The United States Commission on Civil Rights invited Professor David A. Harris of the University of Pittsburgh School of Law to testify at the Commission’s hearing on October 17, 2014. The subject of the hearing is Stand Your Ground laws. The state of Florida passed the first such law in 2005, and many states have followed suit. Professor Harris will testify about how these laws are influenced by unconscious, implicit racial bias. The following is the written version of Professor Harris’s testimony.



Written testimony of David A. Harris Distinguished Faculty Scholar and Professor of Law

University of Pittsburgh Stand Your Ground Laws and Implicit Bias United States Commission on Civil Rights

October 17, 2014, Orlando, Florida



I am grateful to the Commission for the invitation to share my views on the subject of Stand Your Ground (SYG) laws. These laws now exist in the majority of the States, and they have had a measurable impact on deadly violence and the criminal justice systems in many of them. I will begin with a basic explanation of what these laws say, especially how they differ from the long-established law of self-defense in Anglo-American law. I will then examine the empirical evidence concerning how SYG laws work; this evidence has emerged in just the last couple of years. I will then discuss implicit bias, which is the source considerable racial disparity in the enforcement of SYG laws, and the rest of the criminal justice system.

I. A Brief Examination of SYG Laws

For centuries, the Anglo-American law on homicide and self-defense have remained the same. Statutes against homicides prohibit unlawful killings, but the law against homicide has always allowed for self-defense. A person under attack with deadly force may respond in kind. A person suffering unlawful aggression may respond with the amount of force that is reasonably necessary to protect herself. The law has always said that a killing in self-defense does not constitute criminal homicide, as long as the person defending herself had a reasonable belief that her life was in imminent danger.

From its earliest times, the law of self-defense has included an important exception. When one under attack knows he can escape from danger by retreating, without risking further danger to herself, he must retreat. Like the law against homicide, the rule of retreat attempts to avoid unnecessary death – even the death of an unlawful attacker – unless the circumstances present no alternative. The rule of retreat is itself subject to an exception: the rule has almways applied everywhere except in the home of the person under attack. This exception to the rule of retreat, known as the castle doctrine, makes sense: the home is the last and final place to which one could retreat. Thus a victim never had to retreat from an attacker in her own home; she could stand and fight back.

SYG laws change this ancient legal landscape in a fundamental way. SYG laws abolish the rule of retreat in any place the person defending herself has a right to be. Put another way, SYG laws take the rule of retreat from the home and extend it into public places. A person under unjustified attack in a public place need not retreat, even if she knows she can get away in complete safety; she can stand her ground, and even use deadly force if she faces deadly force. With an SYG law, one who kills under a claim of self-defense would not have to prove that she had no means of escape. Instead, she need only show that she had a reasonable fear of death or deadly injury, and that the incident occurred in a public place in which she was lawfully present.

This “no retreat in public” idea is the central feature of Florida’s SYG law. The Florida law also gives criminal and civil immunity to one claiming an SYG defense. When the killer makes an SYG claim, police cannot immediately arrest, detain, charge or prosecute, as they usually would. Police and prosecutors may investigate, utilizing “standard procedures,” but they cannot arrest unless the agency “determines that there is probable cause that the force that was used was unlawful.” Should the police or prosecutors choose to pursue charges anyway, the person is entitled to a pretrial hearing in which a judge decides whether the defendant should have received SYG immunity.

Florida’s SYG law, enacted in 2005, led to many new SYG laws across the United States. According to Professor Tamara Lawson of St. Thomas University School of Law, as of 2014, thirty-four states had SYG provisions that eliminated the duty to retreat in public places. Legislatures created the SYG provisions twenty-five states; court decisions created them in the other nine states. (These numbers do not include states that only have a no retreat rule in the home, since that is the traditional rule replaced by SYG.)

II. How Do SYG Laws Work in Practice?

Proponents of SYG laws said that significant changes would follow enactment of these laws. Crime would decrease, including violent crime and homicides, because criminals would know that victims could meet deadly force with deadly force. The net effect would be less crime and deadly violence, especially killings.

Because almost ten years have passed since the enactment of Florida’s 2005 SYG law, researchers now have data that has enabled them to study the effects of these laws. These empirical evaluations cast doubt on the assumptions of SYG advocates about crime and violence. The first thing researchers have tested empirically focuses on the central promise of SYG laws: they will make us safer from serious crime, especially homicide. In their paper “Does Strengthening Self-Defense Law Deter Crime or Escalate Violence? Evidence from the Castle Doctrine,” Texas A&M University researchers Cheng Cheng and Mark Hoekstra examined data on crime and homicide patterns from 2000 to 2010. They compared rates of violent crime and homicide before and after passage of the SYG laws, and they also compared data from other states that did not pass SYG laws. From these data, Cheng and Hoekstra made comparisons of SYG states and non-SYG states, both before and after passage of these laws; they also compared states in the same geographic regions. The results did not show what proponents of SYG laws had predicted. Concerning violent crimes – burglary, robbery, and aggravated assault – Cheng and Hoekstra found that SYG laws had no effect. The authors found “no evidence of deterrence effects” for any of these crimes. However, the frequency of one crime did change. In SYG states, more homicides occurred after the passage of these laws than had occurred before. SYG laws, the authors said, “increase homicides by a statistically significant 8 percent,” which yields 600 more homicides per year across all states with SYG laws. These results – not greater safety, but an eight percent increase in unlawful killings – seem to show that those who believed that SYG laws would decrease violent crime were wrong.

Another 2012 paper, by Chandler McClellan and Erdal Tekin of Georgia State University independently produced similar results. Using a different data source and a different methodology than Cheng and Hoekstra, McClellan and Tekin concluded that “Stand Your Ground laws are associated with a significant increase in homicides. . . .” They say their results “are robust to a number of specifications and unlikely to be driven entirely by the killings of assailants.” Their findings “raise serious doubts against the argument that Stand Your Ground laws make America safer.”

Other empirical work on SYG laws also reveals that SYG laws have a disparate racial impact. In his study “Race, Justifiable Homicide, and Stand Your Ground Laws: Analysis of FBI Supplementary Homicide Report Data,” John K. Roman of the Justice Policy Center of the Urban Institute studied SYG data to determine whether “justifiable homicides differ by the race of the victim and offender” and whether certain “fact patterns of homicides increase racial disparities.” Roman aimed to “analyze objective national data that could measure the presence of racial disparities in rulings of justifiable homicides.” Roman’s work demonstrated, first, that SYG states “have statistically significantly higher rates of justifiable homicide than non-SYG states.” Second, including race in the analysis revealed shocking patterns. Roman writes that, when a state has a SYG law, “controlling for all other attributes, the odds a white on black homicide is found justified is 281 percent greater than the odds a white on black homicide is found justified.” And for cases that exhibit particular fact pattern, SYG laws “worsen the disparity.” Roman says that when the facts in a case show 1) a single victim; 2) a single shooter; 3) a male victim and a male shooter; 4) a victim and a shooter who are strangers to each other; and 5) the use of a gun, states with SYG laws show increased disparities between cases in which a white kills a black victim, and cases in which a black kills a white victim.

Thus SYG laws have increased deadly violence, and they have had a distinct racial impact. If racial effects emerge when we examine killings taking place SYG laws, we need to ask why this occurs. Are those who shoot under SYG laws racist bigots? Or is there a deeper explanation?

III. Implicit Bias: How It Operates and Its Impact

For most of us, allegations that a particular person has engaged in racist behavior would cause us to look for specific types of racist conduct: perhaps the use of racial epithets, or statements like “I’d like to hire _______ (fill in the name of a racial or ethnic group under discussion) but I can’t – they just aren’t responsible or smart enough.” Certainly, some people hold such attitudes; perhaps in some social contexts, they may say these things or act on these beliefs. But the problem of racialized attitudes in American society is larger than old-school bigotry – and far more subtle. The racism we see today rarely appears in these obvious ways. Rather, the problem is unconscious racism: in the words of the psychology literature, implicit bias.

Most Americans believe strongly in equality and fairness. According to these beliefs, everyone deserves equal treatment, because we are all entitled to justice and fair dealing from others, and from the government. But empirical studies have proven the existence of a different, hidden reality in our minds. Almost everyone carries an intricate web of unconscious biases, preferring some groups and disfavoring others. These biases may directly contradict our conscious beliefs. And even though we do not know that these implicit biases are there, they may actually override our conscious beliefs about race. Because of this, we may act negatively toward minorities without knowing it is occurring.

The best-known proof of implicit bias comes from the implicit association test, or IAT. Anyone can take the IAT online, and millions have. The IAT measures the speed of mental associations between racially-identifiable partial photographs of faces (the lowest part of the forehead, the eyes, the nose, and the space between the nose and mouth), and positive or negative words. In the first parts of the test, the viewer hits a computer key to associate a white face with a positive word (e.g., good, flower, smile) or a black face with a negative word (bad, hostile, fight). In the next part, the instructions are reversed: the viewer hits the key when she sees a white face with a negative word, or a black face with a positive word. As the viewer performs these tasks, the computer measures the speed with which the viewer hits the key, down to tiny fractions of seconds. The computer then compares the reaction speed of the viewer on tasks congruent with stereotypes (associating white faces with positive words, or associating black faces with negative words) with the reaction speed for tasks not congruent with stereotypes (associating black faces with positive words, or associating white faces with negative words). Regardless of conscious egalitarian values, most viewers react more rapidly when associating white faces with positive words than negative words; they also respond faster when associating black faces with negative words than positive ones. The researchers called these differences implicit biases. Implicit biases favoring whites show up in seventy-five percent of all of the 14 million persons who had taken the test through 2013, including almost forty percent of black test takers. In all of those who showed implicit bias for whites and against blacks, these biases may impact their thoughts and actions. Just as important, they do not know these biases exist.

When implicit biases combine with heuristics, racialized thinking and action may occur. Nobel Prize winning psychologists Amos Tversky and Daniel Kahneman described heuristics as rules of thumb people use to transform complex decisions in information-scarce environments into easier, nearly automatic analyses. People use heuristics unconsciously and rapidly; they give us rapid and efficient ways of making decisions. Heuristics often help us get things right; “frequently accurate,” they move us toward good decisions without consuming a lot of “valuable cognitive resources.” But because people resort to heuristics when faced with thorny choices and a lack of time to gather information, they also “produce systemic errors of judgment that predictably recur in certain situations. . . .” People have little or no conscious control these heuristic-based biases; indeed, they do not even know the heuristics are operating. Our conscious minds can override heuristics, but in most situations, we use them unquestioningly – indeed, without even knowing that we are doing this. This means heuristic-based errors are “difficult to eliminate or even recognize.” Human beings can live with some of this. But when heuristics concern race and suspicion of criminality or violence, negative results may follow.

Implicit biases linking blacks with negative concepts in the minds of the great majority of people gives rise to a particular heuristic: the association of blacks with crime and danger. Phillip Atiba Goff and his co-author L. Song Richardson call the rule of thumb that associates blacks with crime and danger “the suspicion heuristic.” People in an uncertain situation may have difficulty predicting when they might face danger or violence, especially when encountering someone unknown. Walking down a city street at night, toward an unknown person, allows precious little time to gather and process facts or evidence. To deal with this, people “will make their judgments of [potential] criminality quickly, based on small slices of behavior, under highly stressful circumstances.” The suspicion heuristic begins to operate immediately and unconsciously; implicit negative associations with blacks become active.

This research squares with extensive evidence demonstrating how society equates blacks with violent street crime; our mental images – that is, stereotypes – feature blacks as criminals. For example, in Brit Duncan’s work, subjects saw mildly aggressive behavior by an African American person as more threatening than the identical behavior by whites. Research by H. Andrew Sagar and Janet Ward Schofield of the University of Pittsburgh buttressed Duncan’s findings. Sagar and Schofield gave subjects drawings and verbal accounts of two-person interactions – for example, two boys bumping into each other. The subjects rated the actor in the scenario as meaner and more threatening if the actor was African American than if the actor was white. This perception was the same for both African American and white subjects.

The suspicion heuristic and our implicit bias therefore slant the judgments people make when they encounter blacks. This happens unconsciously, without the knowledge that it is occurring, and even if people encountering blacks hold conscious egalitarian beliefs. Whites, and even some blacks, will tend to think of black people they encounter as potential criminals who pose a danger. Worse, the unconscious use of the suspicion heuristic can lead beyond thoughts, to actions. According to Goff and Richardson, the suspicion heuristic can “influence behaviors as well” as perceptions, and “can result in people acting more aggressively than they might otherwise,” all “without any conscious awareness that one is behaving this way.”

The combined potential impact of implicit bias against blacks and the suspicion heuristic on the use of SYG laws is potentially catastrophic. SYG laws lower the potential cost of engaging in deadly violence; one can use deadly force in any public place, even when avoiding violence is possible, and still use the SYG defense to argue that the jury should not convict. Implicit bias against blacks, especially seeing blacks as likely to be violent or dangerous, increases the likelihood that people with weapons will shoot them; armed people are more likely to feel fear, and therefore to shoot. And when the victim is black, members of juries – also infected with the same implicit bias – are more likely to sympathize with the shooter.

Thank you for the opportunity to address the Commission.