Donald Trump said that “enhanced interrogation … works.” But scientists have shown that the stress and pain induced by techniques like waterboarding can impair memory, and, therefore, inhibit a person from recalling information.
Enhanced interrogation can entail techniques such as slapping a person in the face, sleep deprivation, cramped confinement and waterboarding — the last of which involves reducing airflow with water to trigger the feeling of drowning.
This isn’t the first time Trump, the Republican presidential nominee, has claimed enhanced interrogation works. Back in February, he said:
Trump, Feb. 17: Torture works. OK, folks? You know, I have these guys—”Torture doesn’t work!”—believe me, it works. And waterboarding is your minor form. Some people say it’s not actually torture. Let’s assume it is. But they asked me the question: What do you think of waterboarding? Absolutely fine. But we should go much stronger than waterboarding.
More recently in a July 27 press conference, Trump doubled down on his claim and said, “I am a person that believes in enhanced interrogation, yes. And by the way, it works.”
But research in neuroscience and psychology suggests otherwise. In a 2009 Trends in Cognitive Sciences review paper, Shane O’Mara, a brain researcher at Trinity College Dublin in Ireland, wrote, “The use of [enhanced interrogation] techniques appears motivated by a folk psychology that is demonstrably incorrect.”
What is that folk psychology? O’Mara describes it as “the idea that repeatedly inducing shock, stress, anxiety, disorientation and lack of control is more effective than are standard interrogatory techniques in making suspects reveal information.”
It is also assumed that this information is “reliable and veridical, as suspects will be motivated to end the interrogation by revealing this information from long-term memory,” O’Mara says. But this idea is “unsupported by scientific evidence,” he adds.
O’Mara goes on to say that “[s]olid scientific evidence of how repeated and extreme stress and pain affect memory and executive functions (such as planning or forming intentions) suggests that these techniques are unlikely to do anything other than the opposite of that intended by coercive or ‘enhanced’ interrogation.”
So what does the scientific literature say on the matter? In his review, O’Mara looked at research on how increased stress affects brain regions and mechanisms involved in memory function.
To start, while many brain functions remain elusive to neuroscientists and psychologists, memory formation and recall relies, in part, on a relatively well-understood mechanism — long-term synaptic potentiation, or LTP.
Scientists have investigated this mechanism through anatomical dissection and brain imaging, among other techniques, in both lab animals and humans since the 1970s. In particular, researchers have found that this mechanism is disrupted by extreme and prolonged stress and pain, explains O’Mara. Studies on rats and mice dating back to 1987 support this conclusion.
O’Mara also explains that the hippocampus and prefrontal cortices, regions of the brain, are both “essential for normal memory function.” These regions of the brain are involved in LTP. When an individual is stressed, especially for long periods, these brain regions become compromised.
How? Stress causes the release of hormones like cortisol, which impair the function in these brain regions, sometimes even resulting in tissue loss, explains O’Mara. And when these regions are compromised, people have trouble recalling both short- and long-term memories. “[P]rolonged and sustained sleep deprivation, in part because it results in a substantial increase in cortisol levels, has a deleterious effect on memory,” he says.
For example, in a 2009 paper published in Nature Reviews Neuroscience, which O’Mara cites, Amy F. T. Arnsten, an expert at Yale in both neuroscience and psychology, reviewed both human and animal studies that looked at the effect of stress on the prefrontal cortex.
Arnsten writes that studies have found, “Even quite mild acute uncontrollable stress can cause a rapid and dramatic loss of prefrontal cognitive abilities, and more prolonged stress exposure” can permanently change the structure of the region for the worse.
It may also be difficult to “determine during interrogation whether the information that a suspect reveals is true,” argues O’Mara. Why? Information “presented by the captor to elicit responses during interrogation might inadvertently become part of the suspect’s memory, especially because suspects are under extreme stress and are required to tell and retell the same events that might have happened over a period of years.”
His argument relies on the science behind confabulation, or the production of false memories, as it’s “a common consequence of frontal lobe disorders,” explains O’Mara. And as already noted, prolonged and extreme stress has a negative effect on this brain region’s function and structure. Thus, he says, “distinguishing between confabulations and what is true in the verbal statements of tortured suspects will be difficult.”
O’Mara also cites studies that looked at the function of the frontal lobes in individuals with post traumatic stress disorder. “Brain imaging in people previously subjected to severe torture suggests that abnormal patterns of activation are present in the frontal and temporal lobes … leading to deficits in verbal memory for the recall of traumatic events,” O’Mara writes.
O’Mara concludes his paper stating that “coercive interrogations involving extreme stress are unlikely to facilitate the release of veridical information from long-term memory, given our current cognitive neurobiological knowledge.” On the contrary, he adds, “these techniques cause severe, repeated and prolonged stress, which compromises brain tissue supporting memory and executive function.”
To top it off, a report on the matter from the Senate Select Committee on Intelligence said: “The CIA’s use of its enhanced interrogation techniques was not an effective means of acquiring intelligence or gaining cooperation from detainees.” The report, released in 2014, adds, “The CIA’s justification for the use of its enhanced interrogation techniques rested on inaccurate claims of their effectiveness.”
In sum, while Trump says that enhanced interrogation “works,” scientific evidence from neuroscience and psychology — and the Senate intelligence committee — says that it doesn’t.
Correction, Aug. 1: We originally wrote that a 2012 Central Intelligence Agency report made conclusions about the CIA’s use of enhanced interrogation, but it was a Senate Select Committee on Intelligence report released in 2014. We corrected the article accordingly.
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