The students tested at San Francisco State University were shown words like "ignorant" and "educated" for 33 milliseconds. These subliminal prompts are part of a phenomenon known as priming, a manipulation by researchers that preps participants' minds for a given experiment. After the subliminal word, they saw a picture of a Black man.
Priming is a powerful tool for psychologists. Basically, simple words or cues activate semantic networks in the brain and make the ideas connected to that semantic network easier to access. The effect is commonly illustrated by a simple experiment: When a researcher hands a person a cup of warm water, they're more likely to describe someone as being warm or friendly. In flashing the word "ignorance" before their participant's eyes, the psychologists make everything with an "ignorance" association in their participant's mind all the more accessible.
What they found was this: The students primed with "educated" were more likely to rate the Black man's skin tone as lighter on a memory test later. "Black individuals who defy social stereotypes might not challenge social norms sufficiently but rather may be remembered as lighter, perpetuating status quo beliefs," the authors summarize. That is, when primed to think of a "Black person" and "educated" in the same mental space, the Black person becomes Whiter. The stereotype distorts the memory.