Sleep Deprivation, False Confessions, and Expert Witnesses

Introduction

This paper focuses on the links between sleep deprivation, false confessions, and torture. It is written in the context of Federal Rules of Evidence 702 and the testimony of expert witnesses. The central focus is the contest between experts on each side — defense and prosecution — and how an expert witness can provide clarity regarding a confession and where the line falls on the continuum between a voluntary confession and a statement extracted through torture.

Sleep Deprivation in Interrogation and Its Effects

Sleep Deprivation in the Context of Interrogation

Extreme sleep deprivation is widely used in the context of interrogation and has risen to a fine art. The executive summary of The Senate Intelligence Committee Report on Torture: Committee Study of the Central Intelligence Agency's Detention and Interrogation Program defines "sleep deprivation" as "keeping detainees awake for up to 180 hours, usually standing or in stress positions, at times with their hands shackled above their heads."¹ Sleep deprivation is accomplished through various methods, including loud music — sometimes alternated with loud hissing sounds — extended interrogation periods, renewed interrogation injected just as the subject is about to fall asleep, spraying the interrogatee with cold water, and subjecting the detainee to sustained low temperatures.² In addition, sleep deprivation is often used in concert with slaps, compulsory nudity, and "wallings," which consist of slamming the interrogatee against walls.³ Whether employed alone or in combination with other tactics, international reports indicate that sleep deprivation is a common weapon in an interrogator's arsenal.

Is Sleep Deprivation Torture?

The question of whether sleep deprivation constitutes torture is hotly debated. The United Nations Convention Against Torture defines torture, in relevant part, as any act by which severe pain or suffering, whether physical or mental, is intentionally inflicted on a person for such purposes as obtaining from him or a third person information or a confession — when such pain or suffering is inflicted by or at the instigation of or with the consent or acquiescence of a public official or other person acting in an official capacity. It does not include pain or suffering arising only from, inherent in, or incidental to lawful sanctions.⁴

Furthermore, the Third Geneva Convention prohibits withholding basic necessities such as food, water, and sleep.⁵ Given these two definitions, extreme sleep deprivation would seem to fit squarely within the definition of "torture." Nevertheless, sleep deprivation is not classified as torture under U.S. law. The CIA memo noted that the maximum allowable sleep deprivation is 180 hours, after which the detainee must be allowed to sleep for eight continuous hours,⁶ and another CIA memo asserted that none of the employed methods, including sleep deprivation, violated United Nations sanctions.⁷

Psychological and Physical Effects of Extreme Sleep Deprivation

The majority of experts conclude that most adults require between seven and eight hours of sleep per night.⁸ While sleep requirements vary, the scientific community treats sleep deprivation as a deviation from the amount of sleep to which an individual is accustomed.⁹ Even mildly insufficient sleep can cause sleepiness, clumsiness, and impaired cognitive performance.¹⁰ As sleep deprivation increases in severity, its harmful effects multiply and deepen. While science has found that severe sleep deprivation harms the human body's biochemical and physiological functions, extreme sleep deprivation most seriously affects functions requiring a high degree of cerebral involvement.¹¹

Prior to 2016, behavioral studies had already linked severe sleep deprivation to a wide range of harms: poor regulation of emotions and mood;¹² increased emotional problems;¹³ loss of the brain's "medial prefrontal cortex connectivity,"¹⁴ which in turn causes increased response to negative stimuli in the amygdala — the brain's neurological, integrative center for emotions, emotional behavior, and motivation;¹⁵ and difficulty consolidating negative emotional memories.¹⁶

Though prior studies indicated harms and concerns that might affect the reliability of confessions by sleep-deprived individuals, February 2016 saw the first published scientific study specifically linking severe sleep deprivation to false confessions. Published in Proceedings of the National Academy of Sciences of the United States of America, the study was conducted using eighty-eight university students. Each subject completed a number of computer tasks and a Cognitive Reflection assessment of intelligence during several sessions over the course of a week in psychology professor Kimberly Fenn's Sleep and Learning Lab. While performing the tasks, subjects were repeatedly warned to avoid pressing the "escape" key because "this could cause the computer to lose valuable data."¹⁷

On the last day of the study, half the subjects slept for eight hours while the other half received no sleep overnight. The following morning, each subject was presented with a written statement recapping his or her lab activities and falsely stating that the subject had pressed the "escape" key. Each subject was asked to check a box confirming the statement's accuracy and to sign it. Only eighteen percent of the subjects who had slept eight hours signed the inaccurate statement; however, fifty percent of the sleep-deprived subjects signed it. Furthermore, subjects who scored lower on the Cognitive Reflection test were even more severely affected by sleep deprivation and were far more likely to sign the false confession. The researchers calculated that sleep-deprived subjects were four-and-one-half times more likely to sign the false confession than rested subjects. The researchers found this data troubling, noting that sleep deprivation during police interrogation is common, that as many as seventeen percent of all police interrogations occur between midnight and 8:00 AM, and that as many as fifteen to twenty-five percent of all wrongful convictions in the United States are based on false confessions.¹⁸

Professor Fenn stated: "It's a crucial first step toward understanding the role of sleep deprivation in false confessions and, in turn, raises complex questions about the use of sleep deprivation in the interrogation of innocent and guilty suspects."¹⁹

As one of the study's authors, cognitive psychologist Elizabeth Loftus of the University of California, Irvine, observed: "It's true, this is a far cry from confession to a murder. But we do know we can also get people to confess to things with more serious consequences."²⁰ Concerned by the evident link between sleep deprivation and false confessions, the study's authors concluded: "A false admission of wrongdoing can have disastrous consequences in a legal system already fraught with miscarriages of justice. We are hopeful that our study is the first of many to uncover the sleep-related factors that influence processes related to false confession."²¹ The researchers also recommended that police interrogations be videotaped to give additional insight to attorneys, judges, and jurors regarding an accused's psychological state during interrogation.²²

Legal Standards for Expert Testimony: Frye and Daubert

Groundwork for Exclusion of Coerced Testimony

The U.S. criminal justice system is interwoven with compelling competing interests. The government's interest in securing a confession and conviction is tempered by an individual's right against being compelled to testify against himself²³ or being persuaded to confess due to physical or extreme psychological trauma.²⁴ The fundamental principle is that "ours is an accusatorial and not an inquisitorial system — a system in which the State must establish guilt by evidence independently and freely secured and may not by coercion prove its charge against an accused."²⁵ Consequently, the Supreme Court bans coercive interrogation to garner involuntary confessions,²⁶ allowing the accused to contest the voluntariness of his statements and empowering the court to exclude those statements if they are found to be involuntary.²⁷ Therein lies the groundwork for the admission or exclusion of an accused's confession.

Frye v. United States, 293 F. 1013 (D.C. Cir. 1923)

James Alphonse Frye was a young man arrested in Washington, D.C. in the summer of 1920 for robbery. In November 1920, Robert Wade Brown, a prominent physician and president of the National Life Insurance Company, was shot to death in the front hallway of his Washington, D.C. home. The identity of Brown's killer remained a mystery, and a one-thousand-dollar reward was offered for information leading to the killer. Under police questioning, Frye confessed to killing Brown.

According to the official confession, Frye claimed to have gone to Brown's house for gonorrhea medicine but lacked money to pay. Brown supposedly refused and a struggle ensued, during which Brown was accidentally shot. Frye's confession states, in part: "I tried to run to the door and he grabbed me again and knocked me down and I told him to put his hands up and he kept on hitting me, hitting me on the head, and in the struggle I think that my gun was fired."²⁹ Frye was convicted of the robbery charge and sentenced to four years in prison.

For the murder charge, Frye was represented by the firm of Mattingly & Wood, who attempted to have Frye's confession excluded through expert testimony. The defense retained Dr. William M. Marston, an expert in the use of a sphygmomanometer (a blood-pressure cuff). According to Marston, he could detect deception by examining a subject's systolic blood pressure under questioning. Marston's theory was that truth is effortless while deception takes effort; consequently, blood pressure rising during case-relevant questions indicated effortful deception. Marston administered the examination to Frye in the Washington, D.C. jail, and his results indicated that Frye's confession to killing Brown was deceptive.³⁰

At trial, Mattingly & Wood attempted to introduce Marston's expert testimony and also claimed that Frye had been duped by police and by a dentist named John R. Francis into confessing to Brown's murder by promises of dropped charges, acquittal, and a share of the reward money. The trial judge rejected Marston's testimony and admitted Frye's confession. Frye was convicted of second-degree murder, sentenced to life imprisonment, and transported to Leavenworth.

Mattingly & Wood appealed to the D.C. Circuit Court of Appeals, raising the central issue of whether it was error to refuse admission of testimony from an alleged expert in deception.³¹ The appellate court upheld the trial court's decision, establishing the Frye test for admissibility of expert witness testimony in the process:

"Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone the evidential force of the principle must be recognized, and while the courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs."³²

With that terse decision in Frye v. United States, 293 F. 1013 (D.C. Cir. 1923), the court established a test for determining admissibility of expert testimony according to whether the underlying method is generally accepted by the appropriate scientific community.³³ The Frye standard remained the norm in federal and state courts for approximately seventy years and is still used in numerous state courts today.

Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993)

The petitioners in this case were two children with severe birth defects and their parents. They sued Merrell Dow Pharmaceuticals, Inc. in California state court, alleging that Bendectin — a drug manufactured by Merrell Dow — caused the children's birth defects. After the case was transferred to federal district court, Merrell Dow moved for summary judgment supported by expert affidavit testimony. Merrell Dow's expert, Dr. Steven H. Lamm, a physician and epidemiologist, reviewed all published literature on Bendectin and human birth defects — more than thirty published studies involving over one hundred and thirty thousand patients — and concluded that Bendectin had not been shown to cause human birth defects.³⁴

In opposition, the plaintiffs presented eight expert witnesses who found that the drug could cause severe birth defects, based on: in vitro and in vivo animal studies linking Bendectin to defects; pharmacological studies of the drug's chemical structure showing similarities to known teratogens; and reanalysis of published human statistical studies.

The District Court accepted Merrell Dow's expert evidence but rejected the plaintiffs' expert evidence under the Frye standard, finding that it was prepared specifically for the litigation and lacked general acceptance in the relevant scientific community.³⁵ Summary judgment was granted for Merrell Dow. The Ninth Circuit affirmed.

The plaintiffs then appealed to the United States Supreme Court, arguing that the 1975 adoption of the Federal Rules of Evidence — including Rule 702 — supplanted Frye as the governing standard for admissibility of expert testimony in federal court. The Supreme Court majority agreed, citing the text of the Rules, the absence of any mention of Frye in those Rules, and its prior holding that when common law rules conflict with the Federal Rules of Evidence, the Rules govern.³⁶ The Supreme Court vacated the Ninth Circuit's judgment and remanded for further proceedings.

Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993) thus made Federal Rule of Evidence 702 the superseding standard, allowing the relatively generous admission of expert testimony provided it is adjudged scientifically trustworthy and useful to the trier of fact.³⁷ Daubert was later interpreted to apply to expert testimony from experts with less rigorous scientific backgrounds, such as social scientists.³⁸

Both Frye and Daubert appear deceptively simple. However, they are merely part of the test for expert witness admissibility. In order to admit expert testimony as to the voluntariness of a confession, three thresholds must practically be met. First, the testimony must not be limited to general conclusions about whether an accused might make involuntary confessions under certain circumstances. Second, the proffered expert testimony must pass either the more permissive Daubert or the more stringent Frye test for admissibility. Third, the expert's procedure for arriving at his or her conclusions must be intimately connected to this particular defendant: what were the conditions of the defendant at the time he or she gave the confession?

Conclusion

After considerable research into the natures of torture, legal U.S. police interrogation, sleep deprivation, confessions, and their admissibility or inadmissibility, it is clear that there is no way to draw a meaningful line on the continuum between voluntary and involuntary confessions without close attention to a specific defendant, a specific interrogation session, and a specific case. We can affirm that an individual has compelling constitutionally protected interests against self-incrimination and against admissions coerced through physical or psychological pressure. However, science shows that effective expert testimony — whether for or against a confession's admissibility — entails deep, specific, detailed, and articulately presented knowledge of: the tactics used on the suspect during interrogation and their strength; the specific vulnerabilities of this suspect to one or more of those tactics; the ways in which the tactics can be used to obtain a confession; what occurred during the interrogation that might lead the suspect to believe a confession would be inconsequential or in his or her best interest; whether and how this suspect is vulnerable to any of those occurrences; and the interrelation of the interrogation tactics, the suspect's vulnerability, and the suspect's assessment that a confession would be harmless or self-serving.

The 2016 Fenn study marks a turning point in the empirical understanding of false confessions. As the body of scientific literature grows, the evidentiary standards established in Frye and Daubert provide the legal framework through which courts can evaluate — and expert witnesses can communicate — the degree to which sleep deprivation compromises the voluntariness of a confession. Only with both rigorous science and rigorous legal analysis can the trier of fact hope to distinguish a truly voluntary confession from one extracted by the coercive power of extreme sleep deprivation.