Overprecision -- excessive confidence in the accuracy of our beliefs -- can have profound consequences, inflating investors' valuation of their investments, leading physicians to gravitate too quickly to a diagnosis, even making people intolerant of dissenting views. Now, new research confirms that overprecision is a common and robust form of overconfidence driven, at least in part, by excessive certainty in the accuracy of our judgments.

The research, conducted by researchers Albert Mannes of The Wharton School of the University of Pennsylvania and Don Moore of the Haas School of Business at the University of California, Berkeley, revealed that the more confident participants were about their estimates of an uncertain quantity, the less they adjusted their estimates in response to feedback about their accuracy and to the costs of being wrong.

"The findings suggest that people are too confident in what they know and underestimate what they don't know," says Mannes.

The new findings are published in Psychological Science, a journal of the Association for Psychological Science.

Research investigating overprecision typically involves asking people to come up with a 90% confidence interval around a numerical estimate -- such as the length of the Nile River -- but this doesn't always faithfully reflect the judgments we have to make in everyday life. We know, for example, that arriving 15 minutes late for a business meeting is not the same as arriving 15 minutes early, and that we ought to err on the side of arriving early.

Mannes and Moore designed three studies to account for the asymmetric nature of many everyday judgments. Participants estimated the local high temperature on randomly selected days and their accuracy was rewarded in the form of lottery tickets toward a prize. For some trials, they earned tickets if their estimates were correct or close to the actual temperature (above or below); in other trials, they earned tickets for correct guesses or overestimates; and in some trials they earned tickets for correct guesses or underestimates.

The results showed that participants adjusted their estimates in the direction of the anticipated payoff after receiving feedback about their accuracy, just as Mannes and Moore expected.

Nothing, some say, turns an atheist into a believer like the fear of death. "There are no atheists in foxholes," the saying goes. But a new study suggests that people in stressful situations don't always turn to a higher power. Sometimes, they turn to science.

For the new work, researchers stayed away from foxholes. Instead, they focused on another stressful - yet significantly less dire - activity: competitive rowing. The scientists recruited 100 rowers mostly in their 20s who lacked strong religious commitments, as determined by a questionnaire.

The scientists broke the athletes into two groups. One was about to race in a regatta; the other was preparing for a less stressful training session. Both groups were asked whether they agreed with statements such as: "We can only rationally believe in what is scientifically provable," "All the tasks human beings face are soluble by science," and "The scientific method is the only reliable path to knowledge."

Not surprisingly, the athletes who were getting ready to compete reported higher anxiety levels. They were also about 15% more likely to express a strong belief in science than their less stressed colleagues, a statistically significant difference.

Some doctors balk at the idea of trying to change a patient's personality, but a new study suggests that they're doing it already.

The results show that talk therapy or psychiatric medications can change personality in healthy people and those with psychological disorders. What's more, changes can be relativity rapid, occurring over a four- to seven-month period, and long-lasting, continuing years after therapy, according to the study.

Most mental health professionals don't think about psychiatric treatments as a means of changing personality - they view treatments as a way to change behavior, said study researcher Brent Roberts, a professor of psychology at the University of Illinois at Urbana-Champaign.

The findings are provocative, the researchers say, because for a long time, psychologists thought personality traits were static. While some recent research suggests that personality traits can change over time, most had assumed this change was difficult and incremental - not a quick process.

A lot of people get upset by the idea of changing personality because "they feel like you're screwing with somebody's intrinsic nature," Roberts said. But, "We're already change [patient's] personality traits, whether we like it or not."

The findings present a new way of looking at how psychiatric therapies work, and raise the question of whether interventions should more directly target personality. Personality traits affect many different areas of life - including relationships, and school and work success - although their consequences often go unnoticed, Roberts said.

"We know that people who are less anxious and more conscientiousness do better in school and the labor market," Roberts said. Perhaps by doing an intervention on young people, to make them more conscientiousness, "you may make them more successful in their jobs at 40," he said.

There is no way around it. Nearly two decades of research on yoga has conclusively established that yoga not only improves physical fitness, overall health, and mental and emotional well-being, it is a healing modality par excellence.

In his comprehensive book, Yoga as Medicine, Timothy McCall, MD. discusses the evidence for the therapeutic value of yoga in many conditions including: alcoholism, anxiety and stress, asthma, ADHD, cancer, carpel tunnel syndrome, chronic obstructive pulmonary disorder, congestive heart failure, depression, diabetes, eating disorders, fibromyalgia, high blood pressure, infertility, insomnia, IBS, migraines, MS, neurological and neuromuscular diseases, osteoporosis, pain, rheumatoid arthritis, scoliosis, urinary stress incontinence...and the list goes on.

Study after study shows yoga can help virtually every ailment under the sun - not to mention its amazing rejuvenating and anti-aging properties. (See links below) Moreover, a great deal of research also shows that these same healing benefits do not accrue from just doing regular exercise.

So why is yoga different?

The brain's internal clock keeps time via a synchronized network of cells that is able to reset itself, a new study reveals.

This resetting may be what enables us to change our own daily rhythms with the seasons while the clock itself remains fairly stable, the researchers report.

But this mechanism didn't evolve to deal with modern technologies, such as alarm clocks or air travel. Messing with natural daily cycles can cause jetlag, or more serious effects. Shift work, for instance, has been linked to metabolic disorders such as diabetes, and even diseases like cancer.

"Shift work is now listed as a potential carcinogen by the World Health Organization," said study researcher Erik Herzog, a biologist at Washington University in St. Louis. By understanding how the brain's clock is wired, researchers could develop ways to improve the brain's ability to deal with these kinds of environmental perturbations, so they have fewer detrimental effects on our health, Herzog told LiveScience.

The brain's timing center is called the suprachiasmatic nucleus, or SCN. "Each cell is its own little timer," which works by turning on and off a set of "clock genes" that tell the cell to make proteins, Herzog explained. These genes operate on an approximately 24-hour cycle, known as a circadian rhythm. These cycles are important for regulating metabolism, hormone release and sleep/waking cycles.

Is humanity getting smarter or dumber with time? The answer may be both.

While IQ scores are rising at a remarkable rate, humans' underlying genetic potential for smarts could be on the decline, a new study suggests. The research found that by one measure of intelligence, the Victorians had modern folk beat.

The findings aren't without controversy - particularly whether or not the measurements used really reveal intelligence. Still, the study highlights the trouble with measuring intelligence over time: Smarts aren't defined as just one thing. What makes a person clever on the African Savannah could be nearly useless in the financial centers of Hong Kong.

"It's not simply that intelligence is going down or going up," said Michael Woodley, a psychologist at Umea University in Sweden who led the new research. "Different parts of intelligence could be changing in lots of different ways."

When Frank Parsons opened the world's first career guidance center in Boston in 1908, he began by asking prospective clients 116 penetrating questions about their ambitions, strengths, and weaknesses (and how often they bathed). But then he did something more unusual: He measured their skulls.

Parsons was a committed believer in phrenology. If you had a large forehead, he might recommend you become a lawyer or engineer. But if your skull was more developed behind the ears, you were of the "animal type" and best suited to manual work.

Career advice has, thankfully, come a long way since then. But now, instead of measuring the outside of people's heads, it has become common to measure the inside using psychometric tests. Personality testing has grown into a major industry and is standard procedure in leadership and management courses, as part of job-interview processes, and, increasingly, in career counselling. But should we really trust such tests to deliver scientific, objective truth?

I have some bad news for you: Even the most sophisticated tests have considerable flaws. Take the Myers-Briggs Type Indicator (MBTI), the world's most popular psychometric test, which is based on Jung's theory of personality types. Over two million are administered every year. The MBTI places you in one of 16 personality types, based on dichotomous categories such as whether you are an introvert or an extrovert, or have a disposition towards being logical or emotional (what it calls "thinking" and "feeling").

For centuries, the art of breathing has been one of a myriad of tools employed by Yoga masters in order to calm the body and mind, in preparation for meditation, contemplation or simply to remain in control of one's emotions. Long utilized as a spiritual practice, a recent study has now brought the use of breathing as a way to control emotions into the realm of neuroscience. The results are promising and could mean a reduction in the administration of drugs as a form of anxiety, depression and anger management.

The study and its findings

Carried out at the Universite de Louvain by Dr. Pierre Philippot, the research study focused on two groups with the aim of investigating whether breathing can generate and regulate emotions and their intensity.

Sarah dreads falling asleep. Moments after she closes her eyes, her body becomes paralysed, and she is unable to move no matter how hard she tries.

This has been going on almost every night for three weeks.

Sarah has also noticed a dark, ghostly figure standing over her bed from time to time, which seems to be the cause of the paralysis. It's a frightening, agonising experience.

Sarah is experiencing a phenomenon called sleep paralysis. Although the condition primarily involves a sense of not being able to move prior to falling asleep, it can also include vivid hallucinations and visions. Sometimes people see a ghost or sense a negative presence in the room during an episode. Others report sleep paralysis as a form of alien abduction or other paranormal activity.

Although Sarah reported disturbing hallucinations, she has not been diagnosed with a mental illness. This is not uncommon in accounts of the paranormal; many have a logical explanation, such as perceptual error. In fact, some researchers estimate only half of paranormal or mystical experiences - such as out-of-body experiences, telepathy, intuition and precognition - are associated with a mental disorder.

Paranormal experiences may be very distressing, so it's important people have the opportunity to talk about them. Yet, many psychotherapists and psychiatrists lack adequate training and skills to deal with accounts of the paranormal.

Women at a particular stage in their monthly menstrual cycle may be more vulnerable to some of the psychological side-effects associated with stressful experiences, according to a study from UCL.

The results suggest a monthly window of opportunity that could potentially be targeted in efforts to prevent common mental health problems developing in women. The research is the first to show a potential link between psychological vulnerability and the timing of a biological cycle, in this case ovulation.

A common symptom of mood and anxiety problems is the tendency to experience repetitive and unwanted thoughts. These 'intrusive thoughts' often occur in the days and weeks after a stressful experience.

In this study, the researchers examined whether the effects of a stressful event are linked to different stages of the menstrual cycle. The participants were 41 women aged between 18 and 35 who had regular menstrual cycles and were not using the pill as a form of contraception. Each woman watched a 14-minute stressful film containing death or injury and provided a saliva sample so that hormone levels could be assessed. They were then asked to record instances of unwanted thoughts about the video over the following days.