Evolutionary biology: Excitation over jelly nerves

Interesting to see that evolution can and does take fundamentally different pathways, especially in terms of nervous system which was believed to have only one direction, from simple nervous system to complex human brain.
http://www.nature.com/news/jelly-genome-mystery-1.15264

also the full article here:
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13400.html

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Keeping up my end of the conversation with Chris

So I got into a conversation on Chris's Linguistics Blog, and I think it would be kinder not to make big comments on his blog. So my half of the conversation will be over here and I'll link to his thoughts so that the conversation can be followed.

It all started here with Chris's discussion of case assignment. I asked a couple questions in the comments. He responded directly here and you can read my comments at the bottom and now Chris has asked me some questions.

Here's his question:

With that said, Andrea asks about a potential genetic substrate for language learning, and from what I recall reading and hearing about in linguistic anthropology, there has been suggestion of precisely that. If universal grammar does exist and we do have this ability to learn any human language, there may perhaps be some genetic substrate for language learning...a language acquisition gene, if you will. Andrea mentions that this would be "a very strong claim given the latest neuroscience." I don't think that I'm familiar with the material that that references, so could you fill me in on that please Andrea? I'd really like to know about it.

I'm going to rephrase the question as I hear it: Given what we know about the brain, what are the chances that we have a language acquisition gene (that produces or is a language acquisition device)?

And for the sake of time and getting back to my gender and langauge book review which is on hold, I will answer this subset of the problem: Getting something into the genes.
Click on to read my answer.

Evolutionary theory tells us a story like this: organisms may have gene mutations that are adaptive. As such, those organisms with the adaptive mutation are more likely to survive, more likely to have progeny who may also have that mutation. Lather, rinse, repeat and mutations accrete. Woohoo! This is cool!

Moving on to language and genes--
When we look at our primate relatives, we do not see nearly the symbolic capacity that we humans have. (Even decades of work by Savage-Rumbaugh with Kanzi the bonobo hasn't gotten very far. There is no danger of bonobos starting libraries or building nukes anytime soon.) In other words, somewhere between there and here, language evolved in.

Although this might send a true Chomskian shrieking, from an evolutionary perspective language must be a communicative act. Why?

Let's say that in the primordial world, homonid "John" won the genetic lottery and has the language acquisition gene (LAG). The first! The only! Oh wait. The only? He has all the "underlying grammar" waiting to be set but there is no speech community around him to set the parameters. That mutation is wholy obscured, not evident to any of the chicks. Turns out his lottery pays off in funny money, so his Benz is locked in the garage.

John's buddy "Tom" won the other genetic lottery and can throw rocks with stunning accuracy. Able to fend off predators, knock down fruit, and hunt squirrels, the chicks dig Tom. "Tom, take me for a ride in your Hummer!" they shout as John looks forlornly along. So we have John, average in every other way and Tom, community stud. Tom's genes advance, John's? Well, we don't know. So the first problem with the LAG is the chances of it continuing in the gene pool on its own are not looking good.

To sum up, it appears that LAD/LAG proponents look at the universality of language acquisition and say, "It must be in the genes!" When this was first said 50 years ago, genetics was this mystery black box term. But it's 2006. To say it is in the genes requires that the sayers be serious about that, to study what that implies, and to my (possibly egocentric) mind, get around the problem I proposed--the lack of a speech community in which to demonstrate a LAG/LAD as a fitness indicator.

Tune in next time for: General cognition/"Up from movement"

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World explodes

Ok it doesn't. But the scouring of the web for NLRG worthy posts was really hard for a while and now I'm snowed under with interesting articles.

The first is really just a scientific tragedy that is fairly sobering. The NYTimes reports on the sentencing of University of Vermont's Eric Poehlman. After one of his lab tech turned him in and investigation showed that Poehlman had been making up data to support his hypotheses for a decade. Sad really.

I think the following article is reporting on single cell studies in monkey that connect sounds to reward. Click on to read quotes from the report.

“When something starts to predict a good outcome is going to happen, the sensory part of the brain that responds to those events starts to respond more strongly, making it easier for the brain to cause a behavioral response,” says Dr. David T. Blake, neuroscientist at the Medical College of Georgia and lead author on a study in the Oct. 19 issue of Neuron.

By monitoring the action potentials of about a dozen key neurons in monkey test subjects, researchers found neuronal responsiveness increases dramatically after just a few training sessions.

These neuronal fireworks were short-lived, replaced by a rewiring of the brain that shows the animal has learned, Dr. Blake says.

In the few monkeys that initially didn’t make the connection that a change in pitch in a series of sounds meant they were getting a juice reward, no brain changes occurred.

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Fathers and language learning etc.

Newscientist.com comes through with not one but two interesting new findings. Haven't dug through to find the original papers, but worth thinking about.

1) Language learning focuses on infant-mother interaction pretty heavily and as far back as Jespersen (1922), fathers have been written off as having little bottom up influence in child language acquisition. Well, Lynne Vernon-Feagans at the University of North Carolina, Chapel Hill peeked in on 2 year olds and their time with daddy. Looks like fathers have some influence.

2) The reporting on this second paper looks shoddy because there appears to be a 10% decrease in right superior temporay gyrus of verbally abused children and this is supposed to be a language center. Language is usually lateralized to the left so either a) they said right and meant left or b) the right also has some language specific regions. I haven't researched this much further at this point, but the new scientist is reporting that the researcher hints at a causal relationship between the decrease in size in this area and verbal ability. Pretty strong claims if you ask me.

Here's the presentation abstract:
Title:

Exposure to childhood verbal abuse is associated with abnormalities in auditory cortex and hippocampus
Location:

Georgia World Congress Center: Halls B3-B5
Authors:

*M. H. TEICHER1, A. TOMODA1, K. LIBESNEY1, A. POLCARI1, C. P. NAVALTA1, N. SODATO2;
1Dept Psychiatry, Harvard Med Sch, Belmont, MA, 2Cerebral Research, National Institute for Physiological Sciences, Okazaki, Aichi, JAPAN.
We have recently reported that early exposure to parental verbal abuse (VA) is associated with psychiatric symptomatology in early adulthood that is comparable to the effects of exposure to non-familial sexual abuse and witnessing of domestic violence (Teicher et al 2006). In the current study we examined the association between exposure to VA and measures of brain morphometry.
The sample consisted of 17 healthy unmedicated right-handed subjects (6M/11F [18-22 years of age]) with high-level exposure to VA, but without exposure to any other form of trauma, and 17 carefully-matched healthy controls. Volumetric brain images were acquired with a 3T Siemens Trio scanner and processed using optimized voxel-based morphometry (VBM) for regional differences in grey matter volume (GMV).
There were significant reductions in GMV of right (-9.9%) and left (-9.2%) superior temporal gyri (STG) of abused subjects. Degree of exposure correlated with GMV of left STG for the entire sample (r=-0.38, p=0.02). Measures of verbal memory correlated with degree of GMV reduction in left STG (r=-0.39). Males were more strongly affected, and also had a 15.9% and 13.8% reduction in left and right superior frontal gyrus.
A major consequence of exposure to VA was limbic irritability, characterized by symptoms of dissociation, sensory disturbances, and automatisms. Ratings of limbic system irritiability on the limbic system checklist correlated strongly with GMV deficits in left (p < 0.0001) and right (p < 0.0001) hippocampus. Subjects exposed to high levels of VA also had a 13-point reduction in verbal IQ.
This study suggests that exposure to parental VA may significantly impact brain development targeting superior temporal gyrus and auditory cortex, which are known to be plastic structure. Further, there is evidence for correlative abnormalities in hippocampus, which may help to explain their heightened degree of vulnerability to psychiatric symptomatology.

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Bilingualism in the Brain

Over at Dartmouth; via Lingformant

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Human Brain Functions Like A Digital Computer

Read all about it.

[Time flies when school starts] Will try to be better about updating.

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Beauty on my mind

So composite faces and prototypical faces are the ones judged to be beautiful. And the thought was that it is evolutionarily advantageous to not be attracted to non-average, ie disfigured people who might be a let fit mate.

It looks like Piotr Winkielman of the University of California, San Diego put non-reproductive stimuli in front of people and in short "...the less time it took participants to classify a pattern, the more attractive they judged it."

This is of interest to our group because we're always interested in seeing more general cognitive functions being explanations for what was thought to be a more specific "need" or "adaptation". And if you've been reading along, this tendency is because generative linguistics has been pushing for grammar specific neural networks where our understanding of the brain makes that level of specificity highly unlikely. Studies like this seem to point out that even mate selection based on "beauty" may rest on a more general pattern recognition system.

Science Blog covers the story. Click on for quotes from Science Blog and a link to the paper.

"It seems you don't need to postulate an unconscious calculator of mate value or any other 'programmed-brain' argument to explain why prototypical images are more attractive," Winkielman said. "The mental mechanism appears to be extremely simple: facilitate processing of certain objects and they ring a louder bell.

"This parsimonious explanation," he said, "accounts for cultural differences in beauty – and historical differences in beauty as well – because beauty basically depends on what you've been exposed to and what is therefore easy on your mind."

Link to the paper with subscription to Psychological Sciences

ABSTRACT—People tend to prefer highly prototypical stimuli—a phenomenon referred to as the beauty-in-averageness effect. A common explanation of this effect proposes that prototypicality signals mate value. Here we present three experiments testing whether prototypicality preference results from more general mechanisms—fluent processing of prototypes and preference for fluently processed stimuli. In two experiments, participants categorized and rated the attractiveness of random-dot patterns (Experiment 1) or common geometric patterns (Experiment 2) that varied in levels of prototypicality. In both experiments, prototypicality was a predictor of both fluency (categorization speed) and attractiveness. Critically, fluency mediated the effect of prototypicality on attractiveness, although some effect of prototypicality remained when fluency was controlled. The findings were the same whether or not participants explicitly considered the pattern's categorical membership, and whether or not categorization fluency was salient when they rated attractiveness. Experiment 3, using the psychophysiological technique of facial electromyography, confirmed that viewing abstract prototypes elicits quick positive affective reactions.

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