although it looked a tad confused. Scientists have long known that using electrodes to gently zap one side of a mouse’s motor cortex will make it turn the opposite way. What is new here is that for the first time, researchers can perturb specific neuron types using light.....Legend: Light stimulation every 200 milliseconds generates electrical activity, right, in an area of the brain associated with depression.
At Stanford, Dr. Deisseroth’s group has identified part of a brain circuit, in the hippocampus, that is underactive in rats, with some symptoms resembling depression. The neural circuit’s activity — and the animals’ — perked up after antidepressant treatment, in findings reported last week in the journal Science. Now the team is examining whether they can lift the rats’ low-energy behavior by using channelrhodopsin to rev up the sluggish neural zone...
The Stanford group has sent DNA copies of the “on” and “off” light-switch genes to more than 175 researchers eager to try them in all stripes of electrically excitable cells, from insulin-releasing pancreas cells to heart cells.
Tuesday, August 21, 2007
Thomas Insel writes a perspectives article in the Aug. 10 issue of Science (PDF here) on efforts to specify brain areas that show abnormal activity during depression. A clip from his article:
Neuroimaging studies of humans with major depressive disorder have largely pointed to prefrontal sites, especially implicating an area in the midline subgenual anterior cingulate cortex, often denoted as area 25 (see the figure. Not only does this region appear abnormal on structural and functional scans, but also it is enriched with the serotonin transporter, a target for many antidepressant drugs. Individuals inheriting a risk allele within the promoter of the serotonin transporter gene have reduced volume of area 25 and reduced functional coupling of this region to the amygdala, a subcortical region implicated in the regulation of emotion. An initial study of treatment-resistant depressed patients reports that deep brain stimulation adjacent to area 25 relieves the symptoms of major depressive disorder.
A fascinating bit of work by Kimchi and Dulac shows that female mice missing a gene involved in pheromone detection show the same sexual behaviour as males. Their abstract:
In mice, pheromone detection is mediated by the vomeronasal organ and the main olfactory epithelium. Male mice that are deficient for Trpc2, an ion channel specifically expressed in VNO neurons and essential for VNO sensory transduction, are impaired in sex discrimination and male–male aggression. We report here that Trpc2-/- female mice show a reduction in female-specific behaviour, including maternal aggression and lactating behaviour. Strikingly, mutant females display unique characteristics of male sexual and courtship behaviours such as mounting, pelvic thrust, solicitation, anogenital olfactory investigation, and emission of complex ultrasonic vocalizations towards male and female conspecific mice. The same behavioural phenotype is observed after VNO surgical removal in adult animals, and is not accompanied by disruption of the oestrous cycle and sex hormone levels. These findings suggest that VNO-mediated pheromone inputs act in wild-type females to repress male behaviour and activate female behaviours. Moreover, they imply that functional neuronal circuits underlying male-specific behaviours exist in the normal female mouse brain.There is some controversy over whether this result is unique to inbred laboratory mouse strains, so Dulac is now breeding wild mice with the Trpc2-mutant mice, to experiment with a 'wilder' version.
Monday, August 20, 2007
I enjoyed watching an interview of Tal Ben-Shahar on the John Stewart Daily News shows several days ago, discussing his new book "Happier." He has integrated threads of the positive psychology movement initiated largely by Martin Seligman (see my post on Seligman) to offer the most popular undergraduate course at Harvard. Although I usually have a gag reaction at most of the self-help stuff I see, I thought I would pass on some of the sane happiness tips from his website. And, a quick search at YouTube gets you his promotional video, also shown below.
* 1. Give yourself permission to be human. When we accept emotions — such as fear, sadness, or anxiety — as natural, we are more likely to overcome them. Rejecting our emotions, positive or negative, leads to frustration and unhappiness.
* 2. Happiness lies at the intersection between pleasure and meaning. Whether at work or at home, the goal is to engage in activities that are both personally significant and enjoyable. When this is not feasible, make sure you have happiness boosters, moments throughout the week that provide you with both pleasure and meaning.
* 3. Keep in mind that happiness is mostly dependent on our state of mind, not on our status or the state of our bank account. Barring extreme circumstances, our level of well being is determined by what we choose to focus on (the full or the empty part of the glass) and by our interpretation of external events. For example, do we view failure as catastrophic, or do we see it as a learning opportunity?
* 4. Simplify! We are, generally, too busy, trying to squeeze in more and more activities into less and less time. Quantity influences quality, and we compromise on our happiness by trying to do too much.
* 5. Remember the mind-body connection. What we do — or don't do — with our bodies influences our mind. Regular exercise, adequate sleep, and healthy eating habits lead to both physical and mental health.
* 6. Express gratitude, whenever possible. We too often take our lives for granted. Learn to appreciate and savor the wonderful things in life, from people to food, from nature to a smile.
Mery et al. show that a natural genetic polymorphism influences short versus long term memory in fruit flies. You can extract the basic message from their abstract, passing over the molecular details if that's not your gig:
Knowing which genes contribute to natural variation in learning and memory would help us understand how differences in these cognitive traits evolve among populations and species. We show that a natural polymorphism at the foraging (for) locus, which encodes a cGMP-dependent protein kinase (PKG), affects associative olfactory learning in Drosophila melanogaster. In an assay that tests the ability to associate an odor with mechanical shock, flies homozygous for one natural allelic variant of this gene (forR) showed better short-term but poorer long-term memory than flies homozygous for another natural allele (fors). The fors allele is characterized by reduced PKG activity. We showed that forR-like levels of both short-term learning and long-term memory can be induced in fors flies by selectively increasing the level of PKG in the mushroom bodies, which are centers of olfactory learning in the fly brain. Thus, the natural polymorphism at for may mediate an evolutionary tradeoff between short- and long-term memory. The respective strengths of learning performance of the two genotypes seem coadapted with their effects on foraging behavior: forR flies move more between food patches and so could particularly benefit from fast learning, whereas fors flies are more sedentary, which should favor good long-term memory.
Gina Kolata follows up here original article which I mentioned earlier, getting responses concerning means, medians, averages, etc.:
The Median, the Math and the Sex
By GINA KOLATA
David Gale, eminent emeritus mathematics professor at the University of California, Berkeley, member of the National Academy of Sciences, household name in certain rarefied circles, wanted to sound off about sex surveys. Over and over again, he said, they report results that logic dictates can’t be right. The total number of sex partners for men, he said, must equal the total number for women.
So when I said I’d write about that for The New York Times, he was delighted. Do you think I’ll get a response, he asked?
Little did he know. The moment the article hit The Times’s Web site last weekend, the e-mail messages flew and a discussion ensued that might be bewildering to the nonmathematician.
Gotcha, readers said: Data in one of the surveys cited, they said, reported the median numbers of sexual partners — and Dr. Gale’s argument, they said, only holds for the average number of partners.
Some were polite. Andrew Odlyzko, a mathematician at the University of Minnesota, wrote, “David Gale’s argument is unimpeachable” but there is this problem of medians.
Others were blunt: “Theorem: Professor Gale never went to prom. Proof: His High School Prom Theorem fatally assumes that everyone has a partner for every dance and no one ever sits out. The alternative is he has confused medians (at issue in the article) with means (averages, not middle-points in data), a rather elementary mistake for an emeritus professor of mathematics at Berkeley.”
The problem, Dr. Gale says, is that people leapt to conclusions. He had looked at the actual data from the survey citing medians and found that it could not possibly be correct. Of course he knew the difference between a median and a mean.
He wrote an explanation to send out to his numerous correspondents. But the e-mail messages kept coming.
A few correspondents, at least, were gracious. James Smith, an economist at the RAND Corporation, replied: “Yes, my point was only that of a nerd,” he wrote. “I have no doubt that the puzzle you pointed out is indeed true and cannot be explained away by medians and means.”
For the unconvinced, Dr. Gale’s response:
What I did was to get a copy of the C.D.C. report and use the data in its tables. The C.D.C. groups people into four groups and gives percentage of men and women in each group
From these figures you can estimate the total partners claimed by each sex. I got between 40 percent and 75 percent more male than female partners depending on how you guess the average on each interval. Thus, the raw data is inconsistent (so it doesn’t matter whether you take averages or medians or any other statistic).
I hope this clarifies.
Friday, August 17, 2007
Early in my professional career, I had a long discussion with Dan Koshland on a bus ride back from a scientific meeting. This conversation and our subsequent exchanges had a strong influence on me. Koshland was the editor of Science Magazine for many years, and we are all sad at his passing. Here is one of his perspectives articles from the magazine, on the nature of scientific discovery, titled "The Cha-Cha-Cha Theory of Scientific Discovery."
Scientific discoveries are the steps--some small, some big--on the staircase called progress, which has led to a better life for the citizens of the world. Each scientific discovery is made possible by the arrangement of neurons in the brain of one individual and as such is idiosyncratic. In looking back on centuries of scientific discoveries, however, a pattern emerges which suggests that they fall into three categories--Charge, Challenge, and Chance--that combine into a "Cha-Cha-Cha" Theory of Scientific Discovery. (Nonscientific discoveries can be categorized similarly.)
"Charge" discoveries solve problems that are quite obvious--cure heart disease, understand the movement of stars in the sky--but in which the way to solve the problem is not so clear. In these, the scientist is called on, as Nobel laureate Albert Szent-Györgyi put it, "to see what everyone else has seen and think what no one else has thought before." Thus, the movement of stars in the sky and the fall of an apple from a tree were apparent to everyone, but Isaac Newton came up with the concept of gravity to explain it all in one great theory.
"Challenge" discoveries are a response to an accumulation of facts or concepts that are unexplained by or incongruous with scientific theories of the time. The discoverer perceives that a new concept or a new theory is required to pull all the phenomena into one coherent whole. Sometimes the discoverer sees the anomalies and also provides the solution. Sometimes many people perceive the anomalies, but they wait for the discoverer to provide a new concept. Those individuals, whom we might call "uncoverers," contribute greatly to science, but it is the individual who proposes the idea explaining all of the anomalies who deserves to be called a discoverer.
"Chance" discoveries are those that are often called serendipitous and which Louis Pasteur felt favored "the prepared mind." In this category are the instances of a chance event that the ready mind recognizes as important and then explains to other scientists. This category not only would include Pasteur's discovery of optical activity (D and L isomers), but also W. C. Roentgen's x-rays and Roy Plunkett's Teflon. These scientists saw what no one else had seen or reported and were able to realize its importance.
There are well-known examples in each one of the Cha-Cha-Cha categories (see the figure). Two conclusions are immediately apparent. The first is that the original contribution of the discoverer can be applied at different points in the solution of a problem. In the Charge category, originality lies in the devising of a solution, not in the perception of the problem. In the Challenge category, the originality is in perceiving the anomalies and their importance and devising a new concept that explains them. In the Chance category, the original contribution is the perception of the importance of the accident and articulating the phenomenon on which it throws light.
Second, most important discoveries are usually not solved in one "Eureka" moment, as movie scripts sometimes suggest. True, there are moments in which a scientist has been mulling over various facts and problems and suddenly puts them all together, but most major discoveries require scientists to make not one but a number of original discoveries and to persist in pursuing them until a discovery is complete. Thus, to solidify his theory of gravity, Newton developed calculus and laws of physics that he described in his Principia. In a modern example, Michael Brown and Joseph Goldstein not only studied the metabolism of cholesterol but also discovered the role of lipoprotein receptors and the movement of key proteins from the outside to the interior of cells. Great discoveries are frequently covered in textbooks with a single word or phrase, but the concepts actually become solidified as scientific understanding by a series of discoveries.
It is also pertinent to define "the prepared mind" that is required for all of these innovations. Such a mind must be curious and knowledgeable. Curious refers to the fact that the individual is interested in phenomena and is constantly seeking to understand and explain them. Knowledgeable means that the individual has a background of facts and theories as a fertile incubator into which the new facts can fall.
The Cha-Cha-Cha Theory pertains to small everyday findings by scientists as well as the big discoveries that appear in history books. When, for example, a researcher discovers a new chemical isolated from a plant, there is so much understood today that the "charge" to that scientist is to find the formula and structure of the compound. There are now many ways to find the structure of an unknown chemical. Along the way there may be anomalous results that present challenges to the scientist and unexpected findings that must be interpreted by the prepared mind. So each of these represent real discoveries, not as big as a theory of gravity, but important just the same.
Finally, scientific discoveries are not that different from nonscientific discoveries. In the earliest days, there was an obvious "charge" for a set of rules to guide conduct in the close environment of a village that led to social customs and religious guidelines such as the Ten Commandments. As more complex societies emerged, the idea of a democratic vote probably resulted from a "charge" that saw the importance of getting consensus. The Magna Carta and the Bill of Rights came out of "challenges" to an entrenched social system. So when Einstein said that scientific thinking and general thinking were not that different, he probably meant that the patterns of thought of those with "prepared minds" in government and law operated by some of the same general principles as science, even though the methods of science and law are very different.
Someday we may understand the arrangement of neurons in the brain enough to understand how originality can arise. A wild guess would be that the brain of a discoverer has a greater tendency than the average individual to relate facts from highly separate compartments of the brain to each other. As a step to making that Herculean problem tractable, we can at least follow the traditions of scientific reductionism and use the Charge, Challenge, and Chance categories to make the interpretation of brain imaging experiments easier to analyze.
The fact that monkeys prefer silence suggests that humans' music responses may reflect evolutionary selection for cognitive processes linked to emotion and motivation. Here is the brief review from the Random Samples section of the Aug. 3 issue of Science:
Cognitive scientists Joshua McDermott of the Massachusetts Institute of Technology in Cambridge and Marc Hauser of Harvard University put tamarins and marmosets in an apparatus with two chambers, each rigged to play music whenever an animal entered. In one experiment, the musical choices were a flute lullaby (65.26 beats per minute) and Alec Empire's electronic techno hit "Nobody Gets Out Alive" (369.23 beats per minute). The monkeys spent an average of about two-thirds of their time on the lullaby side, showing that they prefer slower tempos. But when given the choice of silence, lullabies, or a Mozart concerto, they spent most of their time avoiding music altogether. A similar experiment with eight humans showed a distinct preference for music--especially lullabies--over silence, the authors report in the September issue of Cognition.
"The observations suggest that only humans have a natural, or innate, inclination to engage with music," says Isabelle Peretz of the University of Montreal in Canada, who has concluded from studies of people with amusia (tone deafness) that humans have special brain pathways for music (Science, 1 June 2001, p. 1636). McDermott and Hauser--who earlier found that monkeys have no preference between harmonious and dissonant music--suggest that humans' music responses may reflect a "unique evolutionary history of selection" for cognitive processes linked to emotion and motivation.
Thursday, August 16, 2007
From the Eprint archive of the Assoc. for the Scientific Study of Consciousness:
1. Windt, Jennifer Michelle and Metzinger, Thomas (2006) The philosophy of
dreaming and self-consciousness: What happens to the experiential subject
during the dream state? In: The new science of dreaming (1505 downloads from
18 countries). http://eprints.assc.caltech.edu/200/
2. Rosen, Alan and Rosen, David B. (2006) The Design of a
Sensation-generating Mechanism in the Brain: A first step towards a
quantitative definition of consciousness. In: Consciousness and Cognition
(1030 downloads from 20 countries). http://eprints.assc.caltech.edu/195/
3. Sagiv, Noam and Ward, Jamie (2006) Crossmodal interactions: lessons from
synesthesia. In: Visual Perception, Part 2 (873 downloads from 17
4. Koriat, A. (2006) Metacognition and Consciousness. In: Cambridge handbook
of consciousness. CUP (801 downloads from 17 countries).
5. Robbins, Stephen E (2006) Bergson and the holographic theory of mind.
Phenomenology and the Cognitive Sciences, 5. pp. 365-394 (762 downloads from
14 countries). http://eprints.assc.caltech.edu/206
Notice that many of this year's conference presentations and related
material can now be found in the archive - for example, this year's William
James Prize winner Sid Kouder's paper: Kouider, Sid and Dehaene, Stanislas
and Jobert, Antoinette and Le Bihan, Denis (2007) Cerebral Bases of
Subliminal and Supraliminal Priming during Reading. Cerebral Cortex, 17 (9).
pp. 2019-2029. ( http://eprints.assc.caltech.edu/321)
Posted by Deric Bownds at 6:40 AM
From Lenoir et al.:
Background: Refined sugars (e.g., sucrose, fructose) were absent in the diet of most people until very recently in human history. Today overconsumption of diets rich in sugars contributes together with other factors to drive the current obesity epidemic. Overconsumption of sugar-dense foods or beverages is initially motivated by the pleasure of sweet taste and is often compared to drug addiction. Though there are many biological commonalities between sweetened diets and drugs of abuse, the addictive potential of the former relative to the latter is currently unknown.Thus, they demonstrate (at least in rats) that:
Principal finding: ...when rats were allowed to choose mutually-exclusively between water sweetened with saccharin–an intense calorie-free sweetener–and intravenous cocaine–a highly addictive and harmful substance–the large majority of animals (94%) preferred the sweet taste of saccharin. The preference for saccharin was not attributable to its unnatural ability to induce sweetness without calories because the same preference was also observed with sucrose, a natural sugar. Finally, the preference for saccharin was not surmountable by increasing doses of cocaine and was observed despite either cocaine intoxication, sensitization or intake escalation–the latter being a hallmark of drug addiction.
...intense sweetness can surpass cocaine reward, even in drug-sensitized and -addicted individuals.And speculate:
...that the addictive potential of intense sweetness results from an inborn hypersensitivity to sweet tastants. In most mammals, including rats and humans, sweet receptors evolved in ancestral environments poor in sugars and are thus not adapted to high concentrations of sweet tastants. The supranormal stimulation of these receptors by sugar-rich diets, such as those now widely available in modern societies, would generate a supranormal reward signal in the brain, with the potential to override self-control mechanisms and thus to lead to addiction.
Wednesday, August 15, 2007
I came across a reaction to my original posting on this topic which is worth some discussion, because I think it oversimplifies the views of 'reductionists.' The original posting (which has received more views than any other posting on this blog) began with this brief introduction to some quotes from an article on the Neuro-philosophers Paul and Patricia Churchland:
I rarely mention my internal experience and sensations on this blog - first, because I have viewed readers as "wanting the beef," objective stuff on how minds work. Second and more important, because my experience of noting the flow of my brain products as emotion laced chunks of sensing/cognition/action - knowing the names of the neurotransmitters and hormones acting during desire, arousal, calming, or affiliation - strikes me as a process which would feel quite alien to most people. Still, if we are materialists who believe that someday we will understand how the brain-body generates our consciousness and sense of a self, we will be able to think in terms like the following (a quote taken from Larissa MacFarquhar's profile of Paul and Patricia Churchland in the Feb. 12 New Yorker Magazine):to which one comment was:
Alien, yes. But it is also largely devoid of meaningful self-exploration as well. Science at it's worst takes itself too seriously. New discoveries are considered automatically as an advance in understanding. A dialogue about the known facts of internal experience contains about as much meaning in moment to moment experience as reciting the letters in a bowl of alphabet soup!This is surprising to hear from a professional psychologist. It is not meaningful to simply be able to note whether one is angry, sad, loving, or is the grip of an obsession (or image brain correlates of those processes)? - which is what I am saying with "noting the flow of my brain products as emotion laced chunks of sensing/cognition/action." Consider an obsessive compulsive disorder such as constantly washing one's hands. Cognitive therapy training to 'notice a part of me that is not working' and not follow its direction has been useful for some in treatments of this syndrome. The technique of mindfulness meditation which simply notes thoughts and emotions as they arise can have the practical consequence of permitting more choice in whether they are expressed in actions.
A further comment was:
The so-called "objective" human sciences reduces people to parts and pieces so small that we can't recognize commonality or identify our own experiences within the narrow concepts in the models espoused. Science has somehow become primarily inductive. The deep understanding of theoretical deduction seems to have fallen into disfavor. Could it be because it is so easy to pick apart the substance of theoretical systems? I suspect so. The more reductionistic the model, the less likely it can be criticized.I don't think that 'reductionists' like myself or the Churchlands think that focusing on different specific parts and mechanisms gets a complete description of the 'whole.' We don't deny the relevance of phenomenology of the whole system, of emergent properties, holism, etc. We simply think that it helps to know something about the parts!
The relevant arguments are quite venerable. In the ancient Buddhist text "The Question of King Milinda" the Greek King Menander (Milinda), an heir to Alexander the Great and military commander of what is now Afghanistan, questioned the local Buddhist sage. The sage asked the king to "explain to me what a chariot is.... Is the axle the chariot? Are the wheels, or the frame, or the yoke, or the reins the chariot? If not, then is the chariot all these parts?, is the chariot anything else than these?" (I take this rendering from Mark Epstein's book "Going on Being.")
The point is that 'chariot' (like 'awareness' or 'consciousness') is obviously more than a mere word, but it exists only in relationship to its parts. It doesn't help a lot to get snarled up in debates about induction versus deduction.
Posted by Deric Bownds at 6:40 AM
A mini-review (PDF here) is offered by Knutson and Bossaerts on neural antecedents of financial decisions. It is one of a series of in the August 1 issue of the Journal of Neuroscience devoted to the neural basis of choice and decision making. Their abstract:
To explain investing decisions, financial theorists invoke two opposing metrics: expected reward and risk. Recent advances in the spatial and temporal resolution of brain imaging techniques enable investigators to visualize changes in neural activation before financial decisions. Research using these methods indicates that although the ventral striatum plays a role in representation of expected reward, the insula may play a more prominent role in the representation of expected risk. Accumulating evidence also suggests that antecedent neural activation in these regions can be used to predict upcoming financial decisions. These findings have implications for predicting choices and for building a physiologically constrained theory of decision-making.An overview (The Neural Basis of Choice and Decision Making) of the other mini-reviews in this series is given in an introduction by Balleine, which I reproduce here:
Decision making refers to the ability of humans and other animals to choose between competing courses of action based on the relative value of their consequences. This capacity is, therefore, fundamentally integrative, melding the complex cognitive processes through which causal relations between actions and consequences are encoded, retrieved, and maintained in working memory with the motivational processes that determine the value, or utility, of actions or sequences of actions. As readers of this journal will be well aware, research in decision making has expanded in a variety of directions in recent years, but most notably into neuroscience. There are many reasons for this development, some merely technical, such as the increased use of functional magnetic resonance imaging (fMRI) in humans, but others that are more obviously innovative and that mark a change in the dominant approach to investigating the neural bases of the complex capacities of animals. There appears to be a developing consensus that the long tradition of studying these capacities by examining analogous processes in simple model systems has become an old tradition; that, rather than using a simple neural or behavioral preparation, methodologies better suited to examining functional, as opposed to structural, problems will provide a more secure basis for rapid progress. Indeed, much of the success of recent research in decision making has come from recognizing that the interaction of the cognitive, motivational, and behavioral processes engaged during the course of specific decisions cannot be reified to a single specialized circuit, cell type, or intracellular process and are best understood at a systems level.
As a consequence, the neuroscience of decision making is a very broad enterprise and crosses many traditional boundaries between research disciplines, species, and brain regions. This breadth is immediately apparent from a cursory survey of the range of interests of the authors of the following Mini-Reviews. There are, however, clear areas of overlap, and these have been exploited to explore what we see as emerging themes in decision-making research. In this series, these include descriptions of studies integrating computational and neuroeconomic approaches to investigate subjective decision variables, financial decisions, and the executive and evaluative functions of prefrontal cortex [particularly the role of orbitofrontal cortex (OFC) in establishing a common currency of value], together with reviews of recent research examining the functions of discrete corticostriatal networks and their integrated dopaminergic afferents in the acquisition and control of goal-directed and habitual instrumental actions.
Although the individual papers review themes that are, themselves, complex areas of issue around which substantial research efforts are currently organizing, they are each presented within a larger context and so, together, provide a general overview of this developing area. For example, in their description of the application of computational approaches to decision making, Doya and Corrado (2007) review both the development of computational models capable of capturing the dynamics of individual choice and specific cases in which the internal variables of these models have provided the basis for extracting the correlates of subjective choice from the electrophysiological data of primates. In this case, it is the dynamic integration of the computational, neural, and behavioral data that has provided insight into the subjective variables controlling choice. Similarly, Knutson and Bossaerts (2007) describe the emerging neurofinance approach to decision making but also examine the specific application of models of decision making under risk and the behavioral tasks that have been developed to examine financial decision processes in human subjects together with their neural correlates using fMRI.
Lee et al. (2007) review research on the involvement of prefrontal cortex in decision making in primates and, in the light of the connectivity of subdivisions of this region and of formal theories of decision making, propose that the lateral, medial, and ventral subregions may have the more specialized task of deriving predictions regarding the future value of reward on the basis of states, actions, and local predictive cues, respectively. Interestingly, Murray et al. (2007) come to similar conclusions with regard to the role of OFC in decision making based on a review of the comparative literature. They point particularly to its role in deriving reward value from predictive cues as well as to evidence suggesting that the OFC may play a specialized role by allowing animals to compare values across distinct event categories.
Finally, it is interesting to note convergence in the proposed functions of corticostriatal circuits and their midbrain dopaminergic afferents in decision making that has emerged in recent research. Although the involvement of the basal ganglia in motor learning, particularly in sensorimotor association, has long been recognized, recent evidence, reviewed by Balleine et al. (2007), suggests that they also play a critical role in the acquisition of actions instrumental to gaining access to reward (i.e., in goal-directed actions). Importantly, studies using rodent, nonhuman primate, and human subjects have found evidence of heterogeneity of neural function not previously anticipated, particularly in the striatum. Furthermore, there is evidence of a corresponding heterogeneity in neurodegenerative disorders, in neuronal plasticity, and in the involvement of dopaminergic processes across striatal subregions. The suggestion that the burst-firing pattern of midbrain dopamine neurons serves as an error signal for the prediction of reward has generated close collaboration between researchers using computational and neurophysiological approaches to study dopamine function. More recently, alterations in dopamine signaling have been reported to lead to regional changes in plasticity in the corticostriatal pathway together with changes in the excitability of the striatal output neurons. Indeed, as reviewed by Wickens et al. (2007), rapid alterations in dopamine transmission are related to substantial changes in the coordinated activity of neuronal ensembles in discrete corticostriatal circuits in a manner that could lead to the emergence of distinct patterns of behavioral abnormality. Clearly, the involvement of dopamine in striatal function, and in decision making generally, is rich and varied and is something that we are only beginning to understand.
Tuesday, August 14, 2007
Daphne and I are working up the 3rd Beethoven Violin - Piano sonata, and made this video at my Twin Valley home to help us note dynamic problems and fumbled passages more clearly.
It has been commonly assumed that technology and institutional changes were much more important than changes in basic human nature in triggering the sudden escape from subsistence poverty towards personal wealth and production that occurred at the end of the 18th century. The Aug. 7 issue of the NYTimes has a review of the work of Gregory Clark, who argues that the Industrial Revolution occurred because of a change in the nature of the human population. Through analysis of ancient wills, Clark found that:
Generation after generation, the rich had more surviving children than the poor... there must have been constant downward social mobility as the poor failed to reproduce themselves and the progeny of the rich took over their occupations...The modern population of the English is largely descended from the economic upper classes of the Middle Ages...As the progeny of the rich pervaded all levels of society...the behaviors that made for wealth could have spread with them...several aspects of what might now be called middle-class values changed significantly from the days of hunter gatherer societies to 1800. Work hours increased, literacy and numeracy rose, and the level of interpersonal violence dropped....Another significant change in behavior, Dr. Clark argues, was an increase in people’s preference for saving over instant consumption, which he sees reflected in the steady decline in interest rates from 1200 to 1800.I knew I had read, and written, about this sort of idea. After thrashing about looking for it, I was embarrassed to simply find it in my Biology of Mind book, in the chapter on Hominid Mind:
Students of animal behavior use the term "phenotypic cloning" to describe the process by which parents can so firmly impress behaviors on their offspring that the behaviors (phenotypes) seem to be inherited. (In spite of what we like to think, we all act remarkably like our parents as we grow older.) A core point is the argument that differences in behavioral styles between one family line and another provide a context for natural selection. The behaviors that work best are passed on because of differential reproductive success, and less adaptive behaviors are lost from the "phenotypic pool" analogous to the gene pool of genetics. This mechanism acts also at the level of cultures of humans and animals, and in this context it is termed group selection. Over longer periods of time, genetic changes in individuals that facilitate the adaptive behaviors adopted by a group might then be selected for. This is the Baldwin effect mentioned in the section "Co-evolution of Humans and Their Tools" and is a scenario offered by some evolutionary psychologists.A main point of this post is to pass on the elegant graphic in the NYTimes article, which summarizes Clark's ideas:
Monday, August 13, 2007
Perhaps the most common evidence offered in support of males and females having evolved different sexual psychologies is from numerous surveys that show, across cultures, that men report having many more sexual partners than women. This is argued to reflect a basic underlying genetic fact: the best investment for a male to generate the maximum number of offspring with his genes is to impregnate as many females as possible. A woman has to invest much more in her offspring and is better served by selected fewer male partners who are more likely to provide support for her and her children.
Gina Kolata, in the Aug. 12 N.Y. Times, reports an interesting slant on this story. Simple math shows that the numbers don't add up... she quotes David Gale of U.C. Berkeley:
Surveys and studies to the contrary notwithstanding, the conclusion that men have substantially more sex partners than women is not and cannot be true for purely logical reasons...By way of dramatization, we change the context slightly and will prove what will be called the High School Prom Theorem. We suppose that on the day after the prom, each girl is asked to give the number of boys she danced with. These numbers are then added up giving a number G. The same information is then obtained from the boys, giving a number B...Theorem: G=B...Proof: Both G and B are equal to C, the number of couples who danced together at the prom. Q.E.D.Sex researchers know that this is correct. Men and women in a population must have roughly equal number of partners. So why do men report many more than women? They exaggerate? They go to prostitutes who don't appear in the survey? (The latter would not explain the huge difference in reporting.) The most likely explanation:
...the survey data themselves may be part of the problem. If asked, a man, believing that he should have a lot of partners, may feel compelled to exaggerate, and a woman, believing that she should have few partners, may minimize her past...In this way the false conclusions people draw from these surveys may have a sort of self-fulfilling prophecy.
I'm a cat person, so was attracted to this crazy story in the July 26 issue of the New England Journal of Medicine: "A day in the life of Oscar the cat." It describes the cat's daily rounds in a New England rest home.
Since he was adopted by staff members as a kitten, Oscar the Cat has had an uncanny ability to predict when residents are about to die. Thus far, he has presided over the deaths of more than 25 residents on the third floor of Steere House Nursing and Rehabilitation Center in Providence, Rhode Island. His mere presence at the bedside is viewed by physicians and nursing home staff as an almost absolute indicator of impending death, allowing staff members to adequately notify families. Oscar has also provided companionship to those who would otherwise have died alone. For his work, he is highly regarded by the physicians and staff at Steere House and by the families of the residents whom he serves.
The Dana Press (see www.dana.org) has published a volume of articles on mind and brain from The Scientific American, edited by Floyd Bloom (check out the table of contents on the Dana website). It contains a number of interesting articles that I am surprised that I missed at the time. (By the way, the Dana website is a good source of information on recent research on mind and brain, and has special sections devoted to kids and to seniors.)
Friday, August 10, 2007
Yan et al. have shown that getting rid of a protein involved in adrenaline's control of heart rate reduces heart rate increase during stress and allows mice to live longer and have healthier hearts. Here is their abstract:
Mammalian models of longevity are related primarily to caloric restriction and alterations in metabolism. We examined mice in which type 5 adenylyl cyclase (AC5) is knocked out (AC5 KO) and which are resistant to cardiac stress and have increased median lifespan of ∼30%. AC5 KO mice are protected from reduced bone density and susceptibility to fractures of aging. Old AC5 KO mice are also protected from aging-induced cardiomyopathy, e.g., hypertrophy, apoptosis, fibrosis, and reduced cardiac function. Using a proteomic-based approach, we demonstrate a significant activation of the Raf/MEK/ERK signaling pathway and upregulation of cell protective molecules, including superoxide dismutase. Fibroblasts isolated from AC5 KO mice exhibited ERK-dependent resistance to oxidative stress. These results suggest that AC is a fundamentally important mechanism regulating lifespan and stress resistance.
A bit outside our normal subject area, but a visually amazing compendium and demonstration of how publicly available geographic and atmospheric data can be organized and presented...It made me a bit queasy to zoom from the whole earth view to my Twin Valley home in Middleton Wisconsin.
Thursday, August 09, 2007
Damage to parts of the visual cortex can cause blindsight or agnosia, in which conscious awareness of an object is absent but subject can still make accurate judgements about it. Binsted et al al offer an interesting demonstration that this phenomenon is is part of the normal functioning of the visual system. They used the masking paradigm shown in the figure below to abolish conscious perception of an object, and found that subjects could point to that object as easily as to one that was perceived. Here is their abstract, followed by the central figure.
After lesions to primary visual cortex, patients lack conscious awareness of visual stimuli. Interestingly, however, some retain the ability to make accurate judgments about the visual world (i.e., so-called blindsight). Similarly, damage to inferior occipitotemporal regions of cortex (e.g., lateral occipital cortex) can result in an inability to perceive object properties while retaining the ability to act on them (i.e., visual form agnosia). In the present work, we demonstrate that the ability to interact with objects in the absence of conscious awareness is not isolated to those with restricted neuropathologic conditions. Specifically, neurologically intact individuals are able to program and execute goal-directed reaching movements to a target object without awareness of extrinsic target properties; they accurately tune the dynamics of their movement and modulate it online without conscious access to features of the goal object. Thus, the planning and execution of actions are not dependent on conscious awareness of the environment, suggesting that the phenomenon of blindsight (and agnosia) reflect normal conditions of the visual system.
Fig. 1. Display sequence for experiment. Participants initially observed a fixation cross and home position. After a variable foreperiod (1–3 s), an array of circles appeared; one circle was identified as the target by 4 red cue circles. In all cases the participant was asked to point to the middle of the target as quickly and accurately as possible. (a) Unconscious condition. The red cue circles remained present after removal of the array. This results in object substitution masking (4, 14), where participants have no conscious access to target properties (e.g., size). (b) Conscious condition. The red cue circles were removed concurrently with the array. In this condition, participants could consciously report the target properties.
These evolutionary psychology entrepreneurs know how to get their press: John Tierney describes a study from David Buss and collaborators asking 2,000 people why they'd had sex. You can see some of the answers, which includes "to get rid of a headache," here.
Wednesday, August 08, 2007
Carl Zimmer writes an interesting profile of the work and ideas of Marin Nowak at Harvard in the July 31 NY Times Science section (PDF here). Here are some edited clips:
Nowak argues that cooperation is one of the three basic principles of evolution. The other two are mutation and selection. On their own, mutation and selection can transform a species, giving rise to new traits like limbs and eyes. But cooperation is essential for life to evolve to a new level of organization. Single-celled protozoa had to cooperate to give rise to the first multicellular animals. Humans had to cooperate for complex societies to emerge.The article describes Nowak's work with models that are intellectual descendants of the Prisoner's Dilemma puzzle.
These models incorporate neighborhoods of players in which tight clusters of cooperators emerge, and defectors elsewhere in the network are not able to undermine their altruism. The emergence of cooperation is described with a simple equation: B/C>K. That is, cooperation will emerge if the benefit-to-cost (B/C) ratio of cooperation is greater than the average number of neighbors (K)...Nowak and his colleagues also pioneered a version of the Prisoner’s Dilemma in which players acquire reputations. They found that if reputations spread quickly enough, they could increase the chances of cooperation taking hold. Players were less likely to be fooled by defectors and more likely to benefit from cooperation.
When reputation is at stake, animals as well as humans switch from selfish to altruistic behavior, because only the latter is socially rewarded (1, 2). But how do they assess whether their actions are observed? Recent investigations into human behavior have shown that subtle cues of being watched such as two stylized eye-like shapes on a computer screen background suffice to change behavior (3). A picture showing a pair of eyes attached to a cafeteria collection box significantly raises the donated amount compared to a flower symbol; in fact, the eyes were most effective when looking directly at the observer (4).
Although just ink on paper, these eye-shaped cues seem to elicit unconscious hard-wired reactions. Indeed, electrophysiological responses recorded from the scalp of normal subjects showed responses to isolated eyes that are even larger than the responses to full faces (5). Brain imaging studies in humans have also highlighted a role for the superior temporal sulcus (STS) and amygdala in gaze processing; the STS is likely to be essential for recognizing the eyes, head, and body as stimuli used in social communication, whereas the amygdala is likely to be essential for attaching social and emotional significance to these stimuli (6). Interestingly, even birds respond strongly to eye-like shapes, especially when two eyes are staring at them (7).
What is the benefit of watching someone? Spying on others seems widespread in animals and humans (8). By snooping on one another's social life, animals and humans can work out how to behave when they meet in the future. Recent experiments showed that even fish gain sophisticated information from watching members of the same species (9). Some fish can infer the social rank of others by observation alone and use this information to their own advantage in future encounters (10). So it comes as no surprise that both humans and animals try to deceive observers by behaving as they want to be seen by others to secure future gains.
For example, the cleaning wrasse fish grooms its client fish in the friendliest way when other clients watch, but without an audience it prefers to bite off pieces of its client's skin (11). In a dictator game experiment, only one player (the dictator) is endowed with money and may share it with a second player. Although unidentifiable human "dictators" share almost nothing (12), face-to-face identification increases the share rate to 50% (13). Consequently, in order to gain accurate information, observers should avoid being recognized: Indeed, some social birds have eyes concealed in dark areas or stripes, ensuring that the observed individual cannot detect being the target (14).
This is where humans differ from most animals. We have large white sclera on either side of the dark central iris when looking directly at the observer. This seems to be an honest signal of where we watch (6). Obviously there has been a net selective advantage of signaling the direction of our gaze in social interactions. However, having such eyes should be disadvantageous when trying to observe others' "unobserved" behavior, because we should take into account that the observed person turns altruistic as soon as our observing gaze is recognized.
Can we escape being watched? Whenever a person can be recognized by any cue, bad conduct may incur costs. Instead of behaving altruistically, people sometimes avoid having to justify their behavior by masking their faces, for example, at a masked ball, when robbing a bank, etc. Interestingly, the usual way to remove the identity of people on photos is to cover their eyes by a black stripe. Visual cues of faces seem to be of prime importance. Thus, either masking such cues or paying attention to being watched may be socially selected.
Are you being naughty or nice? Totem poles put up in villages in North America several hundred years ago standing vigilant at attention, with ever-watchful eyes. Unlike natural goats, the stylized goat has "human eyes" with white sclera stressing the direction of his gaze. (CREDIT: TONY J. PITCHER/UNIVERSITY OF BRITISH COLUMBIA)
Thus, a new dimension arises when issues of reputation are present in human social dilemmas. An "arms race" of hiding signals between observers and observed may result: Observer Alice should take into account that the behavior of Bob (the observed) changes and therefore should conceal her watching; Bob should be very alert to faint signals of being watched by Alice, but he should avoid any sign of having recognized Alice's watching when switching from selfish to altruistic behavior. He should avoid turning his gaze in the direction of the recognized observer. On the other hand, as soon as Alice sees that Bob has recognized that he is being observed, she should eventually not reward the observed altruistic behavior.
An arms race between observing and being observed has implications for the large body of recent research on human altruism. Observed altruistic behavior may often be less the expression of a personal trait than an optimal response to the faint feeling of being observed. Would altruism then function as a potential deceit? For example, what we expect for the efficient interaction between reputation and costly punishment in social dilemmas--where individual and social interests are at odds--might depend on the recognized state of the signaling arms race (15). When cues revealing that the observed person has discovered the observation are indeed so subtle that altruism is a successful deceit, the positive effects of reputation can be expected to be present to a much greater extent. However, when the observer can conceal his spying, reputation is subjectively not at stake and thus will not induce altruism.
Does the observer thus really want to see "unobserved" behavior? Yes, but only if the social partner interacts with the observer mostly anonymously and she profits from seeing his "normal" behavior and reacts accordingly. Otherwise she should try her best to generate the impression that her social partners always feel observed so that their "normal" behavior is altruistic. Perhaps this is achieved in some societies by the ever-present watchful eyes of totem poles (see the figure) or a god that "sees through everything." Even actors on billboards, a modern form of ink on paper, may elicit unconscious social reactions in our amygdala and thus influence our behavior.
Tuesday, August 07, 2007
Bainbridge offers a review in the 27 July issue of Science (PDF here) on the scientific research potential of virtual worlds. I wonder if this kind of work would face the same criticism as studies of animal behavior in zoos rather than in the wild (a issue revisited in my recent posting on the bonobo ape). Here is the abstract:
Online virtual worlds, electronic environments where people can work and interact in a somewhat realistic manner, have great potential as sites for research in the social, behavioral, and economic sciences, as well as in human-centered computer science. This article uses Second Life and World of Warcraft as two very different examples of current virtual worlds that foreshadow future developments, introducing a number of research methodologies that scientists are now exploring, including formal experimentation, observational ethnography, and quantitative analysis of economic markets or social networks.From his conclusion, "Human Challenges"
Figure: Three avatars in SL making a door. In a virtual design studio, two scientists are admiring the work of a student intern (center) who is creating a set of displays demonstrating human-centered computing. After the combination lock has been set and made smaller, the door can readily be moved to its final location. Similar methods can be used to construct laboratory facilities and experimental equipment.
Many virtual worlds may foster scientific habits of mind better than traditional schools can, because they constantly require inhabitants to experiment with unfamiliar alternatives, rationally calculate probable outcomes, and develop complex theoretical structures to understand their environment (60–62). Probably for better, but conceivably for worse, virtual worlds are creating a very new context in which young people are socialized to group norms, learn intellectual skills, and express their individuality (63). The "graduates" of SL and WoW may include many future engineers, natural scientists, and social scientists ready to remake the real world in the image of the virtual worlds.