Park Goers Reaction to Interracial Couples Fighting

In this clip an experiment is conducted to show how the public reacts to abuse in a biracial relationship. In the first experiment it is a white boyfriend and African American girlfriend. One male passerby stops but doesnt interfere.

Two female passersby lead the girlfriend away from the boyfriend. In the second part of the experiment, they used an African American boyfriend and a white girlfriend. In both situations, women were most likely to help. What does this say about helping those similar to ourselves? Why might men not be as eager to help?