What media sparked racial violence in the early 1900s

television

magazines

newspapers

radio

Television and even radio was not widespread or even used in the early 1900s.

You could answer magazines, but these are only periodic (like once a month) publications. They are the second best answer however.

The answer is newspapers. They had a daily chance of reminding people that the group to hate this month was .  The Jews Italians Irish and Arabs were targets in the early 1900s.

sir frederic attributed inaccuracies to schemas. memory reconstruction is one part actual events and one part personal schema, which can result in inaccuracies when memories are reconstructed.