This post is the latest installment of our “Monday Reflections” feature, in which a different Just Security editor examines the big stories from the previous week or looks ahead to key developments on the horizon.

Last week, a new batch of declassified documents released in Freedom of Information Act litigation again graphically chronicled the “enhanced interrogation techniques” used in the wake of 9/11. These documents remind us yet again of a central fallacy shared by too many participants in the Great Torture Debate: the assumption that torture works. That assumption — magnified by endless Hollywood depictions — has led them to an instrumental, consequentialist conclusion: If we face the existential threat of a “ticking time bomb,” at some point, law and morals must give way. But the logically prior question in this debate has always been scientific, not political, legal, or ethical. Does torture work, or does it fatally impair the physical capability of the person being tortured to provide reliable information? If so, why bother?

For ethical reasons, until now we have had few scientific studies of whether and how torture works. The assumption justifying torture has been that victims will ultimately comply with an interrogator’s demands once they have been psychologically “broken.” But in Why Torture Doesn’t Work, Shane O’Mara of Trinity College, Dublin — a leading researcher on experimental brain function — meticulously works his way through extensive neuroscience literature and reaches the opposite finding. He details why torture fails at the cellular level: “for reasons that are grounded in what we know about what happens within the brain as the result of the imposition of the chronic, severe, and extreme stressor states used in torture” (p. 3). In fact, he finds, every specific tactic used to extract information by torture — sleep deprivation, temperature changes, waterboarding, food restriction — inhibits rather than enhances the victim’s ability truthfully to recall memories. “The imposition of severe stressor states,” O’Mara concludes, “has the unintended and unwanted consequence of also affecting the very fabric of mood, memory, and thought in their brains” (p. 247). By destroying mood, mind, and memory, torture tactics physically incapacitate victims from recalling or delivering any reliable account of whatever information they may withhold.

O’Mara’s measured scientific account shatters urban legend, Hollywood fantasy, and Beltway boast. Take, for example, presidential candidate Donald Trump’s pledge to restore “worse than waterboarding” for suspected terrorists. What would that actually accomplish? Waterboarding, O’Mara shows, causes certain “loss of blood flow to th[e] rostral areas of the brain [that] will impair function in these areas for many tens of seconds and perhaps minutes or more” (p. 183). Survivors of near-drowning exhibit “severe cognitive difficulties across all test domains” (pp. 184–85).

When you are being tortured, the stressors imposed cause your brain to slow, then to shut down so as to become incapable of accurately retrieving information and conveying it coherently to others. So a suspect being tortured will not accurately identify where a ticking time bomb is because they will neither recall nor answer truthfully. Indeed, given how torture physically affects the body and brain, they likely will not speak at all until long after any bomb might have already exploded. Did Khalid Sheikh Mohammed’s repeated waterboarding actually lead to us finding bin Laden, as Zero Dark Thirty implied? Again, plainly no. The information revealed was totally false, and what eventually led to bin Laden’s doorstep was ignoring it, not following it (pp. 101–02).

The ultimate irony of “enhanced interrogation tactics,” O’Mara argues, is that every one of “the techniques that are supposed to ‘enhance’ interrogation [achieved] precisely the opposite—they impair interrogation” (p. 247). This micro-failure led to an inevitable cascade of macro-failures. Torture “fail[ed] completely on its own terms. It fails in the intelligence outcomes sought but lost, the pathologies of psychological function it causes, the corruption of good investigative and humane interrogative practice it induces, the corrosion of institutions and democracies it causes, the lives it ruins” (p. 3). And in the end torture changes most not the tortured, but the torturer. The most chilling part of O’Mara’s analysis (pp. 204–39) explains how a man who helped torture Khalid Sheikh Mohammed reportedly said, “When you cross over that line of darkness, it’s hard to come back. You lose your soul.” Or in the words of one Guantánamo torturer, “[t]hose who corrupt others corrupt themselves in the process” (p. 222).

But if torture doesn’t work, why do people keep insisting on torturing? Because they are ordered to do so. And why would anyone ever approve such a self-defeating tactic? Because they are misled. Torturers persist in the illusion that they protect, when in fact, they punish without due process, impose retribution, express society’s rage, and carry out the posturing of politicians. Torture becomes not the means, but the end. As Orwell observed, “the object of torture is torture.”

At the end of the day, O’Mara’s volume leaves one with more than a little sense of shame. Why did we not know this science? If torturing achieves only the deliberate violation and degradation of another human parading as a search for intelligence, how could we have spent the last 15 years debating an irrelevant question. “Should we torture?” is as meaningless a moral or ethical question as “Should we shoot fish in a barrel or beat dead horses?” Such pointless, abusive practices have only costs, not benefits, for both the practitioners and the victims.

O’Mara’s careful parsing of neuroscience insists that going forward, we must permanently shift our debate to a different question. Not “should we torture?” but “accepting the science that torture doesn’t work, how can authorities lawfully and morally obtain truthful information from hostile witnesses?” In his most important chapter (“Why Not Talk?”) O’Mara offers this cardinal principle: “during an interrogation, the desire to punish the detainee conflicts very directly with the signal importance of extracting information from the memory system of the individual who is being interrogated” (p. 259). In an acknowledged time of terror, what is the most effective, lawful way to get accurate information to prevent attacks? O’Mara’s tentative answer:

[A]s a matter of normal good practice, detainees should be treated with the maximum amount of respect, not exposed to deliberate or degrading treatment, and permitted, within the demands of security, to exercise some degree of choice or control over the conditions of their capacity with respect to nourishment, freedom of association, exercise, and cognitive stimulation (including access to reading and writing materials). … The cultural practices surrounding interrogation should become one of shared problem solving—changing the expectations of the detainees so that they become participants in the process, rather than attempting to resist the process. (pp. 259–61)

After hearing this, one critic caustically wrote O’Mara: “Maybe you would prefer it that we give them a mocha latte and ask them to play nice with others” (p. 243). But in fact, some of these better practices now apparently guide the work of High-Value Detention Interrogation Group (HIG), formed by the Obama administration to gather intelligence in non-coercive ways after August 2009. And too little celebrated in Hillary Clinton’s recent national security speech at Stanford was this sober statement: “Another thing we know that does not work, based on lots of empirical evidence, is torture. Many intelligence, military and law enforcement experts have attested to this fact.” We should now add neuroscientists to this list.

Editor’s note: This post is based on a forthcoming review in Political Psychology of Shane O’Mara, Why Torture Doesn’t Work: The Neuroscience of Interrogation, Harvard University Press, 2015.