(Joe Raedle/Getty Images)

In the next few weeks, a grand jury will decide whether to indict the police officer who shot and killed Michael Brown this summer in Ferguson, Mo. Whatever the decision, Brown’s death, and the subsequent protests it engendered, has raised fresh concerns about racial disparities between residents and the police forces that patrol them. In Ferguson, approximately two-thirds of the people are black but the police force is over 90 percent white.

Should such statistics make us uneasy?  The answer depends on two questions.  Does officer representativeness affect how communities perceive police? And do minority police understand their jobs and behave differently than white police?  The answer to both questions is: yes.

In fact, whether public servants “look like” the citizens they serve affects citizens in many ways. For example, minority students, in schools with greater numbers of minority teachers, perform far better than those in schools with fewer such teachers. And minority students in schools with more minority teachers may be less likely to get pregnant than those in schools with fewer minority teachers.

The representativeness of police forces also appears to matter. Blacks are more likely to perceive interactions with police as legitimate if there are black officers present. Similarly, people’s perceptions of how police handle instances of domestic violence are affected by the genders of the police officers who respond to them.

But do minority police, once they go behind the “blue wall of silence,” think and act differently than white police? The police department is thought to have a strong effect on all who enter it. One police chief famously noted that: “The day the new recruit walks through the doors of the police academy he leaves society behind him to enter a profession that does more than give him a job, it defines who he is.” Other accounts echo this, noting that police cultures mold entrants with “numbing regularity.” Even if minority police hope to do things differently, they may find themselves conforming to the expectations of departments that are typically majority white.

But there is a problem with this perspective: there have been few rigorous studies that chart how police cadets actually develop. In my new book, I tracked a cohort of entering police in a large east coast city for the first two years of their careers. Although all entrants shifted their views somewhat, I found that claims about police departments “defining” their officers are overhyped: most officers remained firmly attached to their preexisting motivations, identities, and perceptions.

In particular, I found that minority police, even after entering a department in which whites were the majority, perceived their work differently. They were more likely to see the problems like poverty and criminality as resulting from circumstance, whereas white police were more likely to cite choice or moral character. And despite similarities in training, minority officers were less likely to agree that the use of force was effective for keeping the peace.

Although my study tracked these officers for only two years, it suggests that minority police, even after many years on the force, may continue to see their work differently than white police.

Ultimately, it is impossible to know how a minority officer would have reacted to the altercation with Michael Brown on the night he was shot. Nonetheless, the evidence here suggests that it’s important for police departments to match the demographics of the citizens they police. Creating more representative police forces may enhance citizens’ perceptions of the fairness of police behavior and, perhaps more importantly, alter when and where officers use force.

Zachary Oberfield teaches political science at Haverford College. His recent book is titled: “Becoming Bureaucrats: Socialization at the Front Lines of Government Service.”