Smooth Pebbles

The Hormone That Helps You Read Minds

We've long accepted that hormones can make you amorous, aggressive, or erratic. But lately neuroscience has been abuzz with evidence that the hormone oxytocin -- which also acts as a neuromodulator -- can enhance at least one cognitive power: the ability to understand what others are thinking. In this week's Mind Matters (the online blog seminar on mind and brain I edit for Scientific American), Jennifer Bartz and Eric Hollander, two leading researchers in this area, write a review commentary describing a recent paper on oxytocin and "theory of mind" and describe how oxytocin seems to influence both our openness to others and our understanding of them.

The most heavily covered previous oxytocin finding was that an extra dose seemed to make women more trusting -- a report that led to ubiquitous Internet sales pitches of oxytocin as a "date aid." The study reviewed here has the potential for more noble development, since it focuses on the sorts of social understanding and perception that go awry in autism and similar conditions.

Check it out -- and while you're at it, take an online "Mind-Reading" quiz full of eye-interpretation questions like the one shown above.

Adieu to Grace Paley

Grace Paley passed away, at 84, after a long battle with breast cancer. I heard her read once at a tribute to Howard Norman here in Montpelier, and her presence was as lively, funny, and riveting as her stories are. The Times story on her passing sums it up well:

Grace Paley, the celebrated writer and social activist whose short stories explored in precise, pungent and tragicomic style the struggles of ordinary women muddling through everyday lives, died on Wednesday at her home in Thetford Hill, Vt. ...

Ms. Paley’s output was modest, some four dozen stories in three volumes: “The Little Disturbances of Man” (Doubleday, 1959); “Enormous Changes at the Last Minute” (Farrar, Straus & Giroux, 1974); and “Later the Same Day” (Farrar, Straus & Giroux, 1985). But she attracted a devoted following and was widely praised by critics for her pitch-perfect dialogue, which managed at once to be surgically spare and almost unimaginably rich.

Out-of-Body Experiences Enter the Lab

Here's a juicy one from the Aug 24 Science.

Labs in Switzerland and the UK have independently used visual tricks to induce "out-of-body" experiences in healthy lab volunteers. At the UK lab -- the ever-productive Wellcome Trust Centre for Neuroimaging in London -- they seem to have combined some visuo-sensory illusions of the sort pioneered by V.S. Ramachandran with some fancy head-mounted display goggles to fool the person into seeing his or her own body elsewhere -- and then feel it when the phantom body gets tapped.

As Greg Miller's news story in Science puts it

Out-of-body experiences are associated more with tabloid newspapers, New Age Web sites, and large doses of hallucinogenic drugs than serious scientific discussion. Yet they're often reported by reputable people who suffer from migraine headaches, epilepsy, and other neurological conditions. Intrigued by such accounts, some researchers are trying to figure out how the brain creates an aspect of human consciousness so fundamental that we take it for granted: the perception that the 'self' conforms to the borders of the physical body.

Now, two teams of cognitive neuroscientists independently report on pages 1048 and 1096 methods for inducing elements of an out-of-body experience in healthy volunteers. Both groups used head-mounted video displays to give people a different perspective on their own bodies. Each team also drew upon the sense of touch to enhance the illusion. Although details of the experience differed, the people in both experiments reported feelings of dissociation from their bodies. The researchers say their findings will pave the way to new brain-imaging studies of body perception and could have practical applications, such as helping virtual-reality programmers design environments that make users feel as if they are really there.

'It's striking because when you hear about out-of-body experiences, it sounds so deeply weird,' says Chris Frith, a cognitive neuroscientist at University College London who did not participate in the new research. 'These studies show you can actually manipulate it experimentally.' The illusions add to evidence that the brain's representation of the physical body is malleable and can be modified by information from the senses, Frith says.

A 2005 paper from the Swiss lab had speculated that out-of-body experiences, or "OBEs,"

are related to a failure to integrate multisensory information from one’s own body at the temporo-parietal junction (TPJ). It is argued that this multisensory disintegration at the TPJ leads to the disruption of several phenomenological and cognitive aspects of self-processing, causing illusory reduplication, illusory self-location, illusory perspective, and illusory agency that are experienced as an OBE.

H. Henrik Ehrsson's brief UCL report doesn't speculate about the anatomical/functional roots of this illusion; Olaf Blanke's paper does.

This is interesting for many reasons. Among them is that such out-of-body experiences support the idea that we have an identity or "soul" independent of our bodies, which in turn supports the dualist notion that mind and brain are two separate things. Modern neuroscience increasingly insists otherwise. These papers hardly settle the argument. But they do seem to erode one type of anecdotal evidence that a soul or mind or identity arises separately from the body.

Is this a neuroscientific parlor game? Well, no. As earlier essays and papers by Frith and Blanke make clear (e.g., Frith's essay about Blanke's paper on several strange neurological cases , the mechanisms being manipulated here may, when they go awry, contribute to disorders involving everything from face recogntion to movement. Great stuff.

For more, see pieces by Blanke here. And Sandra Blakeslee has a story on the two Science papers in today's New York Times.

Technorati Tags:
medicine, neuroscience, illusions, out-of-body experiences

European heat waves double in length since 1880

A recent study in the American Geophysical Union'sJournal of Geophysical Research-Atmospheres confirms that it really is getting hotter. The study found heat waves in Europe have doubled in length and that extremely hot days are three times as common as a century ago.

From the AGU press release:

The new data shows that many previous assessments of daily summer temperature change underestimated heat wave events in western Europe by approximately 30 percent.

Paul Della-Marta and a team of researchers at the University of Bern in Switzerland compiled evidence from 54 high-quality recording locations from Sweden to Croatia and report that heat waves last an average of 3 days now—with some lasting up to 4.5 days—compared to an average of around 1.5 days in 1880. The results are published 3 August in the Journal of Geophysical Research-Atmospheres, a publication of the American Geophysical Union. The researchers suggest that their conclusions contribute to growing evidence that western Europe’s climate has become more extreme and confirm a previously hypothesized increase in the variance of daily summer temperatures since the 19th century.

The study adds evidence that heat waves, such as the devastating 2003 event in western Europe, are a likely sign of global warming; one that perhaps began as early as the 1950s, when their study showed some of the highest trends in summer mean temperature and summer temperature variance.

“These results add more evidence to the belief among climate scientists that western Europe will experience some of the highest environmental and social impacts of climate change and continue to experience devastating hot summers like the summer of 2003 more frequently in the future,” Della-Marta said.

You can read the whole press release; download the paper (for $9); or check out the rest of Della-Marta's work tracking the history of recent climate change in Europe.

Bird Nannies Give Mom a Break

A splendid -- and to parents and young'n's, painfully relevant -- bit of research news from Science :

Every parent can use a little help now and then, and birds are no exception. Some species even use nannies to feed and care for chicks. These 'daycare' babies don't seem to do any better than offspring raised by mom and dad alone do, however, and researchers have struggled to figure out how birds benefit from the assistance. A new study has cracked the mystery: The nannies apparently allow mother birds to save their strength so they can lay eggs later on.

If you've a Science subscription you can read the news story or t the actual paper. Sans subscription you can still read the abstract or, elsewhere, a web site about the lovely birds in the study, superb fairy-wrens, pictured above -- male at left, female at right.

Image via Wikipedia Commons.