Monday, October 31, 2005

"Mirrors can trick the brain into recovering from persistent pain"

Looking in a mirror at a reflection of their healthy hand could help people with persistent pain ease their symptoms and eventually overcome their problem, say scientists in the latest edition of the journal Clinical Medicine.

The treatment, being developed by researchers from the University of Bath and the Royal National Hospital for Rheumatic Diseases (RNHRD), is based on a new theory about how people experience pain even when doctors can find no direct cause.

This ‘cortical’ model of pain suggests that the brain’s image of the body can become faulty, resulting in a mismatch between the brain’s movement control systems and its sensory systems, causing a person to experience pain when they move a particular hand, foot or limb.

Researchers believe that this kind of problem could be behind a host of pain-related disorders, such as complex regional pain syndrome and repetitive strain injury....

“We think it is the same system that is triggered when you are running down stairs, miss the last step and then feel a jolt of surprise.

“In missing that bottom step, you jar the prediction that your brain had made about what was going to happen, triggering an alert to the body that things are not as you expected, hence the feeling of surprise.

“This is because in most cases normal awareness and experience of our limbs is often based on the predicted state rather than the actual state.

“When the two do not match we think sensations are generated to alert the body that things are not as it thought – rather like an early warning mechanism.

“If the discrepancy is very large [like in the mirror experiment described below] then pain may be experienced, as pain is the body’s ultimate warning mechanism....

In a separate study published in the journal Rheumatology earlier this year, researchers from Bath, Cardiff and Exeter showed that it is possible to create sensations and feelings in one limb by looking at a reflection of the other limb in a mirror.

They asked 41 healthy people to sit with a mirror at right angles in front of them so that they could only see one side of their body at a time.

The volunteers were then asked to move their limbs in the same direction at the same time, and then in opposite directions whilst viewing the mirror reflection of one hand.

Within 20 seconds of starting, more than two thirds of people involved in the trial reported some kind of sensation in their hidden limb when the movement they were seeing in the mirror was different to what they were feeling in the hidden hand, for example by moving their hands in different directions.

These sensations included numbness, pins and needles, a change in temperature and moderate aching, despite receiving no neural damage to that limb....

“It would appear that innate susceptibility plays a part, with some individuals more vulnerable to, or simply better at detecting, these sensations.”

More @ the University of Bath


According to the American Psychiatric Association, a delusion is:

'A false belief based on incorrect inference about external reality that is firmly sustained despite what almost everybody else believes and despite what constitutes incontrovertible and obvious proof or evidence to the contrary.'

However, interestingly (and illogically), that false belief is:

'...not one ordinarily accepted by other members of the person's culture or subculture (e.g. it is not an article of religious faith).' [Diagnostic and Statistical Manual of Mental Disorders, IV]

"'Know thyself' - easier said than done"

Benjamin Franklin wrote in his 1750 Poor Richard's Almanac that "There are three things extremely hard: steel, a diamond, and to know one's self." The problem of achieving accurate self-knowledge hasn't gotten any easier in 250 years; and, as shown in a new research report, there are major real-world consequences to this very human attribute.

In "Flawed Self-Evaluation: Implications for Health, Education, and the Workplace," investigators David Dunning (Cornell), Chip Heath (Stanford), and Jerry M. Suls (University of Iowa) summarized current psychological research on the accuracy (or rather inaccuracy) of self-knowledge, across a wide range of studies in a range of spheres. Their report is published in the recent issue of Psychological Science in the Public Interest, a journal of the American Psychological Society....

People generally underestimate their own susceptibility to serious health risks like high blood pressure, cancer, or food poisoning -- partly because they overestimate how different they are from the norm in terms of behaviors that might put them at risk. This can influence the steps people take -- or don't take -- to prevent or treat such problems. On the other side of the health equation, doctors (being people too) overestimate their competence to treat problems outside their areas of specialization.

A similar overconfidence is found in education at all levels. Students and people undergoing professional training show a strong tendency to overestimate their mastery of new knowledge and skills, and teachers and peers are generally much better able than a student is to accurately predict the student's performance on tests....

Although a degree of self-deception may be just part of human nature, individuals aren't completely to blame for their lack of accurate self-knowledge, according to Dunning. There are social and institutional barriers to self-knowledge, such as the difficulty of giving honest critical feedback in workplace settings, as well as to the simple fact that people don't have access to the full range of human competence and skill against which to evaluate their own. Also, in many areas, what people are striving for -- excellence -- is ill-defined.

More @ Medical News Today

From 'Flawed Self-Assessment: Implications for Health, Education, and the Workplace':

People, on average, tend to believe themselves to be above average -- a view that violates the simple tenets of mathematics. In a survey of nearly one million high school seniors, 70% stated that they had "above average" leadership skills, but only 2% felt their leadership skills were "below average." On their ability to get along with others, almost all respondents rated themselves as at least average -- with 60% rating themselves in the top 1% (College Board, 1976-1977). College students think they are more likely than their peers to live past 80 and have a good job; they think they are less likely to acquire a drinking problem or suffer a heart attack (Weinstein, 1980).

Such above-average effects, as they are called, are not constrained to college students. Motorcyclists believe they are less likely to cause an accident than is the typical biker (Rutter, Quine, & Albery, 1998). Business leaders believe their company is more likely to succeed than is the average firm in their industry (Cooper, Woo, & Dunkelberg, 1988; Larwood & Whittaker, 1977). People think they are less susceptible to the flu than their contemporaries, and as a result avoid getting flu shots (Larwood, 1978). Of college professors, 94% say they do above-average work (Cross, 1977). People signing up to bungee jump believe they are more likely to avoid injury than the average bungee jumper, although their friends and family do not share this impression (Middleton, Harris, & Surman, 1996). Ironically, people even state that they are more likely than their peers to provide accurate self-assessments that are uncontaminated by bias (Friedrich, 1996; Pronin, Lin, & Ross, 2002).

Sunday, October 30, 2005

Sunday poetry / philosophy / literature blogging

O sancta simplicitas! In what strange simplification and falsification man lives! One can never cease wondering once one has acquired eyes for this marvel! How we have made everything around us clear and free and easy and simple! how we have been able to give our senses a passport to everything superficial, our thoughts a divine desire for wanton leaps and wrong inferences! how from the beginning we have contrived to retain our ignorance in order to enjoy an almost inconceivable freedom, lack of scruple and caution, heartiness, and gaiety of life -- in order to enjoy life! And only on this now solid, granite foundation of ignorance could knowledge rise so far -- the will to knowledge on the foundation of a far more powerful will: the will to ignorance, to the uncertain, to the untrue! Not as its opposite, but -- as its refinement!

Even if language, here as elsewhere, will not get over its awkwardness, and will continue to talk of opposites where there are only degrees and many subtelties of gradation; even if the inveterate Tartuffery of morals, which now belongs to our unconquerable "flesh and blood," infects the words even of those of us who know better -- here and there we understand it and laugh at the way in which precisely science at its best seeks most to keep us in this simplified, thoroughly artificial, suitably constructed and suitably falsified world -- at the way in which, willy-nilly, it loves error, because, being alive, it loves life.

Nietzsche - 'Beyond Good and Evil' (24)

Thursday, October 27, 2005

"Lying Is Good For You"

Simply put, we lie because it works. When we do it well, we get what we want.

We lie to avoid awkwardness or punishment. We lie to maintain relationships and please others. And, of course, most of all we lie to please ourselves. Whether we’re embellishing our credentials or strengthening our stories, we often tell untruths to make ourselves appear and feel better.

What's more, we lie all the time. In 2002, Robert Feldman, a psychology professor at the University of Massachusetts at Amherst, conducted a study in which he secretly videotaped student’s conversations with strangers. After the fact, he had the students examine the videotapes and identify the untruths. On average, they claim to have told three lies per ten minutes of conversation.

And that number is likely far too low. First, we’re likely to underreport the number of lies we tell (we lie about lying, that is). And Feldman’s study only accounted for lies of the verbal variety, ignoring other deceptive behavior--misleading body language or facial expressions, for example.

In fact, we lie so readily that the dishonesty becomes automatic. Most of the time, we’re not even aware of the lies we tell, explains David Smith, director of the New England Institute at the University of New England and author of Why We Lie. He says we lie best when we don’t know we’re lying. “We don’t have the nervousness or broadcast the tell-tale signs of unease that the intentional liar can barely help,” he explains. “Self-deception is the handmaiden of deceit--in hiding the truth from ourselves, we’re able to hide it more fully from others.”

But why are we so dishonest so often? Isn’t honesty always the best policy? In fact, no. Nobody wants to hear that they look heavier or less attractive. In truth, we consider those who are too honest to be blunt, antisocial and even pathological. A recent study found that adolescents who are most popular with their peers were the ones that were the best at being deceptive.

And lying has proven psychological benefits. For instance, there’s scientific evidence showing that depressive people are more honest with themselves than nondepressive, or mentally healthy, people. When people recover from their depressions, they become less honest....

More @ Forbes ...

... and @ '
The elements of a scientific theory of self-deception' by Robert Trivers

Tuesday, October 25, 2005

"Erotic images can turn you blind"

Researchers have finally found evidence for what good Catholic boys have known all along – erotic images make you go blind. The effect is temporary and lasts just a moment, but the research has added to road-safety campaigners’ calls to ban sexy billboard-advertising near busy roads, in the hope of preventing accidents.

The new study by US psychologists found that people shown erotic or gory images frequently fail to process images they see immediately afterwards. And the researchers say some personality types appear to be affected more than others by the phenomenon, known as “emotion-induced blindness”.

David Zald, from Vanderbilt University in Nashville, Tennessee, and Marvin Chun and colleagues from Yale University in Connecticut, showed hundreds of images to volunteers and asked them to pick a specific image from the rapid sequence. Most of the images were landscape or architectural scenes, but the psychologists included a few emotionally charged images, portraying violent or sexually provocative scenes.

The closer these emotionally charged images occurred prior to the target image, the more frequently people failed to spot the target image, the researchers found.

“We observed that people failed to detect visual images that appeared one-fifth of a second after emotional images, whereas they can detect those images with little problem after neutral images,” Zald says....

And some people are more vulnerable than others. The study assessed participants using a personality questionnaire, rating them according to their level of “harm avoidance”. Those scoring highly were more fearful, careful and cautious; those scoring low were more carefree and more comfortable in difficult or dangerous situations.

The researchers found that those with low harm avoidance scores were better able to stay focused on a target image than those with high harm avoidance scores.

“People who are more harm avoidant may not be detecting negative stimuli more than other people, but they have a greater difficulty suppressing that information,” Zald suggests.

More @ New Scientist

"Color perception: Not in beholder's eye"

ROCHESTER, N.Y., Oct. 25 (UPI) -- University of Rochester scientists say the first images of living human retinas have shown color perception differs dramatically among people.

The researchers found the number of color-sensitive cones in the human retina differs by up to 40 times among people, yet all people appear to perceive colors the same way.

The findings strongly suggest our perception of color is controlled much more by our brains than by our eyes....

"We've shown that color perception goes far beyond the hardware of the eye, and that leads to a lot of interesting questions about how and why we perceive color," he added.

More @ Science Daily

Monday, October 24, 2005

"Brain ‘buffer’ may control premenstrual moods"

An emotional buffer zone in the brain may not be working as it should in women who experience premenstrual moodiness, a new study suggests.

David Silbersweig and colleagues at the Weill Medical College of Cornell University, New York, US, used functional magnetic resonance imaging to scan the brains of 12 women whose moods remained steady throughout their menstrual cycles.

From 1 to 5 days before menstruation, and 8 to 12 days after, the women’s brains were scanned as they were shown printed words with either negative, neutral, or positive connotations – words like “rape”, “cancer”, “bookcase”, “rotate”, “gentle” and “delighted” – to engage the emotion-processing part of the brain.

At the same time, the women were motivated to complete a simple cognitive task. The scans showed that the orbitofrontal cortex – part of the brain involved in controlling emotions and regulating motivation – was more active during the task in the days before menstruation. After menstruation, that part of the brain was relatively inactive during the task.

Silbersweig says that the difference in brain activity may “buffer” hormonal changes in these women, helping them to maintain a consistent emotional state. “Because this area is kicking in, these women are able to avoid moodiness,” he says.

More @ New Scientist ...

... and 'Orbitofrontal cortex activity related to emotional processing changes across the menstrual cycle' in PNAS

"Schizophrenia: Delusion without illusion"

LONDON, Oct. 24 (UPI) -- British scientists say schizophrenics aren't fooled by a visual illusion and can judge it more accurately than can non-schizophrenic observers.

The study by University College London and King's College London researchers suggests in everyday life, schizophrenics take less account of visual context. If this is part of a more general failure to deal appropriately with context, it could explain why some sufferers misattribute people's actions or feel persecuted.

The researchers used an illusion in which an object's contrast appears reduced by its surroundings. A medium-contrast patterned disc was shown to volunteers, who had to judge its appearance in the presence of a high-contrast background. Of 15 participants with chronic schizophrenia, 12 were found to make more accurate judgments than the most accurate person in a control group of 33 non-schizophrenic volunteers.

Dr Steven Dakin of the UCL Institute of Ophthalmology says: "We often think of people with schizophrenia as not seeing the world the way it really is -- for example, during hallucinations -- but we have shown that sometimes their vision can be more accurate than non-sufferers."

From Science Daily

More @ 'Weak suppression of visual context in chronic schizophrenia' in Current Biology

Sunday, October 23, 2005

Sunday poetry / philosophy / literature blogging

MUCH madness is divinest sense
To a discerning eye;
Much sense the starkest madness.
’T is the majority
In this, as all, prevails.
Assent, and you are sane;
Demur,—you ’re straightway dangerous,
And handled with a chain.

Emily Dickinson

Saturday, October 22, 2005

"Humans are governed by emotions -- literally"

The emotional responses that guide much of human behavior have a tremendous impact on public policy and international affairs, prompting government officials to make decisions in response to a crisis -- such as the Sept. 11 terrorist attacks -- with little regard to the long-term consequences, according to a study by scholars at Carnegie Mellon University and the University of Pittsburgh School of Law. The paper, which appears in the Chicago-Kent Law Review, was written by Jules Lobel, a Pitt professor of law, and George Loewenstein, professor of economics and psychology at Carnegie Mellon....

The authors draw on recent research that demonstrates that human decision-making is governed by two neural systems -- the deliberative and the affective, or emotional. The latter, which the authors dub emote control, is much older, and served an adaptive role in early humans by helping them meet basic needs and identify and respond quickly to danger. As humans evolved, however, they developed the ability to consider the long-term consequences of their behavior and to weigh the costs and benefits of their choices. The deliberative system appears to be located in the brain's prefrontal cortex, which grew on top of but did not replace older brain systems.

"Human behavior is not under the sole control of emotion or deliberation but results from the interaction of these two processes," Loewenstein said.

Emote control is fast, but can respond only to a limited amount of situations, while deliberation is far more flexible but relatively slow and laborious. Emote control is the default decision-making system. Deliberation kicks in when a person encounters a situation that is new or when the correct response is not evident. Emote control is highly attuned to vivid imagery, immediacy and novelty, meaning that the emotional system is more likely to respond to events that are associated with striking visual images, that occurred in the recent past, and that people are unfamiliar with and have not had time to adapt to. Emotion also is sensitive to the categories into which humans automatically place the people and things they encounter -- from the perspective of law and social policy, the all-important distinction between "us" and "them." And emote control can activate deliberation, according to Loewenstein and Lobel.

"Moderate levels of fear, anger or any almost any form of negative emotion warn the deliberative system that something is wrong and that its capabilities are required. Perversely, as emotion intensifies, however, it tends to assume control over behavior even as it triggers the deliberative system, so one may realize what the best course of action is, but find one's self doing the opposite," Loewenstein said....

Lobel and Loewenstein do not, of course, suggest that emotions are always bad.... Yet political leaders can exploit emotions for their own ends, so as a society, we must recognize the havoc that emotions can play on public policy....

More @ Science Blog ...

... and 'Emote Control: The substitution of symbol for substance in foreign policy and international law' in the Chicago-Kent Law Review

"Where the brain combines what's heard and felt"

Using functional magnetic resonance imaging, researchers at the Max Planck Institute for Biological Cybernetics in Tübingen, Germany have showed that the integration of auditory and touch information takes place in the 'hearing centre' of the brain - the auditory cortex - and thus at an earlier point than has traditionally been assumed.

Everyday, the brain accesses information from various sense organs simultaneously to create a "picture" of its environment. This important mixture of information from various sense organs is known as "multisensory integration"....

One important question in neuro-research is where multisensory integration takes place. Traditionally, it has been assumed that it doesn't take place in the sensory areas, where the information from sense organs comes in, but rather in a downstream, 'higher' area of the brain known as the 'association cortex'. The information from sense organs - in other words, what is taken in - was considered to be first processed in specific sensory areas; for example, the auditory information from the cochlea in the auditory cortex. Only then, it was assumed, it was integrated with similarly prepared information from visual and tactile impressions.

But new findings, including those of the Max Planck researchers, have showed that this description is not exactly correct. Multimodal integration does indeed take place at deeper levels. Using functional magnetic resonance imaging, the scientists from Tübingen measured the activity of brain cells in the auditory cortex of primates. The anatomical partitioning of the primary and secondary auditory cortexes is known in detail and the scientists can take advantage of the high spatial resolution offered by their approach. This is important because the areas under investigation are smaller than two or three millimeters.

The results clearly show that the activity in the auditory cortex by an auditory impulse is strengthened when it is combined with tactile stimulation of a hand. Furthermore, the researchers found areas inside the auditory cortex that react more strongly to simultaneous impulses than to single stimuli - this is a classic criterion for the identification of multimodal integration. The researchers also showed that this integration takes place in the secondary auditory cortex.

More @ Medical News Today ...

... and 'Integration of Touch and Sound in Auditory Cortex' in Neuron

Friday, October 21, 2005

"Brain Becomes an iPod"

On musical hallucinations:

[Dr. Aziz's] study also shows that these hallucinations are different from the auditory hallucinations of people with schizophrenia. Such people often hear inner voices. Patients like Mr. King hear only music.

The results support recent work by neuroscientists indicating that our brains use special networks of neurons to perceive music. When sounds first enter the brain, they activate a region near the ears called the primary auditory cortex that starts processing sounds at their most basic level. The auditory cortex then passes on signals of its own to other regions, which can recognize more complex features of music, like rhythm, key changes and melody.

Neuroscientists have been able to identify some of these regions with brain scans, and to compare the way people respond to musical and nonmusical sounds.

Dr. Tim Griffiths, a neurologist at the University of Newcastle Upon Tyne in England, performed one of these studies on six elderly patients who developed musical hallucinations after becoming partly deaf....

Dr. Griffiths discovered a network of regions in the brain that became more active as the hallucinations became more intense. "What strikes me is that you see a very similar pattern in normal people who are listening to music," he said.

The main difference is that musical hallucinations don't activate the primary auditory cortex, the first stop for sound in the brain. When Dr. Griffith's subjects hallucinated, they used only the parts of the brain that are responsible for turning simple sounds into complex music.

These music-processing regions may be continually looking for signals in the brain that they can interpret, Dr. Griffiths suggested. When no sound is coming from the ears, the brain may still generate occasional, random impulses that the music-processing regions interpret as sound. They then try to match these impulses to memories of music, turning a few notes into a familiar melody.

More @ The New York Times ...

... and, 'An iPod in Your Head' @ The Loom

"Checkershadow Illusion"

The squares marked A and B are the same shade of gray, yet they appear different. By joining the squares marked A and B with two vertical stripes of the same shade of gray, it becomes apparent that both squares are the same....

The visual system is not very good at being a physical light meter, but that is not its purpose. The important task is to break the image information down into meaningful components, and thereby perceive the nature of the objects in view.

More proof @ Edward H. Adelson's Checkershadow Illusion page.

"Why do we believe in God?"

Thomas Bouchard, professor of psychology at the University of Minnesota, recognized that these twins [separated at birth and adopted by different families], if compared with each other as they grew up, would provide an important way of measuring genetic and environmental influences....

In one study, Bouchard concentrated on72 sets of twins who had reached adulthood. He first established which of the twins (35 sets in all) were genuinely identical by genetic testing.

These were then invited to complete personality tests.

Such questionnaires, which are widely used by psychologists, pose questions in the form of statements, to which the respondents have to rate their level of agreement on a scale of one to eight. The following is a small sample of the many statements relating to religion:

· I enjoy reading about my religion.
· My religion is important to me because it answers many questions about the meaning of life....

When Bouchard and his team compared the answers to these and other personality questions, they found strong statistical evidence that identical and non-identical twins tended to answer differently. If one identical twin showed evidence of religious thinking or behaviour, it was much more likely that his or her twin would answer similarly.

Non-identical twins, as might be expected (they are, after all, related), showed some similarities of thinking, but not nearly to the same degree. Crucially, the degree of religiosity was not strongly related to the environment in which the twin was brought up. Even if one identical twin had been brought up in an atheist family and the other in a religious Catholic household, they would still tend to show the same kind of religious feelings, or lack of them.

More @
The Guardian

'Genetic and environmental influences on human psychological differences'

"What Other People Say May Change What You See"

A new study uses advanced brain-scanning technology to cast light on a topic that psychologists have puzzled over for more than half a century: social conformity....

The researchers found that social conformity showed up in the brain as activity in regions that are entirely devoted to perception. But independence of judgment - standing up for one's beliefs - showed up as activity in brain areas involved in emotion, the study found, suggesting that there is a cost for going against the group.

"We like to think that seeing is believing," said Dr. Gregory Berns, a psychiatrist and neuroscientist at Emory University in Atlanta who led the study.

But the study's findings, he said, show that seeing is believing what the group tells you to believe.

More @ The New York Times

'Neurobiological Correlates of Social Conformity and Independence During Mental Rotation'

"See No Bias"

At 4 o'clock on a recent Wednesday afternoon, a 34-year-old white woman sat down in her Washington office to take a psychological test. Her office decor attested to her passion for civil rights -- as a senior activist at a national gay rights organization, and as a lesbian herself, fighting bias and discrimination is what gets her out of bed every morning. A rainbow flag rested in a mug on her desk.

The woman brought up a test on her computer from a Harvard University Web site. It was really very simple: All it asked her to do was distinguish between a series of black and white faces. When she saw a black face she was to hit a key on the left, when she saw a white face she was to hit a key on the right. Next, she was asked to distinguish between a series of positive and negative words. Words such as "glorious" and "wonderful" required a left key, words such as "nasty" and "awful" required a right key. The test remained simple when two categories were combined: The activist hit the left key if she saw either a white face or a positive word, and hit the right key if she saw either a black face or a negative word.

Then the groupings were reversed. The woman's index fingers hovered over her keyboard. The test now required her to group black faces with positive words, and white faces with negative words. She leaned forward intently. She made no mistakes, but it took her longer to correctly sort the words and images.

Her result appeared on the screen, and the activist became very silent. The test found she had a bias for whites over blacks.

"It surprises me I have any preferences at all," she said. "By the work I do, by my education, my background. I'm progressive, and I think I have no bias. Being a minority myself, I don't feel I should or would have biases."

Although the activist had initially agreed to be identified, she and a male colleague who volunteered to take the tests requested anonymity after seeing their results. The man, who also is gay, did not show a race bias. But a second test found that both activists held biases against homosexuals -- they more quickly associated words such as "humiliate" and "painful" with gays and words such as "beautiful" and "glorious" with heterosexuals....

"I'm surprised," the woman said. She bit her lip. "And disappointed...."

More @ The Washington Post

Implicit Association Tests