Rafael Palmeiro sent up an unmistakable red flag about steroid use on March 17, at least in the mind of John Boe, a California body-language expert.

That's when the Orioles first baseman testified before a congressional committee and denied ever using steroids. He punctuated his remarks with a few awkward jabs of his index finger, as if angrily ringing an invisible doorbell.

Palmeiro might as well have mimicked shooting himself in the foot, Boe says.

"That finger thing, in body-language terms, that's taking a baton and beating people over the head with it and telling them to back off," says Boe, who has analyzed about 10,000 personality profiles and writes frequently about body language. "It's aggressive. ... It's a red flag."

Having since tested positive for steroids, Palmeiro is serving a 10-day suspension from baseball and facing a congressional investigation.

He has also joined a long list of public figures who memorably protested their innocence, only to be later haunted by their own words and gestures.

Boe and others say body language often gives them away.

Think of Richard Nixon, of the famously sweaty upper lip, clutching that presidential lectern with two hands during his Watergate-era news conferences.

Think of Bill Clinton and his finger-pointing denials about having had a sexual relationship with Monica Lewinsky.

Think of Pete Rose and his jut-jawed refusals to acknowledge betting on baseball (later retracted).

Nonverbal clues

Police and prosecutors use such nonverbal cues - the jutting jaws and finger-pointing - to evaluate the credibility of witnesses. At the FBI academy, recruits study body language as part of interviewing strategy. And parents know that children's actions often speak louder than seemingly innocent words.

The telltale signs of fudging and fabrication include shifting eyes and shuffling feet, the wrinkled nose, a hand inadvertently covering the mouth - as if filtering the truth - a crossing of arms or legs.

The question is how much emphasis should be put on body language as a window to the soul.

Boe puts more faith in how people move and less in what they say.

"If there's a disconnect between the verbal and nonverbal," he says, "take the nonverbal as being more accurate."

For that reason, Boe was less impressed with Palmeiro's defiant congressional testimony than with fellow ballplayer Mark McGwire's stonewalling about steroid use during the same inquiry.

"His [Palmeiro's] gestures were too strong for the situation," says Boe. "I have respect for McGwire. They both were tainted, but at least one was honest. ... McGwire's demeanor was very calm."

Karen Kohn Bradley, a visiting professor of dance at the University of Maryland, College Park who specializes in movement analysis, has studied politicians' movements and gestures for about 30 years. Truth often speaks louder through body language, she says, although it's more a whisper than a scream.