"It's very complex," she says, "because each person has a baseline style of movement. When they're lying, you can see subtle shifts in that."

Bradley took note of Mississippi Sen. Trent Lott's comportment before and after being publicly chastised for praising the pre-civil rights South at a birthday bash for the late Strom Thurmond. The gaffe cost Lott his post as Senate majority leader.

The spring faded from Lott's step with every incremental I-did-nothing wrong denial.

"He literally deflates," Bradley says. "It's almost like the air goes out of him."

Paul Ekman, a California psychologist and professor emeritus at the University of California Medical School in San Francisco, has studied body language for 50 years and works with the State Department and Department of Defense on national security issues. He has identified more than 10,000 facial "microexpressions."

Although he did not see Palmeiro's congressional testimony, Ekman says aggressive behavior such as Palmeiro's is consistent with people who have something to hide.

"Anger is the best mask for any signs of uncertainty or fear," Ekman says. "You could also argue that if he's totally innocent, then he might get angry for being called before Congress."

Ekman is less equivocal regarding Scott Peterson, who was convicted in November of killing his wife, Laci, and their unborn child in 2002.

When Peterson was indicted on murder charges, California detectives asked Ekman to review their initial interviews with him, he says.

'Incongruity'

"I thought it was likely he was lying," Ekman says. "There was enough incongruity between his words spoken, the sound of his voice, the look on his face and his gestures to suggest he was concealing information."

As for Palmeiro, the body of evidence will be the determining factor.

Roger Welsch doesn't like Palmeiro's odds of making it into baseball's Hall of Fame.

Welsch, curator of the tongue--in-cheek National Liar's Hall of Fame in Dannebrog, Neb., saw a clip of Palmeiro's testimony on television and wasn't impressed. "He's probably an amateur liar, but he's a professional ballplayer," Welsch said.

Sun staff writer Rob Hiaasen and researcher Jean Packard contributed to this article.