The graphologists analyzed signatures and writing samples from the three candidates -- thank-you notes from Clinton and Obama and book pages inscribed by McCain.
Despite vast policy differences, McCain and Obama have something in common signature-wise -- illegibility, which suggests a need for privacy or an aversion to transparency.
In McCain's case, that desire can be seen further in his H, which is not a loop, but an upward stroke overlapped by a downward one. "There is a lot about John McCain he doesn't wish to share openly," said Roger Rubin, a New York graphologist with three decades of experience.
"When you cover a stroke, it means you are hiding something," Rubin said.
Both men's signatures also reflect a desire to distance themselves from their fathers, the experts said.
Obama was 2 when his father left the family, and McCain's, a respected Navy admiral, was often absent. That shows up in the emphasis they give their first names -- symbols of their personal achievements rather than the legacies to which they were born. Look at the J in John and the B in Barack -- each larger than the M in McCain and the O in Obama.
Clinton's signature is readable, but lacks emotion and warmth -- the two Ls in Hillary are sticks rather than loops. The simplicity shows intellect and forcefulness. Her husband's signature, a bulbous, curvaceous scrawl, is rounder and more feminine. (Hence the gender-reversal thing.)
The body of one's writing can be revealing because, unlike the practiced brand of a signature, it is spontaneous and unconscious. Together they form a psychological snapshot, graphologists say.
Clinton's style is upright and controlled. The I's are dotted and the Ts are crossed. "She can see both sides and would be good at sorting out conflicts," said Sheila Lowe, a Ventura graphologist and author of "Handwriting of the Famous and Infamous."
Clinton reduces things to their simplest form, Rubin said. "She goes easily to the core of a subject. But she can be impolitic and impatient with people who don't get it," he said.
A thank-you note written by Obama after his win in Iowa reflects intelligence, Rubin asserted, but with emotion and a capacity for conversation. The letters connect fluidly without interruption; words end with lines that reach out. "That's why the guy can stand up on a podium and talk extemporaneously. It reflects in his writing -- the ability to think many thoughts ahead," Rubin said.