Home » Uncategorized » Article review – Across the Thin Blue Line.

Article review – Across the Thin Blue Line.

Today I wanted to share an article I had read a few years back. It was entitled…

“Across the Thin Blue Line: Police Officers and Racial Bias in the Decision to Shoot,”

By: Correl, J., Park, B., Judd, C.,Wittenbrink, B., Sadler, M., and Keessee, T., (2007).

Racism in America has long been a touchy subject, and it is always interesting to see what a new set of researchers are trying to discover. In this instance, Correl et. al., (2007) wanted to see if police officers had a tendency to shoot Black individuals more readily than White individuals.

For the sake of clarity, I want to quickly discuss the terms White, Black, and African American. If I see a Black man and describe him as African American, I am assume something, aren’t I? I am assume that since he has dark skin pigmentation and he is in the United States he must be an African American. If I were in Britain, would the term change? Actually, in Britain, some people refer to this group as “Black British.” When someone uses to term Black, it should not be seen as offensive in and of itself, just as the term White should not. Note that these terms are capitalized when referring to people in such groups.  Now I will admit, that categorizing people by skin pigment is actually really offensive, but as social scientists, we have seen people with different skin color get treated vastly different. I know this is a touchy subject, but I just wanted to be clear. If you do not like my comments on the terminology, please take it up with my sociology professors!!! (just kidding!)

Moving on, the researchers were definitely asking a scary question. Is it easier for a police officer to come to the decision to shoot a Black suspect compared to a White suspect? How could they possibly test this, and how would they explain their their findings?

Correl et. al., (2007) put together a game for police officers to play. They were instructed that people would appear on a screen in front of them, and they would be holding objects. The objects would be something like a cellphone, a can of soda, or a gun. Sometimes the gun was silver, other times it was black, as were the phone and soda cans.

In front of the officers were two buttons. One said “shoot,” the other said, “don’t shoot.” The game required that they shoot a person holding a gun, but choose don’t shoot if they are holding a non-gun object. They would then measure how long it took the police officers to come make their choices. Why does time (latency) matter, though?

Latency is important because the authors suggest that if something confirms our current ideas (mental constructs) about a given thing, then we have an easier time coming to our decision. It requires less thought from the prefrontal cortex (working memory), and thus you see a faster response time. So what does this mean for the study? It means that if officers had any underlying stereotypes working against them, they would be able to choose “shoot” when a Black man was holding a gun faster than when a White man was holding a gun. Further, they would find that when a Black man was not holding a gun, it would take them much longer to hit “don’t shoot” compared to a White man holding a non-gun object. Let’s break this down one more time. The author’s assume that seeing a Black man holding a gun was consistent with the officers stereotype, resulting in a faster response time. When the Black man was not holding a gun, this was dissonant with the stereotype, requiring more effort from the working memory, resulting in a longer response time. When a White man was holding a gun, this was dissonant with the stereotype, thus longer response time. Finally when it was a White man holding a non-gun object, the officer would be able to choose quickly as it is consistent with the stereotype.

So what happened?


First lets talk about how to read the graph, then the results should become quite clear. In this version of the study, we see that officers from two samples scored about the same, and so did the community members living in Denver. Lower scores on this chart means that a response time was faster. Thus we see that officers, and people of the general community always responded fastest to a Black man holding a gun. We also see that when a Black man was holding a non-gun object, the response time was slower. This is exactly what was predicted, and exactly what we would expect based on stereotypes, cognitive dissonance, and the impact on working memory.

When we inspect the chart further, we notice the scale is a bit misleading. We are looking at a 10-20 miliseconds difference in response rate, right? Yes, but we are seeing a consistent difference! Remember in my recent statistical post when I mentioned that outliers and variance is common in small samples? This chart represent 124 officers, and 135 community members. This is by no means a small sample size. Given the consistency of the effect, we would say it is statistically sound.

I’m sure many people are wondering if the majority of the sample was White. They would be right! However, would it surprise you that the study was replicated using a sample of Black, Asian, and Latino individuals? Further, when they only look at the Black member’s responses, they were identical to the first sample in just about every way! I was quite surprised, to say the least.

This study also shows us a great interaction effect! As my past few posts had discussed, we see an interaction because the state “man holding a gun” grants a much faster response than the state of “man holding non-gun.” This interaction is moderated by race! That is, the effect is even more dramatic when the target is Black instead of White. However, we haven’t really spoken much on moderation yet. It’s something that will be discussed soon enough!

So what can we conclude? Given the strong sample size and the replications of this study, it means the stereotypes that we often suppress have a way of influencing our behavior during these really quick decisions. Deciding to shoot, or to hold your fire, would be an incredibly hard decision and these minor influences could mean the different between life and death for the officer or for the suspect.

Clearly, this is an abridged version of the study, and I would be happy to discuss any lingering questions you may have! Please comment and sate your curiosity! Click HERE to see a PDF of the source article if you would like!


Correl, J., Park, B., Judd, C., Wittenbrink, B., Salder, M., & Keessee, T. (2007). Across the thin blue line: police officers and racial bian in the decision to shoot. Interpersonal Relations and Group 



  1. Yannick says:

    Also quite interesting. Reading their general discussion (at least, a part of it) seems their main focus was on showing discrimination in the police force was less active than in the general populace, which they seemed to prove. Certainly discrimination as a whole is still rampant, but I appreciate the original study’s intent – specifically because so many of us have discriminatory views of the police force in general. I realize this is a bit off what the subject matter was, but found it intriguing.

    • They were able to show the police are less affected by this phenomena, but for many social psychologists it means something different.

      -Despite all their training and expertise, they are still subject to this effect. Granted, their experience serves to moderate the effect.

      At the end of the day, the police are members of the community just as everyone else. They are exposed to the same social pressures and social conditioning that we all are. It’s good to see they are more tempered with their experiences, but it goes to show the real danger of allowing cultural stereotypes to run wild like they have for so long.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: