Like so many people, I’m deeply saddened and angry about the tragic killing of Trayvon Martin. And like so many people, I know that in no way is Trayvon’s murder an isolated incident. In my op-ed for Reuters, I explore what scientists tell us about implicit racial bias — and what it means for Trayvon, President Obama and America.

In one study, researchers used computers to generate several faces that were exactly the same except for the skin color — half were black and half were white. All respondents (yes, including black people studied for the project) were more likely to rate the black faces as showing greater hostility. In another study, scientists showed a group of subjects a video of one person pushing another person. When the “shover” was black and the “victim” was white, 75 percent of research subjects said the push was aggressive. When the “shover” was white and the victim was “black,” only 17 percent of subjects said the push was aggressive.

Implicit racial bias has also been found in what researchers call a “shooter bias” — in which subjects playing a simulated video game are more likely to mistakenly pull the trigger on unarmed black men than on unarmed white suspects. The phenomenon has been tested and proved with police officers, too.

Watching conservative attacks on Obama, it’s hard not to conclude that they are tainted by implicit bias. Consider: President Barack Obama is the first African-American president of the United States of America. From day one, conservatives have attacked the president’s religion, citizenship and essential patriotism. Conservatives condemned healthcare reform in general and the individual mandate in particular, even though the mandate was originally a Republican proposal. Republicans, who historically never met a tax cut they didn’t like, have opposed virtually every tax cut proposal that President Obama has put forth. Amidst high unemployment and a crumbling economy, Republican Senate Minority Leader Mitch McConnell said his number one goal was to destroy the president’s chance for re-election.

Now, I do not believe that Mitch McConnell or most Republican leaders or rank-and-file voters are overt racists. But their rhetoric often evokes the same racial animus that Zimmerman seems to have expressed. Republican presidential candidate Newt Gingrich has labeled President Obama “the most dangerous president in history.” Glenn Beck once accused President Obama of having a “deep-seated hatred of white people.” And long before he called Sandra Fluke a slut, conservative mascot Rush Limbaugh said: “Obama is an angry black guy.” The parallel imagery is clear: President Obama, like Trayvon Williams, is a dangerous, suspicious black man clearly up to no good, guilty of Governing While Black.

It’s a much longer piece. You can read it here. And please share your comments and help spread it around — this is a conversation our nation needs to have.