People have created various ways to classify personality, or temperament, and it's interesting that many of them choose four general traits as their basis.

Examples:

Keirsey's Four Temperaments uses the following:

• Rationals

• Idealists
• Artisans
• Guardians

• introversion/extroversion

If you walk into the office of a scientist, chances are you'll see a white board hanging on the wall covered in scrawls. A molecular biologist's white board might be covered by hideous tangles of protein chains. A geophysicist might doodle India crashing into southern Asia.

The scribbles of Dr. Michael Gazzaniga, the director of the Center for Cognitive Neuroscience at Dartmouth, are more metaphysical. Arrows travel from a pair of eyes into a cartoon brain, finally ending at the word "Apple." Another picture bluntly sums up the modern debate over free will, with a stick figure's head labeled "Brain," and two bubbles point toward it - one labeled "Judge" and the other "Neu" - short for neuroscience. Floating uncertainly off to one side is a third bubble that asks, "Mind?"

Big questions are Dr. Gazzaniga's stock in trade. In the 1980's he helped found cognitive neuroscience, a discipline designed to find out how the mind emerges from the brain. Today, at age 65, he continues to oversee a busy lab where brain scans offer clues to how we unconsciously create theories to explain the outer world and our inner lives.

Last July, Steven Miller, a university librarian, came across an article about a set of neurological conditions he had never heard of called autistic spectrum disorders. By the time he finished reading, his face was wet with tears.

"This is me," Mr. Miller remembers thinking in the minutes and months of eager research that followed. "To read about it and feel that I'm not the only one, that maybe it's O.K., maybe it's just a human difference, was extremely emotional. In a way it has changed everything, even though nothing has changed."

Mr. Miller, 49, who excels at his job but finds the art of small talk impossible to master, has since been given a diagnosis of Asperger's syndrome, an autistic disorder notable for the often vast discrepancy between the intellectual and social abilities of those who have it.

How you react to stress influences how easily you resist or succumb to disease, including viruses like HIV, discovered UCLA AIDS Institute scientists. Reported in the Dec.15 edition of Biological Psychiatry, the new findings identify the immune mechanism that makes shy people more susceptible to infection than outgoing people.

Buddhists who meditate may be able to train their brains to feel genuine happiness and control aggressive instincts, research has shown.

According to Owen Flanagan, professor of philosophy at Duke University in North Carolina, Buddhists appear to be able to stimulate the left prefrontal lobe - an area just behind the forehead - which may be why they can generate positive emotions and a feeling of well being.

Studies of a gene that affects how efficiently the brain's frontal lobes process information are revealing some untidy consequences of a tiny variation in its molecular structure and how it may increase susceptibility to schizophrenia. People with a common version of the gene associated with more efficient working memory and frontal lobe information processing may pay a penalty in adverse responses to amphetamine, in heightened anxiety and sensitivity to pain. Yet, another common version may slightly bias the brain toward a pattern of neurochemical activity associated with psychosis, report researchers at the National Institutes of Health (NIH).

Do you know someone who needs hours alone every day? Who loves quiet conversations about feelings or ideas, and can give a dynamite presentation to a big audience, but seems awkward in groups and maladroit at small talk? Who has to be dragged to parties and then needs the rest of the day to recuperate? Who growls or scowls or grunts or winces when accosted with pleasantries by people who are just trying to be nice?

If so, do you tell this person he is "too serious," or ask if he is okay? Regard him as aloof, arrogant, rude? Redouble your efforts to draw him out?

If you answered yes to these questions, chances are that you have an introvert on your hands—and that you aren't caring for him properly. Science has learned a good deal in recent years about the habits and requirements of introverts. It has even learned, by means of brain scans, that introverts process information differently from other people (I am not making this up). If you are behind the curve on this important matter, be reassured that you are not alone. Introverts may be common, but they are also among the most misunderstood and aggrieved groups in America, possibly the world.

Not only are selves conditional but they die. Each day we wake slightly altered and the person we were yesterday is dead.
- John Updike

From kissing frogs to demonic possession, people are led to believe they experienced the improbable.

During a recent study of memory recall and the use of suggestive interviewing, UC Irvine cognitive psychologist Elizabeth Loftus successfully planted false memories in volunteers of several study groups -- memories that included such unlikely events as kissing frogs, shaking hands with Bugs Bunny at Disneyland, and witnessing a demonic possession.

Frightening new evidence of the brain's susceptibility to suggestion was presented on Sunday to the American Association for the Advancement of Science.

Psychologists described recent experiments in which they implanted false memories, altered perceptions through subliminal messages, and demonstrated the intense emotional distress of people who believed they had been abducted by aliens.

The researchers said their work showed that courts, police and other agencies needed to be extremely wary of relying solely on the memory of witnesses - for example in sex abuse cases - because even the most intense memories could be false.

Science is developing ways to boost intelligence, expand memory, and more. But will you be allowed to change your own mind?

"We're on the verge of profound changes in our ability to manipulate the brain," says Paul Root Wolpe, a bioethicist at the University of Pennsylvania. He isn't kidding. The dawning age of neuroscience promises not just new treatments for Alzheimer's and other brain diseases but enhancements to improve memory, boost intellectual acumen, and fine-tune our emotional responses. "The next two decades will be the golden age of neuroscience," declares Jonathan Moreno, a bioethicist at the University of Virginia. "We're on the threshold of the kind of rapid growth of information in neuroscience that was true of genetics 15 years ago."

The Blank Slate: The Modern Denial of Human Nature
Copyright 2002

By Steven Pinker

Examples and discussion of peer pressure.

advertising, fads, body piercing, "keeping up with the joneses", risk taking...

Evolutionary ties
Military benefits

Never try to teach a pig to sing. It wastes your time, and it annoys the pig.
- Paul Dickson

Every man, wherever he goes, is encompassed by a cloud of comforting convictions which move with him like flies on a summer day.
- Bertrand Russell