This is because interviewers can be distracted by unusual facial features and recall less information about job candidates, according to the investigators at Rice University and the University of Houston.

"When evaluating applicants in an interview setting, it's important to remember what they are saying," Mikki Hebl, a psychology professor at Rice University, said in a university news release. "Our research shows if you recall less information about competent candidates because you are distracted by characteristics on their face, it decreases your overall evaluations of them."

One experiment involved about 170 undergraduate students who conducted mock interviews via a computer while their eye activity was tracked. The more the interviewers' attention was distracted by facial blemishes, the less they remembered about the job candidate and the lower they rated them.

In a second experiment, 38 full-time managers conducted face-to-face interviews with job candidates who had a facial birthmark. All the managers had experience interviewing people for jobs but were still distracted by the birthmarks.

"The bottom line is that how your face looks can significantly influence the success of an interview," Hebl said. "There have been many studies showing that specific groups of people are discriminated against in the workplace, but this study takes it a step further, showing why it happens. The allocation of attention away from memory for the interview content explains this."

The findings were recently published online in the Journal of Applied Psychology.

The investigators said they hoped their research would help raise awareness about this type of workplace discrimination.