My colleague Maxine Williams, head of diversity at Facebook, told me that she believes many people succumb to the mum effect around race. 'Even after an unarmed black person is killed for reaching over to show a cop his license, white people who have seen the news, who live in these communities, and who sit at the desk next to us at work will often say nothing,' Maxine said. 'For the victim of racism, like the victim of loss, the silence is crippling. The two things we want to know when we're in pain are that we're not crazy to feel the way we do and that we have support. Acting like nothing significant is happening to people who look like us denies us all of that.