March 27, 2008

The first hominin of Europe

hominin.jpgIn this week’s Nature, an article reports on the discovery of a human lower jaw associated with stone tools and animal bones from the Sima del Elefante in northern Spain. The finds have been dated to between 1.1 and 1.2 million years using a variety of dating techniques, making the site the oldest and most accurately dated record of human occupation in Europe.

From the article:

Here we report the discovery of a human mandible associated with an assemblage of Mode 1 lithic tools and faunal remains bearing traces of hominin processing, in stratigraphic level TE9 at the site of the Sima del Elefante, Atapuerca, Spain. Level TE9 has been dated to the Early Pleistocene (approximately 1.2–1.1 Myr), based on a combination of palaeomagnetism, cosmogenic nuclides and biostratigraphy. The Sima del Elefante site thus emerges as the oldest, most accurately dated record of human occupation in Europe, to our knowledge.

The study of the human mandible suggests that the first settlement of Western Europe could be related to an early demographic expansion out of Africa. The new evidence, with previous findings in other Atapuerca sites (level TD6 from Gran Dolina), also suggests that a speciation event occurred in this extreme area of the Eurasian continent during the Early Pleistocene, initiating the hominin lineage represented by the TE9 and TD6 hominins.

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March 5, 2008

Gene variants may increase risk of anxiety disorders

anx.jpegFrom physorg: Massachusetts General Hospital (MGH) researchers – in collaboration with scientists at the University of California at San Diego and Yale University – have discovered perhaps the strongest evidence yet linking variation in a particular gene with anxiety-related traits. In the March issue of Archives of General Psychiatry, the team describes finding that particular versions of a gene that affects the activity of important neurotransmitter receptors were more common in both children and adults assessed as being inhibited or introverted and also were associated with increased activity of brain regions involved in emotional processing.

“We found that variations in this gene were associated with shy, inhibited behavior in children, introverted personality in adults and the reactivity of brain regions involved in processing fear and anxiety,” says Jordan Smoller, MD, ScD, of the MGH Department of Psychiatry, the report’s lead author. “Each of these traits appears to be a risk factor for social anxiety disorder, the most common type of anxiety disorder in the U.S.”

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New issue: Self & Identity

selfidentity.gifA new issue of Self & Identity is out, with articles including topics such as cultural differences in self-esteem, the self in change, and the self in life transitions.

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January 30, 2008

God on the brain

From BBC (and read exciting transcript): Rudi Affolter and Gwen Tighe have both experienced strong religious visions. He is an atheist; she a Christian. He thought he had died; she thought she had given birth to Jesus. Both have temporal lobe epilepsy.

Like other forms of epilepsy, the condition causes fitting but it is also associated with religious hallucinations. Research into why people like Rudi and Gwen saw what they did has opened up a whole field of brain science: neurotheology.

The connection between the temporal lobes of the brain and religious feeling has led one Canadian scientist to try stimulating them. (They are near your ears.) 80% of Dr Michael Persinger’s experimental subjects report that an artificial magnetic field focused on those brain areas gives them a feeling of ‘not being alone’. Some of them describe it as a religious sensation.

His work raises the prospect that we are programmed to believe in god, that faith is a mental ability humans have developed or been given. And temporal lobe epilepsy (TLE) could help unlock the mystery.

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January 9, 2008

Ageing makes the imagination wither

cognition,human nature — thomasr @ 7:36 am

Memory decline in old age may also mean a less vivid imagination. Stitching together personal details gets harder as we get older. Old age does more than stealthily steal away our most cherished memories: it also seems to diminish our ability to imagine things.

This finding, detailed in the January issue of the journal Psychological Science 1, supports the ‘prospective brain’ hypothesis, the idea that imagining the future and remembering the past rely on the same neural machinery.

“One implication of this study is that imagining is quite closely related to, and dependent on, remembering, perhaps more so than we previously realized,” says Dan Schacter of Harvard University.

In the study, Schacter and his team asked groups of young and old participants, with average ages of 25 and 72, respectively, to recount a personal episode from their past or imagine a personal experience in their future in response to cue words.

Nature News

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January 4, 2008

Decision making, impulsivity and time perception

Time is an important dimension when individuals make decisions. Specifically, the time until a beneficial outcome can be received is viewed as a cost and is weighed against the benefits of the outcome.

We propose that impulsive individuals experience time differently, that is with a higher cost. Impulsive subjects, therefore, overestimate the duration of time intervals and, as a consequence, discount the value of delayed rewards more strongly than do self-controlled individuals.

The literature on time perception and impulsivity, however, is not clear cut and needs a better theoretical foundation. Here, we develop the theoretical background on concepts of time perception, which could lead to an empirically based notion of the association between an altered sense of time and impulsivity.

Article by Marc Wittmann and Martin P. Paulus in Trends in Cognitive Sciences, Volume 12, Issue 1, January 2008, Pages 13-16

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December 14, 2007

Personality & Individual Differences — new issue

human nature,journal,personality — thomasr @ 3:28 am

A new issue of the journal Personality and Individual Differences (Volume 44, Issue 3) hosts a number of interesting articles including:

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Cognition & Emotion new issue

A new issue of Cognition & Emotion is out, including articles on emotional memory and awareness, music and emotions, and anger-induction methods.

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December 11, 2007

The trivial function of sleep

Rest in poikilothermic animals is an adaptation of the organism to adjust to the geophysical cycles, a doubtless valuable function for all animals. In this review, we argue that the function of sleep could be trivial for mammals and birds because sleep does not provide additional advantages over simple rest. This conclusion can be reached by using the null hypothesis and parsimony arguments.

First, we develop some theoretical and empirical considerations supporting the absence of specific effects after sleep deprivation. Then, we question the adaptive value of sleep traits by using non-coding DNA as a metaphor that shows that the complexity in the design is not a definitive proof of adaptation.

We then propose that few, if any, phenotypic selectable traits do exist in sleep. Instead, the selection of efficient waking has been the major determinant of the most significant aspects in sleep structure. In addition, we suggest that the regulation of sleep is only a mechanism to enforce rest, a state that was challenged after the development of homeothermy.

As a general conclusion, there is no direct answer to the problem of why we sleep; only an explanation of why such a complex set of mechanisms is used to perform what seems to be a simple function. This explanation should be reached by following the evolution of wakefulness rather than that of sleep. Sleep could have additional functions secondarily added to the trivial one, although, in this case, the necessity and sufficiency of these sleep functions should be demonstrated.

The trivial function of sleep. R.V. Rial, Maria C. Nicolau, Antoni Gamundi, Mourad Akaarir, Sara Aparicio, Celia Garau, Silvia Tejada, Catalina Roca, Lluis Gene, David Moranta, Susana Esteban, 2007. Sleep Medicine Reviews 11(4):311-325.

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Belief, disbelief and uncertainty activate distinct brain regions

The capacity of the human mind to believe or disbelieve a statement is a powerful force for controlling both behavior and emotion, but the basis of these states in the brain is not yet understood. A new study found that belief, disbelief and uncertainty activate distinct regions of the brain, with belief/disbelief affecting areas associated with the pleasantness/unpleasantness of tastes and odors. The study will publish online in the Annals of Neurology, the official journal of the American Neurological Association.

Led by Sam Harris of the University of California, Los Angeles, the study involved 14 adults who underwent functional MRI scans during which they were presented with short statements that they had to evaluate as true, false or undecided. Each participant underwent three scans while they evaluated statements from a broad variety of categories such as mathematical, geographical, autobiographical, religious and factual. The statements were designed to be clearly true, false or undecidable.

Contrasting belief and disbelief trials yielded increased signal in the (VMPFC), which is involved in linking factual knowledge with emotion. “The involvement of the VMPFC in belief processing suggests an anatomical link between the purely cognitive aspects of belief and human emotion and reward,” the authors state. The fact that ethical belief showed a similar pattern of activation to mathematical belief suggests that the physiological difference between belief and disbelief is not related to content or emotional associations, they note.

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December 10, 2007

Neurons in the frontal lobe may be responsible for rational decision-making

decision making,human nature,neuroscience — thomasr @ 7:17 am

From physorg.com — You study the menu at a restaurant and decide to order the steak rather than the salmon. But when the waiter tells you about the lobster special, you decide lobster trumps steak. Without reconsidering the salmon, you place your order—all because of a trait called “transitivity.”

“Transitivity is the hallmark of rational economic choice,” says Camillo Padoa-Schioppa, a postdoctoral researcher in HMS Professor of Neurobiology John Assad’s lab. According to transitivity, if you prefer A to B and B to C, then you ought to prefer A to C. Or, if you prefer lobster to steak, and steak to salmon, then you will prefer lobster to salmon.

Padoa-Schioppa is lead author on a paper that suggests this trait might be encoded at the level of individual neurons. The study, which appears online Dec. 9 in Nature Neuroscience, shows that some neurons in a part of the brain called the orbitofrontal cortex encode economic value in a “menu invariant” way. That is, the neurons respond the same to steak regardless if it’s offered against salmon or lobster.

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Researchers can read thoughts to decipher what a person is actually seeing

From physorg.com — Following ground-breaking research showing that neurons in the human brain respond in an abstract manner to particular individuals or objects, University of Leicester researchers have now discovered that, from the firing of this type of neuron, they can tell what a person is actually seeing.

The original research by Dr R Quian Quiroga, of the University’s Department of Engineering, showed that one neuron fired to, for instance, Jennifer Aniston, another one to Halle Berry, another one to the Sydney Opera House, etc. The responses were abstract. For example, the neuron firing to Halle Berry responded to several different pictures of her and even to the letters of her name, but not to other people or names.

This result, published in Nature in 2005 and selected as one of the top 100 scientific stories of the year by Discover Magazine, came from data from patients suffering from epilepsy. As candidates for epilepsy surgery, they are implanted with intracranial electrodes to determine as accurately as possible the area where the seizures originate. From that, clinicians can evaluate the potential outcome of curative surgery.

Dr Quian Quiroga’s latest research, which has appeared in the Journal of Neurophysiology, follows on from this. Dr Quian Quiroga explained:

“For example, if the ‘Jennifer Aniston neuron’ increases its firing then we can predict that the subject is seeing Jennifer Aniston. If the ‘Halle Berry neuron’ fires, then we can predict that the subject is seeing Halle Berry, and so on. “To do this, we used and optimised a ‘decoding algorithms’, which is a mathematical method to infer the stimulus from the neuronal firing. We also needed to optimise our recording and data processing tools to record simultaneously from as many neurons as possible. Currently we are able to record simultaneously from up to 100 neurons in the human brain.

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Are Humans Evolving Faster?

From physorg.com –  Researchers discovered genetic evidence that human evolution is speeding up – and has not halted or proceeded at a constant rate, as had been thought – indicating that humans on different continents are becoming increasingly different.

We used a new genomic technology to show that humans are evolving rapidly, and that the pace of change has accelerated a lot in the last 40,000 years, especially since the end of the Ice Age roughly 10,000 years ago,” says research team leader Henry Harpending, a distinguished professor of anthropology at the University of Utah.

Harpending says there are provocative implications from the study, published online Monday, Dec. 10 in the journal Proceedings of the
National Academy of Sciences:

“We aren’t the same as people even 1,000 or 2,000 years ago,” he says, which may explain, for example, part of the difference between Viking invaders and their peaceful Swedish descendants. “The dogma has been these are cultural fluctuations, but almost any temperament trait you look at is under strong genetic influence.”

“Human races are evolving away from each other,” Harpending says. “Genes are evolving fast in Europe, Asia and Africa, but almost all of these are unique to their continent of origin. We are getting less alike, not merging into a single, mixed humanity.” He says that is happening because humans dispersed from Africa to other regions 40,000 years ago, “and there has not been much flow of genes between the regions since then.”

“Our study denies the widely held assumption or belief that modern humans [those who widely adopted advanced tools and art] appeared 40,000 years ago, have not changed since and that we are all pretty much the same. We show that humans are changing relatively rapidly on a scale of centuries to millennia, and that these changes are different in different continental groups.”

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November 26, 2007

Social neuroeconomics: the neural circuitry of social preferences

Combining the methods of neuroscience and economics generates powerful tools for studying the brain processes behind human social interaction. We argue that hedonic interpretations of theories of social preferences provide a useful framework that generates interesting predictions and helps interpret brain activations involved in altruistic, fair and trusting behaviors. These behaviors are consistently associated with activation in reward-related brain areas, such as the striatum, and with prefrontal activity implicated in cognitive control, the processing of emotions, and integration of benefits and costs, consistent with resolution of a conflict between self-interest and other-regarding motives.

Fehr & Camerer in Trends in Cognitive Science 2007 Oct ; 11(10): 419-27

Hubmed

PDF of article

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November 22, 2007

Consciousness & mind related articles in Psychological Science

human nature,journal — thomasr @ 4:54 pm

Psychological Science is out with a new issue that brings several articles relevant to the SCR audience. Here, we bring some selected abstracts.

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November 13, 2007

Rare great ape fossil challenges theory of primate evolution

evolution,human nature — thomasr @ 4:21 am

From physorg.com: Archaeologists have discovered the ancient jawbone of what appears to be a new species of ape that was very close to the last common ancestor of gorillas, chimpanzees and humans, a study released Monday said. The 10-million year-old fossil, complete with 11 teeth, was recovered from volcanic mud deposits in Kenya’s Nakali region on the eastern edge of the Rift Valley in 2005 by a team of Japanese and Kenyan researchers. The researchers say the fossil fills what was until recently something of a void in the fossil record, and challenges one of the working assumptions of primate evolution.

Genetic studies suggest that humans and great apes split from a common ancestor about eight million years ago, but paleontologists have struggled to find fossils for the ancestors of modern African great apes for the past 13 million years. However scientists found plenty of fossil evidence for great apes in Europe and Asia during that period and they also noted some similarities between some of those apes and contemporary African apes.

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November 9, 2007

Brain Chemicals Involved In Aggression Identified

From ScienceDaily (Nov. 7, 2007) — School shootings. Muggings. Murder. Road rage. After decreasing for more than a decade, the rate of violent crime in the United States has begun to inch up again. According to the FBI’s Uniform Crime Reporting Program, violent crime rose 2.3 percent in 2005 and 1.9 percent in 2006, the first steady increase since 1993.

And new studies are helping scientists gain deeper insight into the neurobiology of aggression and violence. One analysis of brain imaging studies has revealed that brain structures involved in making moral judgments are often damaged in violent individuals. Another study involving teenage boys suggests that disruptions in a brain region linked to impulsive, aggressive behavior may underlie a certain type of violent, reactive behavior.

Still other research has shed new light on the role that certain brain chemicals play in aggressive behavior, including in maternal aggression. And new animal studies reveal that aggressive encounters cause changes in the brains of aggressors as well as their victims that increase vulnerability to depression and immune-related illnesses.

“Violence in our society is a major concern, indeed, a national health problem,” says Craig Ferris, PhD, of Northeastern University in Boston. “Understanding the confluence of events, both environmental and biological, that trigger a violent act has been the focus of educators, health professionals, and scientists for decades.

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October 25, 2007

New issue: Personality and Individual Differences

A new issue of PID is out, including articles on borderline and self-regulation, black anti-white attitudes and personality, and stress reactions and personality.

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September 15, 2007

Brain stem may be key to consciousness:

From MindHacks
An article in this week’s Science News discusses whether the brain stem may play a more central role in consciousness than it’s usually given credit for.

It focuses on children with hydranencephaly, a where the cortex fails to develop in children and instead, the space is filled with cerebral spinal fluid.

Typically, affected children survive only a few months after birth, but those that do survive seem to remarkably more conscious than you would guess based on theories that suggest the cortex is where all the action happens to support consciousness.

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September 10, 2007

Initiative: Decade of the Mind

ASSC,human nature,theory — thomasr @ 3:22 am

Dear all!

I would draw your attention to the letter  ‘A Proposal for a Decade of the Mind Initiative‘ by JAMES S. ALBUS, GEORGE A. BEKEY, JOHN H. HOLLAND, NANCY G. KANWISHER, JEFFREY L. KRICHMAR, MORTIMER MISHKIN, DHARMENDRA S. MODHA, MARCUS E. RAICHLE, GORDON M. SHEPHERD, GIULIO TONONI just now published in SCIENCE VOL 317 7 SEPTEMBER 2007 page 1321.

The authors propose a Decade of the Mind initiative. According to them (they represent its steering committee) it would build on progress of the recent Decade of the Brain (1990-99) and should in short focus on four broad, but intertwined areas:

  1. Healing and protecting the mind.
  2. Understanding the mind.
  3. Enriching the mind.
  4. Modeling the mind.

I strongly agree with the view that ‘present time ripe for breakthroughs in the study of the mind’ and sure the Decade proposed is extremely opportune initiative which will also positively influence on mind research in many countries outside the USA. Even the fact of publishing the letter concerning
the idea of the Decade could help to mind research progress worldwide.

The ASSC as a whole, all its members and all who are interesting in mind/brain, psychology, cognition, computer etc sciences should without doubt intensively support the Decade of the Mind initiative.

Bravo!

Petro Gopych,
Kharkiv, Ukraine

(From the PSYCHE mailing list)

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