Abstract 

Excerpted From: Seth D. DuCharme, The Search for Reasonableness in Use-of-Force Cases: Understanding the Effects of Stress on Perception and Performance, 70 Fordham Law Review 2515 (May, 2002) (366 Footnotes) (Full Document)

The man lunges from the shadows, his face contorted in anger. His eyes lock with yours as he moves closer. His motion appears strange, as if he is an image on a movie screen and the projector is off speed. The background appears out of focus. The sights and sounds of the world around you change abruptly, supplanted by the sensation of your pounding heart. Your hands tremble. Time seems to slow down. What you do in the next instant could mean the difference between life and death.

Individuals who respond forcibly to such confrontations may face the additional trauma of potential criminal and civil liability. In self-defense and police use-of-force cases, liability turns on whether the individual's response is legally justified. The issue of justification arises in incidents ranging from street fights to police excessive force to domestic violence cases. Each of these areas occupy the courts' dockets, and society's attention. When parties in such cases are brought before a judge or jury, their actions are analyzed by some version of what is commonly known as the “reasonable person” standard. Determining what is or is not reasonable in a violent confrontation, however, is a challenging endeavor.

Scientific studies show that high levels of stress dramatically affect an individual's sensory perception and physical performance. Consultants and expert witnesses can help develop case strategies that take into account perceptual distortions and performance limitations bearing directly on the question of a defendant's reasonableness. While legal and practical obstacles exist, expert testimony can be crucial in effectively presenting a defense of justification or excuse. When a jury is called on to judge the actions of a defendant in a use-of-force scenario, objective, scientific evidence can provide illuminating insight into the factors that affected the defendant's conduct and may be invaluable in accurately assessing whether such conduct was reasonable under the law.

Use of such evidence is currently the exception rather than the rule, however, and the relevant experts, consultants, and scientific studies may be unknown to most lawyers. By looking to the related fields of psychology, neurology, ophthalmology, and motor-skills training, this Note will address the dynamics in use-of-force incidents and suggest ways in which lawyers litigating use-of-force cases can use consultants and experts to bring this information to the jury. Furthermore, this Note will argue that understanding perceptual and performance factors is essential to a better understanding of culpability in use-of-force cases.

Part I of this Note explains the legal standards and concepts relevant to three common types of use-of-force cases, with an emphasis on federal and New York law. First, Part I addresses the law concerning a citizen's use of force in self-defense. Second, this part explains some of the special issues that arise when the use of force in question was by police officers. Third, Part I recognizes some of the unique challenges for courts and juries in determining reasonableness in cases of domestic violence. Finally, Part I explains the general legal standards for the admissibility of expert witness testimony. II explains the science behind perceptual, cognitive, and physical functioning in what psychologists refer to as “high arousal” states. By looking to psychological studies on survivors of deadly force encounters, research into perception and cognition and developments in the field of motor-skills training, this part offers a practical perspective on the reasonableness tests and analytic models presented in Part I. Part II suggests that correctly applying the “reasonable belief” standard is much more complicated than the simple statutory language implies.

Part III of this Note presents issues that arise in applying the science to litigation, and addresses situations to which the science is well suited. This part also provides examples of cases where expert testimony and consultation have proven invaluable in assisting litigators. Finally, this part argues that the application of scientific research is critical to fairly and accurately analyzing human behavior in use-of-force incidents, and perhaps all incidents where the parties experience very high levels of stress. . .]

[. . .]

While different types of use-of-force cases involve distinct legal and factual concerns, the common thread that runs through them is the inquiry into the reasonableness of specific conduct under extraordinary circumstances. To justify or mitigate the often unsettling nature of a use of force, a defendant must show that her response was both reasonable and appropriate, whether based on her own belief (subjective inquiry) or on the belief of a reasonable person under the same circumstances (objective inquiry). Under either standard, however, the jury ultimately must judge whether the perceptions, beliefs, and responses in question were proper.

Scientific researchers have developed a body of knowledge that can assist the fact-finder in the determination of reasonableness. To perform a reasonableness analysis absent consideration of the profound effects of stress on perception and performance denies the jury relevant and probative contextual information. At the very least, the lawyer trying the case should be aware of such factors in developing a case strategy. The application of scientific evidence, through available scientific research, consultants, and expert witnesses, can lead to fairer findings in self-defense, police use-of-force, and domestic violence cases. In fact, such evidence may be applicable to all types of cases where critical decisions are made under extreme stress.

J.D. candidate 2003, Fordham University School of Law; former Deputy United States Marshal, Eastern District of New York.