Pity the poor, forlorn foreign graduate teaching assistant at an American university – far from home and family, living on a meager stipend, cramming by day and grading by night, fielding questions from undergraduates like “Do people wear regular clothes in your country?” or “Are any of your relatives terrorists?”

Of the many indignities international students endure, accent discrimination may be the most mortifying, in part because it is still widely accepted in our society. Like skin color or attire, accent is a characteristic we routinely use to identify someone as unfamiliar or foreign. But while most people understand that discrimination based on visual appearance is wrong, bias against foreign speech patterns is not universally recognized as a form of prejudice. Title VII of the Civil Rights Act of 1964 prohibits discrimination based on national origin, but is mum on the subject of accent bias. Moreover, employers who deny jobs to non-native speakers can protect themselves by arguing that a foreign accent impairs communication skills essential to the workplace.

As intuitive as this argument may seem, however, evidence of on-the-job “accent impairment” is scarce. And for all the hue and cry undergraduates have raised over the years about “unintelligible” non-native instructors, numerous studies have failed to detect any significant differences in performance between students taught by native English and non-native instructors. So why do foreign accents still get a bad rap in the ostensibly open-minded oasis of academia and beyond?

New research by University of Chicago psychologists Shiri Lev-Ari and Boaz Keysar suggests that prejudice is only part of the problem. Non-native accents make speech somewhat more difficult for native speakers to parse and thereby reduces “cognitive fluency” – i.e., the ease with which the brain processes stimuli. And this, they found, causes people to doubt the accuracy of what is said.

Not surprisingly, people prefer stimuli that are easy to process to those that are hard. In recent years, psychologists have explored the surprising extent to which our preference for the easy influences our thinking. For example, studies of stock purchases have shown that shares in companies with names that are easy to pronounce are bought at higher rates than others that are harder to pronounce. Other studies have shown that when people judge a statement’s accuracy, manipulations that make the statement easier to mentally process -- even totally irrelevant changes like putting it in a cleaner font or making it rhyme -- can alter people’s judgment of its truth, along with their evaluation of the intelligence of the statement’s author and their confidence in their own judgments and abilities.

Lev-Ari and Keysar hypothesized that the difficulty of understanding accented speech has a unique effect on a speaker’s credibility that cannot be attributed to stereotypes about foreigners. A good test case for this idea would be a speaker who is simply delivering a message from a native speaker. If people find the message less believable when the messenger has an accent, then the judged credibility is impacted by the cognitive fluency associated with processing speech, not by prejudice.

Lev-Ari and Keysar put this idea to the test in a simple experiment. They asked people to judge the truthfulness of trivia statements were recited by either native or non-native English speakers. (Example: A giraffe can go without water longer than a camel can.) The non-native speakers had mild or heavy Asian, European, or Middle Eastern accents. The subjects were told that all the statements had been written by the researchers but, still, the subjects tended to doubt them more when recited with an accent.

In a second experiment, participants were explicitly told that the goal of the research was to study how the difficulty of understanding people’s speech might affect the perceived credibility of their statements. Statements were still judged as less truthful when spoken in heavy than native accents, although participants were able to correct their judgments for mild accents.

These findings have important implications for how people perceive non-native speakers of a language, particularly as mobility increases in the modern world, leading millions of people to be non-native speakers of the language they use daily. Instead of perceiving their speech as harder to understand, natives are prone to perceive their statements as less truthful. Consequently accent might reduce the credibility of non-native job seekers, court eyewitnesses, or college instructors for reasons that have nothing to do with xenophobia per se.

But the ramifications of cognitive fluency are not all bleak for the intrepid immigrant and international visitor. Several recent studies suggest that modest disruptions of cognitive fluency – cases of cognitive “disfluency,” if you will – prompt people to think critically. For example, University of Michigan psychologists Norbert Schwarz and Hyunjin Song found that formatting a test in a difficult-to-read font dramatically decreased the number of people tripped up by trick questions like “How many animals of each kind did Moses take on the Ark?” [Answer: None – Moses wasn’t on the Ark, Noah was]. In effect, making people work harder to process the test questions made them less likely to make careless mistakes. College students, take heed: practice parsing your non-native teaching assistant’s accented speech might well augment your analytical skills.

Are you a scientist? Have you recently read a peer-reviewed paper that you want to write about? Then contact Mind Matters co-editor Gareth Cook, a Pulitzer prize–winning journalist at the Boston Globe, where he edits the Sunday Ideas section. He can be reached at garethideas AT gmail.com