MR. KOJO NNAMDILast week, in the aftermath of George Zimmerman's acquittal in the shooting death of Trayvon Martin, President Obama spoke to the nation about why blacks and whites may react differently to the jury's verdict. The president said like that -- like many African-American men, he has seen other people fear him because of his dark skin, women clutching their purses, tighter security following him in department stores.

MR. KOJO NNAMDIWhile many African-Americans view the case through this lens of personal experience, many white Americans insist they're not racist, that they do not judge people by their appearance. But social scientists and diversity experts say it's not always a matter of conscious choice. They say that we are all hardwired to fear and react based on unconscious bias that's part survival instinct and part cultural history.

MR. KOJO NNAMDIJoining me to examine how unconscious bias affects our social interactions is Howard Ross. He visits with us regularly. He's a diversity consultant, principal at Cook Ross and author of "Reinventing Diversity: Transforming Organizational Community to Strengthen People, Purpose, and Performance." Howard, always a pleasure.

MR. HOWARD ROSSYou too, Kojo.

NNAMDIAlso in studio with us, we welcome back Shankar Vedantam. He is science correspondent with NPR and author of "The Hidden Brain: How Our Unconscious Minds Elect Presidents, Control Markets, Wage Wars, and Save Our Lives." Shankar, good to see you again.

MR. SHANKAR VEDANTAMGood to be back here, Kojo.

NNAMDIHoward, most of us think and react out of free choice. But we also have unconscious biases that influence our perceptions and our actions. Explain how our unconscious danger detector works.

ROSSWell, I think one of the things that's important, first, to understand, Kojo, is that human beings have about as much choice about having bias as we have about breathing. We couldn't survive without it. We make constant decisions about what's safe and what's not safe in the world, and we make them quite instantly and quite instinctively. So most of it occurs as a very quick reaction.

ROSSDaniel Kahneman called it fast thinking or fast brain thinking between, you know, the amygdala sends a signal to the limbic system, and we, you know, we do something instantly, and we need to do that. For example, I was driving over here this morning. Person in front of me stopped short in their car, and their taillights come on. I don't stop to consider. Now, let me think. What's the best way to handle this? If I did, I would be in back of that car. My foot instinctively goes to the brake, and we do that in all different areas of our life.

ROSSNow, one of the challenges is that -- and to some degree -- and you and I have talked about this before. To some degree in a diversity space, rather than helping people learn how to watch their biases and to again, use another car metaphor, declutch them, like step on the clutch so that the biases aren't running the show, what we've tried to do is to convince people that we can make them go away.

ROSSAnd in doing that all too often, we've driven them more into the underground and made them less visible. So if I know I'm a good person and I would like to feel comfortable with black people, for example, and then I feel a discomfort, that part of my ego that wants to feel like I'm a good person doesn't want to admit to itself that there may be some inherent unconscious bias in the system. And so in a lot of ways, our political correctness makes us less likely to see our unconscious impulses.

NNAMDILet's look, Shankar, at an example of unconscious bias. A doctor in Massachusetts studied the way physicians evaluate and treat black and white patients. What did he find out about how race influenced their decision?

VEDANTAMI think you're referring to the study by Alexander Green...

NNAMDIYes.

VEDANTAM...from Massachusetts General Hospital, Kojo. And it was a very interesting study because across medicine, we see why disparities -- racial disparities and outcomes if physicians treat white and black patients differently on a whole set of different measures. And often, when those disparities occur, we say, well, this must be the result of intentional bias. The doctors must have conscious animosity toward people of color or toward blacks.

VEDANTAMWhat Alexander Green did was he conducted a study -- this was a study involving physicians in Atlanta and in Boston, and he measured the physician's unconscious biases and how, at an unconscious level, they were biased against African-Americans. And what he found was that the levels of unconscious bias, but not the levels of conscious bias, predicted the kind of care these doctors gave patients.

VEDANTAMSo when doctors thought that they were treating a black patient rather than a white patient, they were more likely to withhold, you know, clock-busting drug if they had high levels of race bias. Now, what's essential to emphasize again is that these physicians were not biased at a conscious level. So when he asked them ahead of time, do you have conscious biases, they said, no.

VEDANTAMAnd yet, when they saw the disparities in the treatment, they were horrified. The physicians were horrified. They said, how was it possible that we, as physicians, trying to do the best by our patients, are producing these radical, you know, radically different results depending on whether the patient is white or black?

NNAMDI800-433-8850. How do you think unconscious bias affects your outlook on the world? Give us a call, 800-433-8850, or send email to kojo@wamu.org. Shankar, another study of how police cadets react at the black and white suspects indicated or illustrated their unconscious bias. Explain the racial disparity in their reactions when they could not tell if a suspect was armed.

VEDANTAMSo this is again a huge issue because periodically, almost every year or every other year, we have a case where police shoots somebody who's unarmed. It turns out, they've made a mistake. There are lawsuits and accusations of bias and racism. You know, the Amadou Diallo case comes to mind. There -- this happens with great frequency. And so, there's been a lot of interest in police academies who try and study the behavior of cadets and try and figure out what's causing these disparities.

VEDANTAMThe specific study that I think you're referring to, I came by, was by Katherine Knight Tuttle. And what she did was again, you know, roughly the same model as what Alexander Green did with the physicians. She measured unconscious bias of these police cadets and then measured how likely they were to shoot in an ambiguous situation. So if you're a police officer and you're pulling somebody over or you meet somebody in a dark alley, you don't know upfront whether the person is dangerous or not.

VEDANTAMSo you're having to make these very quick judgments about whether somebody is a threat or not based on very little information. And what Tuttle found is that there was actually no racial bias when people were actually armed. So when the person was actually armed, you know, it was actually very easy to distinguish and to make the right judgment. It was when people were unarmed that there was a racial bias.

VEDANTAMSo when somebody pulls a wallet out of their pocket or pulls a cellphone out of their pocket, you're now in a situation of ambiguity where a police cadet or a police officer has to make a judgment, is this cellphone a gun? And am I going to get shot in the next 0.5 seconds? And in that 0.5 seconds, you have to make a decision, do I open fire or not? And it's in that kind of situation why you have ambiguity and a rapid decision that needs to be made that bias has the most opportunity to grow.

NNAMDIIn the wake of the Trayvon Martin case, President Obama talked last week about how many African-American men, including he himself, experience racial prejudice. Let's listen.

PRESIDENT BARACK OBAMAThere are very few African-American men in this country who haven't had the experience of being followed when they are shopping in a department store. That includes me. There are very few African-American men who haven't had the experience of walking across the street and hearing the locks click on the doors of cars.

PRESIDENT BARACK OBAMAThat happens to me, at least before I was a senator. There are very few African-Americans who haven't had the experience of getting on an elevator and a woman clutching her purse nervously and holding her breath until she had a chance to get off. That happens often.

NNAMDIStarting with you, Howard Ross, what role might unconscious bias play in the experiences the president talks about?

ROSSWell, I think that one of the things that were clear about is that this notion of bias is not just an individual or personal thing, it relates to our group identity as well. And, you know, Abraham Maslow back in 1943 created his hierarchy of social needs. And in Maslow's hierarchy, he said physiological needs were first, safety needs second and then belongingness. It's been this amazing model for 70 years that has really helped people a lot in understanding human psychology.

ROSSUnfortunately, we're finding out he was wrong, that what current research shows is that belongingness is actually the key for people. That -- and if you think about it, it makes perfect sense. I mean, I had a new granddaughter born three weeks ago. And, you know, her experience of life right now is if her parents don't exist, she dies, you know? We start at the very core of our human existence linking to people, and the sense of belonging is tied inexorably to our survival.

ROSSAnd so when we look at that, what we know is that fitting in -- and there was a Purdue University study just two years ago that showed, for example, that being separated from a group that we identify with triggers the same part of the brain as physical pain. We need to connect. So when something happens to a person, if we relate to that group, then we know that we have a particular relationship to what happens to that group as a personal attack on ourselves.

ROSSAnd, in fact, a couple of other studies from MIT, from Peking University, have shown that people have a lot more empathy for people who they identify with. That if you're part of my group, I have a natural tendency to have empathy for you more than if you're a part outside of that group. So let's go back to your question relative to the Zimmerman trial.

ROSSPew just came out with a study that found that when we look at what white people say about the trial, 49 percent of whites were satisfied with the verdict, 30 percent of blacks, 5 percent -- I mean, 30 percent dissatisfied, 5 percent of blacks were satisfied with the trial, 86 percent dissatisfied. We're back to O.J. again. So our group identity impacts what we see in a very profound way and quite automatically. And if we're part of that community, the community view of it begins to take over our individual view of it in quite -- and sometimes in an unconscious way as well.

NNAMDIShankar, same question. What role might unconscious bias play in the experiences that President Obama talks about?

VEDANTAMWell, you know, if you're the victim of this, if you're an African-American man and this has happened to you over the last 25 years, you know, you can understand why it's just profoundly upsetting and humiliating that this will happen over and over again, that you would have to show people or feel the need to show people that you are not a threat, that you are actually a safe person.

VEDANTAMAt the same time, I think the unconscious bias literature, I think, Kojo, is very instructive in that it changes one important thing, which is when people traditionally think of bias, they think of saying, you know, racism is a problem that white people have and black people are the victims. But when you look at the unconscious bias literature, it actually turns out to be much more complex than that. Black people often have the same biases against other African-Americans as white people do.

VEDANTAMAnd if you look at the unconscious bias research, it very clearly shows that black physicians and black police officers can be just as biased against black motorists and black patients as white physicians and white cops. And, you know, so from the point of view of President Obama's experience, I think, there's two ways to look at it from the point of view of the receiver of such prejudice.

VEDANTAMIt's profoundly upsetting, and it's profoundly disturbing. At the same time, all of us, white and black, including perhaps the victims of these prejudices, are also guilty of the prejudices ourselves. And so, the unconscious bias literature, I think, complicates the notion of who is victim and who is perpetrator because it suggests, at different times, all of us might be both.

NNAMDI800-433-8850. We got an email from Mike in Baltimore, who says, "When the president mentioned doors locking, I thought, well, I lock my doors when I enter the car. Why? Because my driving teacher told me it would prevent me from being ejected in an accident. No bias. Is this some excess paranoia by black males in this one small case?" Howard?

ROSSWell, I think that here you have an example of a -- a perfect example of what we're talking about, a behavior. It is behavior that everybody engages in at different times. But a particular group notices a pattern that others don't. If I'm walking across the street, I very rarely hear -- as a 62-year-old white man, I very rarely hear all of a sudden doors locking among people in the street. This is not when I'm getting into my car to drive. It's when I'm -- when somebody's sitting at the stoplight.

ROSSAnd yet young African-American men experience that all the time. They hear that door locking. They see a woman clutching the purse as the president was talking about. They experience certain behaviors that become pattern. Now, of course, another part of this is that, you know, we have a phenomenon of our mind which sometimes is referred to as perceptional organization and that is we begin to organize our minds to see the things that we expect or that are normal for us.

ROSSThis is a phenomenon how pregnant woman see pregnant women everywhere. So the other side of that is, that if you're a young black man and you've had somebody lock their car a certain number of times, you are also more sensitive to people locking their cars whereas a white man might not notice it. So there are two sides to this that are going on all the time.

ROSSAnd as Shankar was saying, we're all in the soup with this. And by the way, just -- additionally to say, we also have studies that show similar unconscious biases about height, about weight, about hand dominance -- right hand, left hand -- about accent, about appearance, about sexual orientation and about virtually every other distinction between human beings that you can tell. So we're all doing this. It's just sometimes, obviously, it has a much broader societal impact.

NNAMDIGot to take a short break. When we come back, we will continue our conversation on unconscious bias with Howard Ross and Shankar Vedantam. You can still -- well, the phones are busy, so send us an email to kojo@wamu.org or a tweet, @kojoshow. I'm Kojo Nnamdi.

NNAMDIWelcome back. We're discussing the science behind unconscious bias with Shankar Vedantam. He is science correspondent for NPR and author of "The Hidden Brain: How Our Unconscious Minds Elect Presidents, Control Markets, Wage Wars, and Save Our Lives." And Howard Ross, diversity consultant, principal at Cook Ross and author of "Reinventing Diversity: Transforming Organizational Community to Strengthen People, Purpose, and Performance."

NNAMDILet's look at the question of intentional versus unconscious motivation. In this country, criminal law is largely based on intent. Prosecutors usually have to prove some sort of intention to do harm to win a conviction. Might it be time to rethink that framework and hold people accountable for unconscious motivation as well? Starting with you this time, Shankar.

VEDANTAMWell, this really raises a profound question, Kojo, because when you think about how the law works in all kinds of different issues but especially in the criminal justice system, you know, we actually ask, how intentional was this harm? If somebody kills somebody else, did they intend to do it? Was this premeditated? Was there actual animosity? Was there, you know, was there animus that drove this behavior?

VEDANTAMAnd we judge those cases very differently. Now if you think about it from the point of view of unconscious bias and you say some of these behaviors might be driven by factors that people are not even aware of, the law, in some ways, isn't very good at grappling with that kind of problem. So the outcomes are real. The disparities are real. The tragedies and consequences are real.

VEDANTAMBut the way we judge them typically and saying bad things must have been caused by bad intentions, breaks down when it comes to unconscious bias. So in some ways, yes, I think, you know, we do need to have a rethink about how we can apply the unconscious bias literature and the findings from it to legal settings.

VEDANTAMBut it might be also be the case, Kojo, that the law and courtrooms might not just be the best place to try and work these things out, that these are complex issues involving behavior, and the courts are really not set up to psychoanalyze people, to understand the inner workings of motivation and to really help people change because in some ways, the perpetrators of, you know, biased actions that are caused by unconscious bias, in some ways are the victims, too.

VEDANTAMIf I'm acting in a biased way and I don't even realize I'm acting in a biased way, to some extent, I'm a victim, too, of my own biases. And what you should be doing is trying to help me, not necessarily prosecute me.

NNAMDIHoward.

ROSSYeah. I absolutely agree. And it also brings up the question of how much the structural issues impact our behavior. I mean, it really could take us back to the Lt. Calley case back in the My Lai massacre because, you know, here you had a case where somebody performed a behavior -- was put into a situation in which, you know, the norms, the behavioral norms, the means that he was experiencing in that situation called for particular kind of behavior.

ROSSIt gets back to what Shankar was saying about the police officers. You know, you're trained as a police officer to be careful, to watch out, it could be dangerous. You have half a second to make that determination. And the norms of the culture that you're a part of call for a particular behavior. You behave that way in that circumstance reactively and then step back and say, oh, my God. Somebody's dead. And it was an innocent person who was dead.

ROSSAnd the problem is that the courts can't handle this well. There's no way that we can read people's minds and actually know at the moment whether they made that determination intentionally. The impact is no different. If I'm cleaning my gun and Shankar got shot by it, it's no different than if I'm intending to shoot him. So we know the impact is no different. But the fundamental assumption of free will that we have is one of the things that clouds what we're doing because very little, very few of the decisions we make are actually based on free will.

NNAMDIOn to David in Martinsburg, W.Va. David, you're on the air. Go ahead, please.

DAVIDHi. Thank you, Kojo. First of all, I guess I should say I do not consider myself to be a racist at all. I'm a large white male. But in -- I'll say this as well. I have many family -- many friends from different countries, colors, ethnicities. My sister-in-law is Filipino. So I don't consider myself to be a racist. It never came up in my family growing up. It's a fact which I'm very proud of.

DAVIDHowever, I own a business, and I transport cash near a lower-income area. I frequently work late, and I see people who appear to me to be rough. And even though I consider myself to be, you know, large, I shouldn't be afraid. Sometimes I am when I'm transporting cash. So I'm wondering, is that -- would you all consider that to be racist, or would you consider that to just be a healthy normal fear? Tell me your thoughts.

NNAMDIWell, I'd just be interested to hear Howard Ross.

ROSSAs another large white man, yeah.

NNAMDIExactly right. Who I do not fear.

ROSSLook. I think, David, your question points exactly to the point that Shankar was talking about earlier, which is that there is this conversation about, am I a racist? And then there's this other conversation about the unconscious wiring that we have. When we use the terminology racist in our culture, we generally associate that with a notion that this is somebody who hates a particular group of another race or dislikes that group of another race, or fears them intensely and, therefore, acts in accordance with that. Those feelings may or may not be conscious to us.

ROSSNow it's very difficult for most people in our culture to not have feelings of fear about African-American men including, as Shankar said, even African-Americans themselves because of the constant patterning that we see of negative stereotypes, negative representations that reinforce that notion. And we may not want to have those feelings, not believe we have those feelings, but it may still be in us.

ROSSNow one challenge is because we demonize those feelings, we say having bias is bad and wrong and because we're so afraid of bias rather than saying, well, let me look and see. There might be some unconscious bias here. I have to be aware of that and be careful and, you know, check that, that it doesn't affect my behavior. But instead, we say, God, if I have bias, I'm a bad person. Therefore, can't be biased.

ROSSSo I think we all struggle with that. And I know, I've had moments where I've had -- you know, I've worked -- I started to work in civil rights when I was a teenager. I spent the last 45 years of my life working committed to racial justice. And I have tons of people in my life who were all different races, including, you know, four grandchildren who are of mixed race, and I still notice that those feelings come up for me. The machine spits out those thoughts regardless of my intention.

NNAMDIAnd I noticed that David said the people who he has to deliver the cash near in a poor neighborhood appear to be rough. We got this email from John in Arlington. "I have noticed that I respond to what others are telling me by their dress more than their personal characteristics. So someone looking like a nurse gets my nurse response.

NNAMDI"Someone looking like a gang member gets my gang member response. And with relationship to that and appearing to be rough, a lot has been made of the hoodie that Trayvon Martin was wearing. I suspect there's an age gap there because I know that most people under 50 years old today own at least one sweatshirt with a hoodie."

ROSSAnd many over 50.

NNAMDIAnd many over 50. I own about three myself actually.

ROSSYes, exactly.

NNAMDIBut, Shankar, I wanted to go with this. Talk about the racial prejudice that existed. How much is outright animosity or hatred, and how much is unconscious bias?

VEDANTAMSo it's really difficult to quantify how much is one and how much is the other. If you actually go by the data, virtually no one in any United States today admits to being prejudiced on any count. And so in terms of conscious prejudice, if you take people at their word, you know, there's just very little unconscious prejudice in the United States today.

VEDANTAMHowever, if you look at the outcomes in the criminal justice system, in medicine, in the law, in education in a whole manner of the whole range of different fields, you have enormous racial disparities in hiring, promotions, you know, all kinds of different issues. And so, you know, I think the better question to ask is not so much what's happening inside people's hearts because that's actually difficult to get at, but to look at outcomes and to say what is actually causing these disparity outcomes that we're seeing.

VEDANTAMI believe that the bulk of the disparity outcomes that we're seeing, the disparities and outcomes, are stemming from unconscious bias. They're coming about because large numbers of people, without their awareness, are following scripts and heuristics that basically prompt them to behave in certain ways and unintentionally are producing outcomes that are deeply flawed, deeply ethical. Now, it's important to emphasize because these are unintentional, doesn't mean the consequences aren't real.

VEDANTAMIn 21st century America, it is unconscionable that the black infant mortality rate is 30 to 40 to 50 percent higher than the white infant mortality rate. That is just simply unconscionable. But I think it's an error to go from that terrible outcome to basically say this terrible outcome must have been caused by conscious animosity and bias. I don't believe the research backs up that contention.

NNAMDIHoward, let's talk about how to address unconscious bias because that...

ROSSOK -- I'm sorry. That...

NNAMDIGo ahead.

ROSSI apologize. I just wanted to...

NNAMDI'Cause I think you could include your response in this.

ROSSYeah. OK. Go ahead.

NNAMDIWhen President Obama spoke to reporters last week, he said he was skeptical of calling for a national conversation on race. He also said it was time for us all to do some soul-searching. How can each of us examine our own subconscious biases? And you can also respond to the other...

ROSSYeah. OK. Great. I was just going to add to what Shankar was saying that actually our misunderstanding about this ends up reinforcing the phenomenon. So let's take the Tea Party, for example. Now, anybody who looks at the Tea Party -- and the signs in those crowds know that there was race involved in some of those reactions. But those people may not see it that way. They may not see the races there.

NNAMDIThey have said they don't.

ROSSSo then they hear African-American say this is about race. And the defense mechanism, the inner protector says, don't accuse me of that. You're just saying that because you're black. And so that intensifies the reaction. And so we get into these cycles where our unwillingness, our inability to look at what's actually going on actually reinforces the surface phenomenon. Now, I happen to believe -- or agree with the president that this isn't something that gets off by bringing in a bunch of people together to talk about it.

ROSSAnd the work that we're doing, as you know in organizations, is helping people in the organizational level learn not only about their own bias and ways that you can deal with it but by putting structures in place. So there are number of things that we know. There's one thing that we know is most important, which is to recognize that you have bias no matter who you are -- the Dalai Lama has bias, we all have it -- and rather to defend against it to do some work on observing it in yourself.

ROSSWe also know through research that being exposed to people from other groups to those who we consider the other and particularly the positive avatars or counter-stereotyping from those groups can help soften those biases. So those are some of the things. There are other things we can do.

ROSSOrganizationally, we can do things like, for example, before people do interviews, when they're looking at the resumes, that we found, if you give them a series of questions to ask about their own reaction to the resume, that that can help bring the biases up to the surface so that they're more in their mind to process on a conscious level before they interview that person.

ROSSAnd, you know, there are lots more that we're doing organizationally, whole sets of those kinds of mini tools that you can put in place to help people do that. But it starts with this awareness that bias is not something to be afraid of but rather something to observe.

NNAMDIAnd, Shankar, researchers at the University of Virginia recently challenged their fellow scholars to come up with ways to breakdown unconscious bias. One Harvard psychologist found that images countering common stereotypes were particularly effective. How did she use them?

VEDANTAMYeah. So this was a study that was run by almost more than a dozen groups of researchers across United States and across the world actually. Calvin Lai and Brian Nosek of the University of Virginia were instrumental in setting up the research study. And the challenge was, you know, the groups of scientists were told, we know that this unconscious biases exists and that they are widespread. Let's do something about that. Come up with the interventions that have to, in a very quick manner, reverse the unconscious biases on these tests.

VEDANTAMSo what can you do in five minutes that could reverse somebody's unconscious race bias, for example? And these different teams of researchers came up with different things. Some of them said, let's teach people about the history of injustice. Let's teach people about the history of segregation. And surprisingly, what they found is that education and asking people to be emphatic toward others was almost completely ineffective, that it did very little to change people's unconscious biases.

VEDANTAMMahzarin Banaji at Harvard told me that what was effective was exposing people, as Howard just said, to counter stereotypes, that when you ask yourself consciously to think about positive avatars, to think about positive examples that run against your (word?) stereotype, you're much less likely to hold those stereotypes.

NNAMDIThere's one particularly good one I want you mention before we go.

VEDANTAMWell, you know, so one of the examples that she gave me was she said she had this image on her screensaver, which has a woman at a construction site that was -- who was nursing her baby. And she talked about how that image of this woman wearing a hard hat and nursing her baby at the construction site just pulls her internal assumptions in so many different directions that she was hopeful that it would help, you know, open her mind in other situations as well.

NNAMDIMake you soul search every single day. Shankar Vedantam, a science correspondent with NPR and author of "The Hidden Brain: How Our Unconscious Minds Elects Presidents, Control Markets, Wage Wars, and Save Our Lives." Howard Ross is a diversity consultant and principal of Cook Ross, author of "Reinventing Diversity: Transforming Organizational Community to Strengthen People, Purpose, and Performance." Thank you both for joining us.

ROSSThanks, Kojo.

NNAMDIThank you all for listening. I'm Kojo Nnamdi.