Tuesday, November 29, 2005

"What's the Buzz? Rowdy Teenagers Don't Want to Hear It"

[C]hildren can hear sounds at higher frequencies than adults can....

The device, called the Mosquito ("It's small and annoying," Mr. Stapleton said), emits a high-frequency pulsing sound that, he says, can be heard by most people younger than 20 and almost no one older than 30. The sound is designed to so irritate young people that after several minutes, they cannot stand it and go away.

So far, the Mosquito has been road-tested in only one place, at the entrance to the Spar convenience store in this town in South Wales. Like birds perched on telephone wires, surly teenagers used to plant themselves on the railings just outside the door, smoking, drinking, shouting rude words at customers and making regular disruptive forays inside.

More @ The New York Times

Wednesday, November 23, 2005

"Mildly depressed people more perceptive than others"

Surprisingly, people with mild depression are actually more tuned into the feelings of others than those who aren’t depressed, a team of Queen’s psychologists has discovered.

“This was quite unexpected because we tend to think that the opposite is true,” says lead researcher Kate Harkness. “For example, people with depression are more likely to have problems in a number of social areas.”

The researchers were so taken aback by the findings, they decided to replicate the study with another group of participants. The second study produced the same results: People with mild symptoms of depression pay more attention to details of their social environment than those who are not depressed....

Previous related research by the Queen’s investigators has been conducted on people diagnosed with clinical depression. In this case, the clinically depressed participants performed much worse on tests of mental state decoding than people who weren’t depressed.

To explain the apparent discrepancy between those with mild and clinical depression, the researchers suggest that becoming mildly depressed (dysphoric) can heighten concern about your surroundings.

More @ Science Blog

"This Is Your Brain Under Hypnosis"

Hypnosis, with its long and checkered history in medicine and entertainment, is receiving some new respect from neuroscientists. Recent brain studies of people who are susceptible to suggestion indicate that when they act on the suggestions their brains show profound changes in how they process information. The suggestions, researchers report, literally change what people see, hear, feel and believe to be true.

The new experiments, which used brain imaging, found that people who were hypnotized "saw" colors where there were none. Others lost the ability to make simple decisions. Some people looked at common English words and thought that they were gibberish.

"The idea that perceptions can be manipulated by expectations" is fundamental to the study of cognition, said Michael I. Posner, an emeritus professor of neuroscience at the University of Oregon and expert on attention. "But now we're really getting at the mechanisms...."

One area that it may have illuminated is the processing of sensory data. Information from the eyes, ears and body is carried to primary sensory regions in the brain. From there, it is carried to so-called higher regions where interpretation occurs.

For example, photons bouncing off a flower first reach the eye, where they are turned into a pattern that is sent to the primary visual cortex. There, the rough shape of the flower is recognized. The pattern is next sent to a higher - in terms of function - region, where color is recognized, and then to a higher region, where the flower's identity is encoded along with other knowledge about the particular bloom.

The same processing stream, from lower to higher regions, exists for sounds, touch and other sensory information. Researchers call this direction of flow feedforward. As raw sensory data is carried to a part of the brain that creates a comprehensible, conscious impression, the data is moving from bottom to top.

Bundles of nerve cells dedicated to each sense carry sensory information. The surprise is the amount of traffic the other way, from top to bottom, called feedback. There are 10 times as many nerve fibers carrying information down as there are carrying it up.

These extensive feedback circuits mean that consciousness, what people see, hear, feel and believe, is based on what neuroscientists call "top down processing." What you see is not always what you get, because what you see depends on a framework built by experience that stands ready to interpret the raw information - as a flower or a hammer or a face.

More @ the New York Times

Monday, November 14, 2005

'When sensation becomes perception'

Perceiving a simple touch may depend as much on memory, attention, and expectation as on the stimulus itself, according to new research from Howard Hughes Medical Institute (HHMI) international research scholar Ranulfo Romo and his colleague Victor de Lafuente. The scientists found that monkeys' perceptions of touch match brain activity in the frontal lobe, an area that assimilates many types of neural information.

Romo and de Lafuente, both of the Institute of Cellular Physiology at the National Autonomous University of Mexico, report their results in the December 2005 issue of the journal Nature Neuroscience, published early online on November 6, 2005.

One of neuroscience's most difficult questions concerns how the brain converts simple sensory inputs to complete perceptual experiences. Many neuroscientists assume that perceptions arise in the sensory cortices, which are the first areas of the brain to process information coming in from sense organs, Romo said. Some recent research, however, has hinted that activity in other parts of the brain may also contribute to sensory perception.

When it comes to the sense of touch, a stimulus at the skin triggers an impulse that travels first to an area at the top of the brain called the primary somatosensory cortex (S1). The information then moves to other parts of the brain, where it can contribute to memory, decision-making, and motor outputs.

To explore what regions of the brain contribute to sensory perception, Romo and de Lafuente analyzed neural activity associated with the sense of touch in macaque monkeys....

The scientists found that activity in S1 neurons, where touch information first arrives, correlated directly with the strength of the stimulus; when the strength of the vibrations was more intense, the S1 neurons' fired more rapidly. However, these neurons' activity did not correlate with the monkeys' behavioral responses. Their firing rates were directly associated with the stimulus intensity, whether the monkeys consciously felt and responded to the stimulus or not.

Romo and de Lafuente also recorded neuronal activity in the medial premotor cortex (MPC), a region of the brain's frontal lobe that is known to be involved in making decisions about sensory information. Activity here did mirror the monkeys' subjective responses to the vibrating probe. MPC neurons responded in an all-or-none manner; they fired when the monkey thought the vibrations were there -- even if they weren't -- and they didn't fire when the monkey thought the vibrations were absent -- even if they were actually occurring.

These results indicate that the monkeys' perceptions arise not from brain activity in the sensory cortex itself, but from activity in the frontal lobe MPC, Romo said....

Romo and de Lafuente also found that MPC neurons began to fire before the stimulus even touched the monkeys' fingertips. Romo believes this is because the monkey is expecting the stimulus and the neurons fire in anticipation.

"I think that we do not feel with our sensory cortices," Romo said. Perceptions instead arise in higher-order brain areas from a combination of sensation, attention, and expectation. "The sensory representation is [just] to confirm something that you have already thought."

More @ Medical News Today

Tuesday, November 08, 2005

"Mystery of 'Blindsight' Lets Some Blind People 'See,' Study Shows"

An innovative research technique is providing insight into why some blind people are able to sense and describe objects they cannot see.

The phenomenon of "blindsight" occurs in some people who suffer injuries to the primary visual cortex, the region of the brain considered essential for sight.

Blindsight allows people to use visual information they get through their eyes even though they have no consciousness of the visual experience, said Christopher Mole, a postdoctoral fellow in philosophy at Washington University in St. Louis, Missouri....

Unconscious Pathway

Blindsight is most prevalent among people who suffer damage to the primary visual cortex, such as in some stroke victims, Mole explained....

"We believe there are pathways that go from the eyes into the brain that bypass the normal routes tied to conscious processing of information."

Ro added that the study supports the theory that these pathways go to a visual center in the brain that is more sophisticated than the visual centers common to all mammals. This suggests the pathways may be unique to higher-order species.

The test results also show that volunteers were more accurate when they were more confident in their guesses.

"It's unclear what that reflects, but what we think it reflects is that this unconscious processing system can contribute to feelings of certainty," Ro said.

In follow-up experiments the team will test why people feel varying levels of confidence in their guesses. Perhaps the unconscious processing routes are stronger in some people than others, Ro said.

More @ National Geographic

"Mark Newbold's Animated Necker Cube"

A slightly different take on the Necker Cube....

:)

"Our Brains Strive to See Only the Good, Leading Some to God"

Life is full of surprises, but it's rare to reach for a carafe of wine and find your hand clutching a bottle of milk -- and even rarer, you'd think, to react by deciding the milk was actually what you wanted all along.

Yet something like that happened when scientists in Sweden asked people to choose which of two women's photos they found most attractive. After the subject made his choice, whom we'll call Beth, the experimenter turned the chosen photo face down. Sliding it across the table, he asked the subject the reasons he chose the photo he did. But the experimenter was a sleight-of-hand artist. A copy of the unchosen photo, "Grizelda," was tucked behind Beth's, so what he actually slid was the duplicate of Grizelda, palming Beth.

Few subjects batted an eye. Looking at the unchosen Grizelda, they smoothly explained why they had chosen her ("She was smiling," "she looks hot"), even though they hadn't....

"Belief in God," says Daniel Gilbert, professor of psychology at Harvard University, "is compelled by the way our brains work."

As shown in the Grizelda-and-Beth study, by scientists at Lund University and published this month in Science, brains have a remarkable talent for reframing suboptimal outcomes to see setbacks in the best possible light. You can see it when high-school seniors decide that colleges that rejected them really weren't much good, come to think of it.

You can see it, too, in experiments where Prof. Gilbert and colleagues told female volunteers they would be working on a task that required them to have a likeable, trustworthy partner. They would get a partner randomly, by blindly choosing one of four folders, each containing a biography of a potential teammate. Unknown to the volunteers, each folder contained the same bio, describing an unlikable, untrustworthy person.

The volunteers were unfazed. Reading the randomly chosen bio, they interpreted even negatives as positives. "She doesn't like people" made them think of her as "exceptionally discerning." And when they read different bios, they concluded their partner was hands-down superior. "Their brains found the most rewarding view of their circumstances," says Prof. Gilbert.

The experimenter then told the volunteer that although she thought she was choosing a folder at random, in fact the experimenter had given her a subliminal message so she would pick the best possible partner. The volunteers later said they believed this lie, agreeing that the subliminal message had led them to the best folder. Having thought themselves into believing they had chosen the best teammate, they needed an explanation for their good fortune and experienced what Prof. Gilbert calls the illusion of external agency.

"People don't know how good they are at finding something desirable in almost any outcome," he says. "So when there is a good outcome, they're surprised, and they conclude that someone else has engineered their fate" -- a lab's subliminal message or, in real life, God.

Religion used to be ascribed to a wish to escape mortality by invoking an afterlife or to feel less alone in the world. Now, some anthropologists and psychologists suspect that religious belief is what Pascal Boyer of Washington University, St. Louis, calls in a 2003 paper "a predictable by-product of ordinary cognitive function."

More @ The Washington Post

Monday, November 07, 2005

Sunday poetry / philosophy / literature blogging (on Monday)

H. L. Mencken's Creed

I believe that religion, generally speaking, has been a curse to mankind - that its modest and greatly overestimated services on the ethical side have been more than overcome by the damage it has done to clear and honest thinking.

I believe that no discovery of fact, however trivial, can be wholly useless to the race, and that no trumpeting of falsehood, however virtuous in intent, can be anything but vicious.

I believe that all government is evil, in that all government must necessarily make war upon liberty...

I believe that the evidence for immortality is no better than the evidence of witches, and deserves no more respect.

I believe in the complete freedom of thought and speech...

I believe in the capacity of man to conquer his world, and to find out what it is made of, and how it is run.

I believe in the reality of progress.

I - But the whole thing, after all, may be put very simply. I believe that it is better to tell the truth than to lie. I believe that it is better to be free than to be a slave. And I believe that it is better to know than be ignorant.

Henry Louis Mencken (1880 - 1956)

Wednesday, November 02, 2005

"Bees Can Solve Complex Color Puzzles, Study Finds"

As they buzz from blossom to blossom, it might seem that bumblebees need to see only flowers, honey, and hive. But a new study suggests that bumblebees have a surprisingly sophisticated visual system.

Through a series of clever experiments, University College London researchers R. Beau Lotto and Martina Wicklein discovered that bees can solve complex color puzzles.

The scientists say the finding may provide new understanding of human vision and guide the development of similar systems for robots. The study appears this week in the Proceedings of the National Academy of Sciences' Online Early Edition.

In bees, as with people, vision has as much to do with the brain as it does with the eye. As Lotto explains, the eye sees by detecting light that falls upon its retina. But, the neuroscientist adds, light that's reflected onto the eye from an object, such as a flower, is constantly changing.

To perceive the flower or anything else, the brain must decipher that light....

So how do the bees pick out the blue flowers amid a kaleidoscope of choices?

"What we've discovered is that the way the bees are solving this problem is that they're using relationships between the flowers," Lotto said. Whether it's within the context of a backlit green array or a backlit yellow array, the bees survey the panel and go for the bluest looking flower.

Dale Purves, director of Duke University's Center for Cognitive Science, said via e-mail that the "highly imaginative" study is important because it shows "that relatively simple invertebrates use the same empirical strategy that humans employ."

"The ability to manipulate the environment of bees in ways that would be impossible in human studies promises many additional insights about the deeper nature of vision across a wide range of animals," he added.

...bees are able to tackle such a complex task and have only a million neurons in their tiny brains....

More @ National Geographic

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

Delusion

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).