Washington, Feb 27 (IANS) Since at least the days of Socrates, humans have been advised to "know thyself". And through the years, many social psychologists have believed the individual is the best judge of his or her own personality. But that may not really be the case.

Now a psychologist in Washington University School of Medicine (WUSM) in St. Louis has shown that we are not the 'know-it-alls' that we think we are.

Simine Vazire, WUSM assistant professor of psychology, has found that the individual is more accurate in assessing one's own internal or neurotic traits, such as anxiety.

But personality comprises underlying traits that drive behaviour, Vazire says. And friends are better barometers of intellect-related traits such as intelligence and creativity.

Even strangers are as adept as our friends and ourselves at spotting the extrovert in us all, a psychology domain known as 'extroversion'.

"I think that it's important to really question this knee-jerk reaction that we are our own best experts," says Vazire.

"Personality is not who you think you are, it's who you are. Some people think by definition that we are the experts on our personality because we get to write the story, but personality is not the story - it's the reality," adds Vazire.

Personality, the expert says, is pervasive in many things that we do - clothing choice, bedroom arrangement, website and Facebook profiles for example, says a WUSM release.

"Everything you touch you leave a mark of your personality," she says. "You leave traces unintentionally. You give off hints of your personality that you don't even see yourself."

Vazire's study was published in the February issue of the Journal of Personality and Social Psychology.