A flashy handbag or Armani suit can signal a person's wealth, but so can their body language, according to a new study. People of higher socioeconomic status are more rude when conversing with others.

Psychologists Michael Kraus and Dacher Keltner of the University of California, Berkeley, videotaped pairs of undergraduate students who were strangers to one another, during one-on-one interviews. In total, 100 undergraduate students participated.

The researchers then looked for certain gestures that indicate level of interest in the other person during one-minute slices of each conversation.

They found that students whose parents were from higher socioeconomic status (SES) backgrounds engaged in more of what he called "impolite" behaviors, such as grooming, doodling and fidgeting. Lower SES students showed more "I'm interested" gestures, including laughter and raising of the eyebrows

The higher SES students fidgeted with nearby objects for an average of two seconds, while those from lower SES backgrounds almost never fidgeted during the 60-second clips. Upper SES students also groomed themselves for short stints while lower SES students didn't. Rather, the lower SES students nodded their heads, laughed and raised their eyebrows an average of one to two seconds more than their upper SES counterparts.

"We're talking seconds here, but that is a pretty big difference when you consider that we coded one minute of interaction time," Kraus told LiveScience. "So how many times a day are you nodding if you're lower socioeconomic status?"

It comes down to our animalistic tendencies, Kraus explained. Like a peacock's tail, the seemingly snooty gestures of higher SES students indicates modern society's version of "I'm fit," and "I don't need you."

"In the animal world, conflict arises when you're battling for status. So it's adaptive for us to avoid those conflicts and tell us we know 'I'm higher status than you, so don't bother having a conflict with me,'" Kraus figures.

Lower SES individuals can't afford to brush off others. "Lower SES people have fewer resources, and by definition should be more dependent on others," Kraus said.

The research is detailed in the January issue of the journal Psychological Science.