An anatomical signature for literacy

Here is some fascinating work from Carreiras et al. showing brain changes in adult Colombian guerrillas re-integrating into mainstream society and learning to read for the first time as adults:

Language is a uniquely human ability that evolved at some point in the roughly 6,000,000 years since human and chimpanzee lines diverged. Even in the most linguistically impoverished environments, children naturally develop sophisticated language systems. In contrast, reading is a learnt skill that does not develop without intensive tuition and practice. Learning to read is likely to involve ontogenic structural brain changes, but these are nearly impossible to isolate in children owing to concurrent biological, environmental and social maturational changes. In Colombia, guerrillas are re-integrating into mainstream society and learning to read for the first time as adults. This presents a unique opportunity to investigate how literacy changes the brain, without the maturational complications present in children. Here we compare structural brain scans from those who learnt to read as adults (late-literates) with those from a carefully matched set of illiterates. Late-literates had more white matter in the splenium of the corpus callosum and more grey matter in bilateral angular, dorsal occipital, middle temporal, left supramarginal and superior temporal gyri. The importance of these brain regions for skilled reading was investigated in early literates, who learnt to read as children. We found anatomical connections linking the left and right angular and dorsal occipital gyri through the area of the corpus callosum where white matter was higher in late-literates than in illiterates; that reading, relative to object naming, increased the interhemispheric functional connectivity between the left and right angular gyri; and that activation in the left angular gyrus exerts top-down modulation on information flow from the left dorsal occipital gyrus to the left supramarginal gyrus. These findings demonstrate how the regions identified in late-literates interact during reading, relative to object naming, in early literates.

A little fellatio goes a long way...

I can't resist passing on this item in ScienceNow:

Oral sex is surprisingly rare in the animal kingdom. Humans do it, of course. As do bonobos, our close relatives. But now researchers have observed the practice for the first time in a non-primate. Libiao Zhang, a biologist at Guangdong Entomological Institute in Guangzhou, China, and colleagues had been studying the mating behavior of the short-nosed fruit bat (Cynopterus sphinx), which is native to southeast Asia....Of the 20 observed mating bat pairs, 70% of the females performed fellatio on the males, the team reports online this week in PLoS ONE. The males never withdrew while being licked, and the authors found that the longer a female licked, the longer copulation lasted (for each second of licking, the female bats gained 6 seconds of copulation). The team speculates that licking helps maintain the male's erection, and that the saliva increases lubrication, both of which may prolong intercourse. In all, fellating females mated for an average of 4 minutes, twice as long as the other females.

Manipulating sex differences in romantic selectivity

From Finkel and Eastwick:

Men tend to be less selective than women when evaluating and pursuing potential romantic partners. The present experiment employed speed-dating procedures to test a novel explanation for this sex difference: The mere act of physically approaching a potential romantic partner (vs. being approached), a behavior that is more characteristic of men than of women, increases one's attraction to that partner. This hypothesis was supported in a sample of speed daters (N= 350) who attended a heterosexual event where either men (eight events) or women (seven events) rotated from one partner to the next while members of the other sex remained seated. Rotators were significantly less selective than were sitters, which meant that the tendency for men to be less selective than women at events where men rotated disappeared at events where women rotated. These effects were mediated by increased self-confidence among rotators relative to sitters.

Denialism

Janet Maslin offers a review of an interesting new book by Michael Specter: DENIALISM -How Irrational Thinking Hinders Scientific Progress, Harms the Planet and Threatens Our Lives. He explores the ways in which scientific information is misunderstood by a sizeable portion of the populace, struggling with change, that deflects reality to bask in more comfortable illusion. Here are a few clips:

In “The Organic Fetish,” a chapter that ably illustrates this book’s tactics and purpose, he uses Whole Foods as the apotheosis of a strain of magical thinking. First of all, he asks, what exactly is organic food? Is it more healthful than genetically engineered food or than food that has been harvested by robot-guided machinery rather than human hands? And are organic fertilizers more earth-friendly than synthetic ones? “There are no short answers to those questions (at least none that are true),” he says...And whatever the merits of organic farming for societies that can afford it, what happens in places where food, land or water are scarce? There is a case to be made for agricultural methods that make the most efficient use of new technologies, and thus for genetically engineered crops that produce increased yields. But these are widely derided as Frankenfoods. Their ability to scare people and trigger blanket resistance is one of this book’s foremost illustrations of denialism in action.

Of all the grenades lobbed by “Denialism,” the most explosive is aimed at Dr. Weil, the otherwise-sacrosanct avatar of New Age medicine. In the chapter called “The Era of Echinacea” Mr. Specter describes signing up for one of Dr. Weil’s customized mail-order regimens. “Dr. Weil, who argues that we need to reject the prevailing impersonal approach, reached out from cyberspace to recommend each of these pills wholeheartedly and specifically, just for me,” But Mr. Specter decided that the pills advocated by Dr. Weil fell into three categories: those that did no particular good, those that did some good but could interfere with the effects of prescribed medicines, and those that “seemed just plain dangerous.”..What bothered him more than Dr. Weil’s advice was Dr. Weil’s philosophy. “The idea that accruing data is simply one way to think about science has become a governing tenet of the alternative belief system,” Mr. Specter writes. And the additional idea that the evidence of experience is as important as the results of meticulous scientific testing is, in Mr. Specter’s view, one of the most dangerous forms of denialism, especially when it comes from a figure of Dr. Weil’s stature. As “Denialism” puts it: “It is much easier to dismiss a complete kook — there are thousands to choose from — than a respected physician who, interspersed with disquisitions about life forces and energy fields, occasionally has something useful to say.”

Neural correlates of musical consonance and dissonance

Bidelman and Krishnan make interesting observations suggesting that very fundamental low level sensory processing at the level of the brain stem may determine what sound intervals we find consonant or dissonant:

Consonant and dissonant pitch relationships in music provide the foundation of melody and harmony, the building blocks of Western tonal music. We hypothesized that phase-locked neural activity within the brainstem may preserve information relevant to these important perceptual attributes of music. To this end, we measured brainstem frequency-following responses (FFRs) from nonmusicians in response to the dichotic presentation of nine musical intervals that varied in their degree of consonance and dissonance. Neural pitch salience was computed for each response using temporally based autocorrelation and harmonic pitch sieve analyses. Brainstem responses to consonant intervals were more robust and yielded stronger pitch salience than those to dissonant intervals. In addition, the ordering of neural pitch salience across musical intervals followed the hierarchical arrangement of pitch stipulated by Western music theory. Finally, pitch salience derived from neural data showed high correspondence with behavioral consonance judgments (r = 0.81). These results suggest that brainstem neural mechanisms mediating pitch processing show preferential encoding of consonant musical relationships and, furthermore, preserve the hierarchical pitch relationships found in music, even for individuals without formal musical training. We infer that the basic pitch relationships governing music may be rooted in low-level sensory processing and that an encoding scheme that favors consonant pitch relationships may be one reason why such intervals are preferred behaviorally.

Can you believe...? The perfect product

Starting to read this piece by Miller and Stone at first left me speechless with incredulity. This would appear to be the perfect scam (or business model) - getting people to pay real money for a product that doesn't exist. We're talking about virtual goods with a marginal cost of zero and a profit margin of 100%. The virtual goods are things like swords and spells in virtual fantasy realms, or...

In Restaurant City, a game by Playfish on Facebook, 18 million active users manage their own cafe and stock it with virtual casseroles and cakes. In Zynga’s game FarmVille, 62 million agrarian dreamers cultivate a farm, plant squash seeds and harvest their crops with tractors. (the figure shows a consumer with her cat, Demon Baby, bought for the game Pet Society.)

Crazy? Maybe not:

...strong — and somewhat rational — motives are at work. Users of social networks can buy one another gifts, like images of flowers and birthday cakes, typically for a dollar each. Facebook recently expanded its gift store to allow other companies to list their virtual wares, like greeting cards...“It’s not about the good itself, it’s about the underlying human emotion or desire,” said Moshe Koyfman, a principal at Spark Capital, which has invested in two virtual-goods start-ups. “The recipient knows the person took time, picked something meaningful and spent money on it.”

Some game fans claim that in some cases, virtual goods can be better than the real thing. Jamie Kwong, a 13-year-old in Altadena, Calif., spends hours a week on a “paper doll” site called Stardoll, buying dresses and handbags. She created Juillet606, with brown eyes and hair to match her own. Unlike the actual paper dolls she used to play with, the tabs do not rip off....“With Stardoll it all stays on there, my brother can’t get on it, and everything is good,” she said.

Maybe we should view this as the ultimate "Green" consumer product - money spent with zero environmental impact (if you accept that the energy sucking infrastructure of the internet would be there anyway).

Genes that influence our adaptability to changing rewards

Krugel et al show that a genetic change that leads to replacement of the amino acid valine with methionine in an enzyme regulating brain dopamine levels alters the flexible adaptation of reward based learning.

We show a behavioral advantage for the phylogenetically ancestral Val/Val genotype in an instrumental reversal learning task that requires rapid and flexible adaptation of decisions to changing reward contingencies in a dynamic environment...we discovered that a higher and more flexible learning rate underlies the advantage of the Val/Val genotype. Model-based fMRI analysis revealed that greater and more differentiated striatal fMRI responses to prediction errors reflect this advantage on the neurobiological level. Learning rate-dependent changes in effective connectivity between the striatum and prefrontal cortex were greater in the Val/Val than Met/Met genotype, suggesting that the advantage results from a downstream effect of the prefrontal cortex that is presumably mediated by differences in dopamine metabolism. These results show a critical role of dopamine in processing the weight a particular prediction error has on the expectation updating for the next decision.

Like us, monkeys don't like computer faces that are 'too real'.

Synthetic agents such as androids or computer-animated characters can elicit responses from us (mainly of positive emotional valence) similar to those elicited by real humans as long as they have a low resemblance to humans. But, if these agents become too realistic, we find them unsettling. This feeling of eeriness is known as the “uncanny valley” and is associated with entities that elicit the concept of a human, but do meet all of the requirements for being one. Steckenfinger and Ghazanfar find that monkeys apparently have the same kind of response.

Very realistic human-looking robots or computer avatars tend to elicit negative feelings in human observers. This phenomenon is known as the “uncanny valley” response. It is hypothesized that this uncanny feeling is because the realistic synthetic characters elicit the concept of “human,” but fail to live up to it. That is, this failure generates feelings of unease due to character traits falling outside the expected spectrum of everyday social experience. These unsettling emotions are thought to have an evolutionary origin, but tests of this hypothesis have not been forthcoming. To bridge this gap, we presented monkeys with unrealistic and realistic synthetic monkey faces, as well as real monkey faces, and measured whether they preferred looking at one type versus the others (using looking time as a measure of preference). To our surprise, monkey visual behavior fell into the uncanny valley: They looked longer at real faces and unrealistic synthetic faces than at realistic synthetic faces.

Our left and right hemispheres can selectively track expected value

Palminteri et al. show that the expected values of two options, which were cued by visual symbols and chosen with either the left or right hand, enhanced activity, respectively, in the right or left (i.e. contralateral) ventral prefrontal cortex, thus respecting the topography of the brain systems elicited by the available options.

A main focus in economics is on binary choice situations, in which human agents have to choose between two alternative options. The classical view is that decision making consists of valuating each option, comparing the two expected values, and selecting the higher one. Some neural correlates of option values have been described in animals, but little is known about how they are represented in the human brain: are they integrated into a single center or distributed over different areas? To address this issue, we examined whether the expected values of two options, which were cued by visual symbols and chosen with either the left or right hand, could be distinguished using functional magnetic resonance imaging. The two options were linked to monetary rewards through probabilistic contingencies that subjects had to learn so as to maximize payoff. Learning curves were fitted with a standard computational model that updates, on a trial-by-trial basis, the value of the chosen option in proportion to a reward prediction error. Results show that during learning, left and right option values were specifically expressed in the contralateral ventral prefrontal cortex, regardless of the upcoming choice. We therefore suggest that expected values are represented in a distributed manner that respects the topography of the brain systems elicited by the available options.

Genetic enhancement of memory.

Just as I was thinking about doing a post on the recent paper by Wang et al. showing improved memory performance in rats genetically engineered to over-express a subunit of a synaptic receptor gene, my son-in-law J.T. Smith pointed out a very nice summary of the work in h+ magazine.

We can generate a novel body image internally, without external feedback

Our body image, as well as our body's location in space, can be manipulated by altering sensory feedback from the environment. Now Moseley and Brugger make the amazing observation that we can change our sense of ownership and agency to include impossible movements, independent of sensory feedback from the body or external feedback about task performance.

The feeling we have of our own body, sometimes called “body image,” is fundamental to self-awareness. However, by altering sensory input, the body image can be modified into impossible configurations. Can impossible movements of the body image be conjured solely via internally generated mechanisms, and, if so, do the structural characteristics of the body image modify to accommodate the new movements? We encouraged seven amputees with a vivid phantom arm to learn to perform a phantom wrist movement that defied normal anatomical constraints. Four reported success. Learning the impossible movement coincided in time with a profound change in the body image of the arm, including a sense of ownership and agency over a modified wrist joint. Remarkably, some previous movements and functional tasks involving the phantom arm became more difficult once the shift in body image had occurred. Crucially, these introspective reports were corroborated by robust empirical data from motor imagery tasks, about which amputees were naïve and to which assessors were blind. These results provide evidence that: a completely novel body image can be constructed solely by internally generated mechanisms; that the interdependence between movement repertoire and structural constraints of the body persists even when the structural constraints imparted by the body do not—the body image we construct still constrains imagined movements; and that motor learning does not necessarily need sensory feedback from the body or external feedback about task performance.

Social functions of gossip

John Tierney does a nice piece on one sort of contemporary ethnography, in this case dealing with gossip as reputational warfare.

...this time enthnographers have returned from the field with footage of a truly savage native ritual: teachers at an elementary school in the Midwest dishing about their principal behind her back.

The modern dating game.

Two fascinating articles (Brooks, who points to Yang) on how how technology has so fundamentally changed the ways we seek both one time and long term partners. I've tried the Grindr iPhone App described below by Yang (its GPS feature doesn't work worth diddly... it told me a handsome guy was 2,000 ft. away, and after we began to set up a meeting, he turned out to be in Iowa!). It is clear, as noted by Brooks, that all this technology "seems to threaten the sort of recurring and stable reciprocity that is the building block of trust."

So there’s this iPhone app called Grindr. It’s a GPS-enabled social-networking service for gay men. It tells you how many feet away a possible hookup is standing. Each profile comes with a picture, a tagline, the relevant stats, and a declaration of interest. You scroll through a column of heads and torsos arranged in descending order of proximity, tapping on the ones that seem promising and chatting with the ones who want the same things you do. As you make your way through the city, the menu of men reshuffles, and the erotic terrain updates in real time.

Has the search for erotic gratification ever been so efficient? Until recently, being a cad or coquette took a lot of work: You needed to buy a little black book, and you had to go around filling it, and then you had to schedule your calls for a time when the target of your seduction was likely to be at home. The less-self-assured daters in New York faced the sickening anxiety of the first phone call, or the cold approach in the bar. There were palliatives designed to help people cope—the newspaper personal ads, the paid dating services, the dirty videos and magazines—but they were generally understood to be the province of weirdos and losers.

No more. The social technologies that assist in dating and mating today are more than palliatives—they’ve changed the nature of the game. If the cold approach is more than you can deal with, put up a Craigslist ad, or join OkCupid, Manhunt, or Nerve. If the phone call makes you nervous, send a text message. And while you’re at it, send a text message to a half-dozen other people with everyone’s favorite late-night endearment: “where u at?” If nothing works out and you find yourself alone at home again, simply fire up XTube or YouPorn and choose from an endless variety of positions to help you reach a late-night climax.

Asperger's syndrome to become Autism spectrum disorder?

Claudia Wallis does an article on the proposal to drop the name "Asperger's syndrome,' folding it, along with the term "pervasive developmental disorder" into the term "Autism spectrum disorder." The simple fact appears to be that "nobody has been able to show consistent differences between what clinicians diagnose as Asperger’s syndrome and what they diagnose as mild autistic disorder." The not so minor problem is that the general population views "Asperger's syndrome" more positively than autism, and the term has developed its own brand identity. "The Asperger’s diagnosis is used by health insurers, researchers, state agencies and schools — not to mention people with the disorder, many of whom proudly call themselves Aspies." On the other hand Ari Ne’eman, 21 - an activist who founded the Autistic Self-Advocacy Network, a 15-chapter organization he has built while in college - notes “My identity is attached to being on the autism spectrum, not some superior Asperger’s identity. I think the consolidation to one category of autism spectrum diagnosis will lead to better services.”

The dynamics of social inequality.

Borgerhoff Mulder et al. show that wealth inequality in 21 historical and contemporary "small-scale societies" is determined by the intergenerational transmission of different types of assets. From the editor's summary:

Wealthy contemporary societies exhibit varying extents of economic inequality, with the Nordic countries being relatively egalitarian, whereas there is a much larger gap between top and bottom in the United States. Borgerhoff Mulder et al. build a bare-bones model describing the intergenerational transmission of three different types of wealth—based on social networks, land and livestock, and physical and cognitive capacity—in four types of small-scale societies in which livelihoods depended primarily on hunting, herding, farming, or horticulture. Parameter estimates from a large-scale analysis of historical and ethnographic data were added to the model to reveal that the four types of societies display distinctive patterns of wealth transmission and that these patterns are associated with different extents of inequality.

Here is the article abstract:

Small-scale human societies range from foraging bands with a strong egalitarian ethos to more economically stratified agrarian and pastoral societies. We explain this variation in inequality using a dynamic model in which a population’s long-run steady-state level of inequality depends on the extent to which its most important forms of wealth are transmitted within families across generations. We estimate the degree of intergenerational transmission of three different types of wealth (material, embodied, and relational), as well as the extent of wealth inequality in 21 historical and contemporary populations. We show that intergenerational transmission of wealth and wealth inequality are substantial among pastoral and small-scale agricultural societies (on a par with or even exceeding the most unequal modern industrial economies) but are limited among horticultural and foraging peoples (equivalent to the most egalitarian of modern industrial populations). Differences in the technology by which a people derive their livelihood and in the institutions and norms making up the economic system jointly contribute to this pattern.

The best way to measure brain signals...

Kind of a techie point, but I thought it interesting... Sirotin et al. have measured both increases in blood oxygenation and blood volume in the brains of two macaques while they performed a visual task. They find that blood-volume change is a better signal to use in brain imaging because it seems to be more closely linked to neural activity, occurring even before changes in blood oxygenation.

Dog smarts

An engaging article on dog intelligence in Sunday's New York Times. And on the subject of dog smarts, a new and engaging book: Darwin's Dogs: How Darwin's Pets Helped Form a World-Changing Theory of Evolution (Frances Lincoln: 2009), by Emma Townshend.

Wicked Manors....

I arrived at MindBlog's winter home in the Wilton Manors section of Fort Lauderdale just in time for Halloween. The photos (the one on the left being "Bride of Frankenstein with bride's maids") are from the Halloween street festival "Wicked Manors" held on the main street Wilton Drive, which is lined by gay bars and restaurants.

Prosociality in large human groups more likely due to culture than to genetics.

Bell et al. think about whether human prosocial behaviors such as food sharing, taxation, and warfare - nearly completely absent in other vertebrates - are more plausibly explained as arising from to cultural or genetic selection during competition among large groups. They use the term "group-level selection" to refer to the scenario in which groups differ in the frequency of individuals who are willing to sacrifice their own labor, time, or safety in ways that promote the competitive ability of the residential group, so that over time groups with higher frequencies of such “altruists” may tend to replace groups with fewer. A key point is that:

Selection for culturally-prescribed altruists occurs through the same process as for genes: groups of altruists leave more daughter societies. However, one advantage that cultural variation has over genetic is that it does not require violent inter-group competition, nor group extinctions. If failed groups were incorporated routinely into successful ones, conformist transmission and other forms of resocialization of failed groups can lead to effective cultural selection on groups even though such a pattern will generate rates of migration that keep genetic F_ST (a measure of genetic differentiation between populations) very low between neighbors. Thus selection on culture can be powerful precisely when genetic selection at the group level is weakest.

The meat of the article is formal calculation using the Price equation (don't ask...) that suggests much greater scope for cultural rather than genetic group-level selection in allowing altruism to arise.

A drug that protects prefrontal cortex from stress.

Here is an interesting piece from Hains et al. on stress and the prefrontal cortex. They use a rat model and a restraint stress paradigm to show that a drug can inhibit the working memory impairment and degenerative architectural changes caused by the stress.

The prefrontal cortex regulates behavior, cognition, and emotion by using working memory. Prefrontal functions are impaired by stress exposure. Acute, stress-induced deficits arise from excessive protein kinase C (PKC) signaling, which diminishes prefrontal neuronal firing. Chronic stress additionally produces architectural changes, reducing dendritic complexity and spine density of cortico-cortical pyramidal neurons, thereby disrupting excitatory working memory networks. In vitro studies have found that sustained PKC activity leads to spine loss from hippocampal-cultured neurons, suggesting that PKC may contribute to spine loss during chronic stress exposure. The present study tested whether inhibition of PKC with chelerythrine before daily stress would protect prefrontal spines and working memory. We found that inhibition of PKC rescued working memory impairments and reversed distal apical dendritic spine loss in layer II/III pyramidal neurons of rat prelimbic cortex. Greater spine density predicted better cognitive performance, the first direct correlation between pyramidal cell structure and working memory abilities. These findings suggest that PKC inhibitors may be neuroprotective in disorders with dysregulated PKC signaling such as bipolar disorder, schizophrenia, post-traumatic stress disorder, and lead poisoning—conditions characterized by impoverished prefrontal structural and functional integrity.