ISU psychology professors Zlatan Krizan and Christian Meissner and psychology graduate student Anthony Miller interviewed sleep-restricted and well-rested individuals about past criminal activity, comparing the quantity and quality of their responses. Published in the academic journal SLEEP, their results indicated that sleep-restricted participants provided 7 percent less information about the crime in terms of who, what, when, why, where or how.
“People who had less sleep were not as motivated to recall information or found doing so required more effort to recall information,” Meissner wrote. “These patterns suggest that increased fatigue due to sleep loss may be an important factor in disclosure.”
Krizan said these findings are significant for suspect interrogations and interviews investigators conduct with victims and witnesses to crimes. The researchers found that sleep loss also hampered the quality or precision of information interviewees offered, though their findings weren’t statistically significant.
Additional findings indicate lack of sleep undercuts motivation, making it more difficult for interviewees to remember details.
As a tactic to compel disclosure or suspect confessions, sleep disruption has long been connected to criminal investigations. Although evidence has identified officer-imposed sleep disruption as a “cruel and unusual punishment,” illustrated the danger of sleep deprivation on police performanceand linked sleep loss to false confessions, the ISU researchers said their study is the first to explore “how sleep shapes intelligence disclosures during investigative interviews.”
“Historical and journalistic accounts reveal persistent and ongoing use of sleep deprivation as a means of ‘breaking the resistance’ of uncooperative interrogation participants,” the researchers wrote.
“Even when not imposed on detainees, sleep disruption is endemic to custodial environments across military and law-enforcement sectors.”
To replicate the conditions of a criminal investigation — during which suspects, victims and witnesses are often fatigued or functioning on little sleep when interviewed — researchers randomly assigned the 143 participants to a sleep-restricted or control group. Those in the sleep-restricted group went to bed two hours later than normal and woke up two hours earlier, eliminating eight sleeping hours over two days.
Interviewers asked participants in both groups to disclose past criminal activity based on a list of 20 crimes, among them transporting fireworks, trespassing, shoplifting and driving under the influence. When questioned about their most severe crime, participants in the sleep-restricted group failed to recall information more often than the control group.
Across 10 interviews (a figure often necessary in homicide investigations), participants who lost five hours of sleep together provided around five fewer verifiable details about the crime than control group participants.
Though significant, the study has several limitations. For one, researchers didn’t truly reach their target sample, because neither the sleep-deprived nor control group participants faced legal consequences for their confessions. Still, the “feelings of guilt or shame they likely experienced” represent a “barrier to disclosures” that people involved in real criminal investigations face.
But unlike the professionals or trained law enforcement officers who interview actual suspects, witnesses and victims, the interviewers in this study were of “relatively low” “power and status,” necessitating further research into power differences, sleep deprivation and their intersections.
Citing the trauma suspects, witnesses and victims endure, as well as their attempts to escape authority, the researchers called sleep loss “a substantive and persistent influence on the amount of information that investigators collect,” urging criminal investigators to “consider the sleep history of their interview participants.”
Since interrogators often have to wake suspects in custody to interview them, they should also consider how grogginess upon waking impacts disclosure.
“While immediate debriefing or interrogation is advised in many cases (because the participant may be unavailable later, because social influence may contaminate memory, or because others may dissuade participants from reporting), delaying interviews may be advised in certain circumstances to off-load any sleep pressure and aid memory or effort investment,” the researchers wrote.
The full study is available here.""
The entire story can be read at:
https://thecrimereport.org/2021/06/29/sleep-deprived-suspects-struggle-in-criminal-interrogations/
