White liberals present themselves as less competent when addressing minorities, while conservatives use the same vocabulary no matter what the race of their audience, according to a newly released study.

Yale and Princeton researchers found that white Democratic presidential candidates and self-identified liberals played down their competence when speaking to minorities, using fewer words that conveyed accomplishment and more words that expressed warmth.

On the other hand, there were no significant differences in how white conservatives, including Republican presidential candidates, spoke to white versus minority audiences.

“White liberals self-present less competence to minorities than to other Whites — that is, they patronize minorities stereotyped as lower status and less competent,” according to the study’s abstract.

Cydney Dupree, assistant professor of organizational behavior at the Yale School of Management, said she was surprised by the findings of the study, which sought to discover how “well-intentioned whites” interact with minorities.

“It was kind of an unpleasant surprise to see this subtle but persistent effect,” Ms. Dupree said. “Even if it’s ultimately well-intentioned, it could be seen as patronizing.”

The study flies in the face of a standard talking point of the political left — that white conservatives are racist — while raising questions about whether liberals are perpetuating racial stereotypes about blacks being less competent than whites.

The paper, which is slated for publication in the Journal of Personality and Social Psychology, first examined speeches by Republican and Democratic presidential candidates to mostly white and mostly minority audiences dating back 25 years.

Ms. Dupree and Princeton’s Susan Fiske analyzed the text for “words related to competence” such as “assertive” and “competitive” and “words related to warmth” such as “supportive” and “compassionate.”

“The team found that Democratic candidates used fewer competence-related words in speeches delivered to mostly minority audiences than they did in speeches delivered to mostly white audiences,” said the Yale press release. “The difference wasn’t statistically significant in speeches by Republican candidates.”

Ms. Dupree noted that Republicans also gave fewer speeches to minority audiences.

The researchers then set up an experiment in which white liberals were asked to respond to hypothetical individuals named “Emily” and “Lakisha.”

“Liberal individuals were less likely to use words that would make them appear highly competent when the person they were addressing was presumed to be black rather than white,” said the release. “No significant differences were seen in the word selection of conservatives based on the presumed race of their partner.”

Ms. Dupree said the “competence downshift” could indicate a greater eagerness by white liberals to connect with those of other races.

“My hope is that this work will help include well-intentioned people who see themselves as allies but who may be unwittingly contributing to group divides,” said Ms. Dupree. “There is a broader need to include them in the conversation.”