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