Facial features offering clues about a person's sex, age, emotions and intentions helped early humans "know whether the guy that just stepped out of the bushes is going to take your head back for a trophy or invite you to lunch," Slice said.

Those identifications are so important that people also tend to see faces even where they don't exist.

"If you get it wrong and you see a face in a cloud or a stone or a mountain or some burnt toast then you might be frightened a little bit, but it's no real cost to you," Slice said. "But if you should ever miss a face and that person wants your head, then that's a serious omission."

Slice said future research may look at whether cars' personalities relate to drivers' habits and interactions.

"Possibilities are if you see an aggressive car in your rear view mirror you may be more like to pull over and yield to it," he said. "By the same token, if you see a submissive or more immature car trying to get into traffic you may be more likely to yield to it and help the innocent little car get into traffic."

Another question is whether drivers have the same personalities as their cars.

Slice got a bit of anecdotal evidence in the parking lot from Gwen Oliver, a custodial supervisor at Florida State, after telling her that her black Eclipse is dominant, aggressive, powerful and "ready to take care of business."

"I am. Everything you said, I'm like that," Oliver told him after she briskly walked over to see why he was interested in her car. "I'm aggressive, I'm straightforward and I'm outgoing and I believe in getting the job done."