Here's a simple arithmetic question: A bat and ball cost a dollar and ten cents. The bat costs a dollar more than the ball. How much does the ball cost?

The vast majority of people respond quickly and confidently, insisting the ball costs ten cents. This answer is both obvious and wrong. (The correct answer is five cents for the ball and a dollar and five cents for the bat.)

For more than five decades, Daniel Kahneman, a Nobel Laureate and professor of psychology at Princeton, has been asking questions like this and analyzing our answers. His disarmingly simple experiments have profoundly changed the way we think about thinking. While philosophers, economists, and social scientists had assumed for centuries that human beings are rational agents - reason was our Promethean gift - Kahneman and his scientific partner, the late Amos Tversky, demonstrated that we're not nearly as rational as we like to believe.

Just a month of meditation training alters brain wiring in ways that could open the door to new treatments for mental disorders, research has shown.

Scientists looked at the effects of integrative body-mind training (IBMT) on two groups of university students.

After just four weeks, or 11 hours, of training scans showed physical changes in the brains of the volunteers.

Nerve fibres, known as 'white matter', became denser, providing greater numbers of brain-signalling connections. At the same time there was an expansion of myelin, the protective fatty insulation surrounding nerve fibres.

The effects were seen in the anterior cingulate cortex region of the brain, which helps regulate behaviour.

Poor nerve activity in this part of the brain is associated with a range of mental problems, including attention deficit disorder, dementia, depression, and schizophrenia.

The study built on previous research based on magnetic resonance imaging (MRI) scans that first highlighted brain changes induced by IBMT. Scientists revisited results from two 2010 studies, taking a closer look at what the scans revealed.

Using MRI scans, researchers have discovered how sleep deprivation can impact the parts of the brain where food-related choices are made, potentially explaining how obesity is linked to a lack of slumber.

The study, which was presented at SLEEP 2012, the 26th annual meeting of the Associated Professional Sleep Societies (APSS), on Sunday, used functional magnetic resonance imaging (fMRI) to study the brain waves of 23 otherwise healthy adults, according to the American Academy of Sleep Medicine.

Subjects were divided into two groups: one of which received a normal night's sleep, and one of which were sleep deprived for an evening. Afterwards, participants in each group rated how much they craved specific food items while inside the fMRI scanner. The study showed that the sleep deprived subjects demonstrated impaired brain activity in their frontal lobe, a region described as "critical" for behavior control and making complex choices, suggesting that sleep loss could adversely impact the food choices that people make.

"Our goal was to see if specific regions of the brain associated with food processing were disrupted by sleep deprivation," lead author Stephanie Greer, a graduate student at the Sleep and Neuroimaging Laboratory at the University of California, Berkeley, said in a statement.

She added that the researchers "did not find significant differences following sleep deprivation in brain areas traditionally associated with basic reward reactivity... Instead, it seems to be about the regions higher up in the brain, specifically within the frontal lobe, failing to integrate all the different signals that help us normally make wise choices about what we should eat."

Research on some of the worst criminals suggests brain chemistry, abnormalities play a part

Can murderously depraved behaviour be biologically based, some glitch or misfiring in the brain that turns people into callous, manipulative and less-than-human monsters?

If the charges against Luka Rocco Magnotta - the Montreal porn actor accused of killing and allegedly eating parts of his victim before sending other body parts through the mail - can be proven, the question for many will be: How could a person be capable of such depravity? And is there any way to detect the psychopaths among us?

Experts say there is no neurological litmus test for psychopathy.

However, over the past decade, there has been a rush to research the brains of society's worst criminals, with a stream of studies linking psychopathic behaviour to physical abnormalities.

When my sons were fighting last week, I had to disarm the five-year-old as he went into battle against his brother - wielding a cricket bat.

Like many parents who've witnessed their children being spiteful or cruel, I felt an icy chill in the stomach. Most parents want their children to be kind and considerate most, if not all, of the time.

But while nearly all youngsters have aggressive moments, for the vast majority - including mine - those moments pass and five minutes later they're demonstrating their sweet, kind natures by giving you a spontaneous hug or sneaking the cat a kitty treat.

For a few unlucky parents, that frightening chill never leaves them. Instead, it grows into a gnawing, aching certainty that something is dreadfully wrong.

One of the more offensive duties of being an investigative journalist is taking out the trash -- exposing liars, fraudsters, con artists and scammers for the people they truly are. Each time we investigate a sociopath, we find that they always have a little cult group following of spellbound worshippers who consider that particular sociopath to be a "guru" or "prophet."

Sociopaths are masters at influence and deception. Very little of what they say actually checks out in terms of facts or reality, but they're extremely skillful at making the things they say sound believable, even if they're just making them up out of thin air. Here, I'm going to present quotes and videos of some legendary sociopaths who convinced everyday people to participate in mass suicides. And then I'm going to demonstrate how and why similar sociopaths are operating right now... today.

Intense and lasting stress may deliver a blow to a kid's noggin, say researchers who found that a brain area linked to memory was smaller in children who had experienced chronic stress compared with their less-strained counterparts.

The brain differences also bore out in cognitive ability, with those children with highly stressful lives performing poorer than other kids on spatial memory tests.

The highly stressed children also had more trouble with tests of short-term memory, including tasks such as finding a token in a series of boxes, the researchers said.

"All families experience some stress, so it is important to note that effects were found for high levels of stress," study researcher Jamie Hanson, a psychology graduate student at the University of Wisconsin-Madison, told LiveScience, adding that some extreme examples would include family members falling victim to violent crimes or the chronic illness of a child or other family member.

The research, detailed in the June 6 issue of the Journal of Neuroscience, adds to other evidence of the impacts of stress, with one recent study showing that children exposed to multiple instances of violence age faster on a cellular level. Another past study suggested childhood stress could actually take years off an individual's life.

A lucky rabbit foot. A glass of wine. A pill. What do these things all have in common? Their effects - whether we do well on a test, whether we mingle at the cocktail party, whether we feel better - all depend on the power of suggestion.

In a new article, psychological scientists Maryanne Garry and Robert Michael of Victoria University of Wellington, along with Irving Kirsch of Harvard Medical School and Plymouth University, delve into the phenomenon of suggestion, exploring the intriguing relationship between suggestion, cognition, and behavior. The article is published in the June issue of Current Directions in Psychological Science, a journal of the Association for Psychological Science.

Over their research careers, Garry and Kirsch have both studied the effects of suggestion on cognition and behavior. Kirsch focused mostly on suggestion in clinical psychology, while Garry, whose work is supported by the Marsden Fund of New Zealand, was interested in the effects of suggestion on human memory. When the two got to talking, "we realized that the effects of suggestion are wider and often more surprising than many people might otherwise think," says Garry.

Women who worry a lot have brains that work overtime even during easy tasks, new research suggests.

The findings could help in the identification and treatment of anxiety disorders, according to the Michigan State University scientists who conducted the study.

"This may help predict the development of anxiety issues later in life for girls," said Jason Moser, a Michigan State psychologist and the lead author of the study. "It's one more piece of the puzzle for us to figure out why women in general have more anxiety disorders."

Women are twice as likely than men to have anxiety disorders. To find out why, Moser and his colleagues used an electrode cap to measure electrical activity in the brain as 79 female college students and 70 male college students completed an easy task.

The volunteers were asked to identify the middle letter in a series of letters. In easy versions, all of the letters were the same ("FFFFF"), and in more difficult versions, the middle letter was different ("EEFEE").

The volunteers also filled out questionnaires about how much they worried.

How to correct for a bias that stop us learning from our mistakes.

Going into business for yourself is scary. Despite all the potential rewards, compared with getting a safe job with a big firm, being an entrepreneur means accepting huge risks.

All entrepreneurs know that there are no guarantees and that new businesses fail at a frighteningly high rate. Still many manage to convince themselves that their venture will be different.

As you might expect, as a group entrepreneurs are remarkably optimistic about their chances of succeeding (otherwise why bother?).