As protests against racism started sweeping across America and rest of the world, clips of Jane Elliott, a schoolteacher turned anti-racism educator, began circulating on social media.

Perhaps you’ve seen them.

In one grainy clip from 2001, Ms. Elliott, with her signature round glasses and clipped white hair, gets into such a heated argument with a white female college student during an educational exercise about racism that the uncomfortable and distraught woman starts crying and storms out of the classroom.

“You just exercised a freedom that none of these people of color have,” Ms. Elliott tells the student, sternly. “When these people of color get tired of racism, they can’t just walk out.”

Or maybe you’ve seen the 2018 video of Ms. Elliott in a round-table discussion on racism with the actress and producer Jada Pinkett Smith, Ms. Pinkett Smith’s daughter, Willow, and Ms. Pinkett Smith’s mother, Adrienne Banfield-Norris.

“I’m not a white woman. I’m a faded Black person,” Ms. Elliott says, stunning the hosts. “My people moved far from the Equator, and that’s the only reason my skin is lighter.”

“Wow,” Ms. Pinkett Smith says back. “I’m with you, Jane!”

Ms. Elliott, now 87, said she started teaching about racism on April 5, 1968 — the day after the Rev. Dr. Martin Luther King Jr. was assassinated.

At the time, she was a third-grade schoolteacher in the all-white Iowa town of Riceville, and the news of Dr. King’s death so shocked and moved her that she threw out the lesson plan for the next day and came up with a new one that would force the children to experience prejudice and discrimination firsthand.

In what is now known as the “Blue Eyes, Brown Eyes” exercise, she split up her class into two groups based on an arbitrary characteristic: eye color. Those with blue eyes were better, smarter and superior to those with brown eyes, she told her students, and therefore they were entitled to perks, like more recess time and access to the water fountain.