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Neuroscientist; Chairman, Project Reason; Author, Letter to a Christian Nation; Free Will

When evaluating the social cost of deception, one must consider all of the misdeeds—marital infidelities, Ponzi schemes, premeditated murders, terrorist atrocities, genocides, etc.—that are nurtured and shored-up, at every turn, by lies. Viewed in this wider context, deception commends itself, perhaps even above violence, as the principal enemy of human cooperation. Imagine how our world would change if, when the truth really mattered, it became impossible to lie.

The development of mind-reading technology is in its infancy, of course. But reliable lie-detection will be much easier to achieve than accurate mind reading. Whether on not we ever crack the neural code, enabling us to download a person’s private thoughts, memories, and perceptions without distortion, we will almost surely be able to determine, to a moral certainty, whether a person is representing his thoughts, memories, and perceptions honestly in conversation. Compared to many of the other hypothetical breakthroughs put forward in response to this year’s Edge question, the development of a true lie-detector would represent a very modest advance over what is currently possible through neuroimaging. Once this technology arrives, it will change (almost) everything.

The greatest transformation of our society will occur only once lie-detectors become both affordable and unobtrusive. Rather than spirit criminal defendants and hedge-fund managers off to the lab for a disconcerting hour of brain scanning, there may come a time when every courtroom or boardroom will have the requisite technology discretely concealed behind its wood paneling. Thereafter, civilized people would share a common presumption: that wherever important conversations are held, the truthfulness of all participants will be monitored. Well-intentioned people would happily pass between zones of obligatory candor, and these transitions will cease to be remarkable. Just as we’ve come to expect that many public spaces will be free of nudity, sex, loud swearing, and cigarette smoke—and now think nothing of the behavioral changes demanded of us whenever we leave the privacy of our homes—we may come to expect that certain places and occasions will require scrupulous truth-telling. Most of us will no more feel deprived of the freedom lie during a press conference or a job interview than we currently feel deprived of the freedom to remove our pants in a restaurant. Whether or not the technology works as well as we hope, the belief that it generally does work will change our culture profoundly.

In a legal context, some scholars have already begun to worry that reliable lie detection will constitute an infringement of a person’s Fifth Amendment privilege against self-incrimination. But the Fifth Amendment has already succumbed to advances in our technology. The Supreme Court has ruled that defendants can be forced to provide samples of their blood, saliva, and other physical evidence that may incriminate them. In fact, the prohibition against compelled testimony appears to be a relic of a more superstitious time: it was once widely believed that lying under oath would damn a person’s soul for eternity. I doubt whether even many fundamentalist Christians now imagine that an oath sworn on a courtroom Bible has such cosmic significance.

Of course, no technology is ever perfect. Once we have a proper lie-detector in hand, we will suffer the caprice of its positive and negative errors. Needless to say, such errors will raise real ethical and legal concerns. But some rate of error will, in the end, be judged acceptable. Remember that we currently lock people away in prison for decades—or kill them—all the while knowing that some percentage of those convicted must be innocent, while some percentage of those returned to our streets will be dangerous psychopaths guaranteed to re-offend. We have no choice but to rely upon our criminal justice system, despite the fact that judges and juries are poorly calibrated truth detectors, prone to error. Anything that can improve the performance of this ancient system, even slightly, will raise the quotient of justice in our world.

There are several reasons to doubt whether any of our current modalities of neuroimaging, like fMRI, will yield a practical form of mind-reading technology. It is also true that the physics of neuroimaging may grant only so much scope to human ingenuity. It is possible, therefore, that an era of cheap, covert lie-detection might never dawn, and we will be forced to rely upon some relentlessly costly, cumbersome technology. Even so, I think it safe to say that the time is not far off when lying, on the weightiest matters, will become a practical impossibility. This fact will be widely publicized, of course, and the relevant technology will be expected to be in place, or accessible, whenever the stakes are high. This very assurance, rather than the incessant use of these machines, will make all the difference.