New research suggests bias also can be found within racial categories.

A community march against racism. (Photo: Caelie_Frampton/Flickr)

Over the years, a disturbing amount of research has suggested that the amount of discrimination faced by African Americans is, to some degree, a matter of skin tone. A few examples:

A 2006 study of job applicants found a light-skinned black man can have only a bachelor’s degree and still be preferred over a dark-skinned black man with an MBA.

A 2010 study found black women in North Carolina with lighter skin tones received more lenient prison sentences and spent less time behind bars.

In January of last year, a study found highly educated African Americans are later remembered as being “whiter” than they are in real life.

While there is a clear pattern here, the evidence is, by its nature, inferential. But in a newly published study, Villanova University sociologist Lance Hannon presents the most concrete findings yet that whites’ impressions of blacks and Latinos depends in part on their skin tone.

Using data from the 2012 American National Election Study, he finds that “African American and Latino respondents with the lightest skin are several times more likely to be seen by whites as intelligent, compared with those with the darkest skin.”

This prejudice, whether conscious or not, “could create substantially unequal access to economic, social, and cultural resources,” Hannon writes in the journal Social Currents.

The National Election Study is a face-to-face survey in which respondents answer a variety of questions about politics. They also disclose their income and education level, and take a brief vocabulary test.

Hannon narrowed his search down to 223 African Americans or Hispanics who were interviewed by white survey takers. The interviewers were instructed to list each person's skin tone on a 10-point scale.

Interviewers were asked to gauge each person's "apparent intelligence" on a five-point scale from "very low" to "very high." "Interviewers were not allowed to opt out," Hannon notes. "Thus the question can be seen as tapping into deep prejudices."

The results suggest it did just that.

"African Americans and Latinos deemed to have lighter skin tones were significantly more likely to be seen as intelligent by white interviewers," Hannon reports. Further analysis found the interviewers had a distinct tendency to "look at two identically qualified minorities and assess the lighter skinned one as more intelligent."

"Importantly, the effects of skin tone on intelligence assessment were independent of respondent education level, vocabulary test score, political knowledge assessment, and other demographic factors," he adds.

While dismaying in themselves, these results have even more disturbing implications. "If white adults have a tendency to equate lighter skin with intelligence," Hannon writes, "this may impact the quality and level of expectations white teachers and other school authorities have for certain students."

The findings provide further evidence that racism is a more complicated phenomenon than we generally realize. Along with the aforementioned earlier research, it suggests discrimination can occur within racial categories, as well as between them.