Lying seems to be the topic of the day. In the last month alone two popular articles have appeared covering recent attempts to unveil the brain signatures of lying. The first came out in the January issue of Wired. (You may find the electronic version here.) And today the NY Times Magazine follow up with their take on the story. Go read it here.
Both articles basically report the same story. Aftet 9/11 the American government has become highly interested in procuring a sure-fire method of spotting liers. The American military has a whole department, the Department of Defense Polygraph Institute (DODpi), working exclusively on inventing an easy-to-use device that in the future will be able to tell apart lies from the truth. Clearly such a device will have to be based on the ability to identify physical tell-tale signs that a person is lying. And to do so, DODpi will have to know the neural cause of lying. Reportedly more than 50 American labs are currently working on identifying these brain processes.
Not much, however, is known about the neurocognitive mechanisms underlying lying. Chances are that lying cannot be associated with just one “lie-module”. When lying you must be able to distinguish the lie from the truth; you will probably have to activate your ToM-system in order to organize your lie in accordance with what you think the other person knows and wants to hear; in some situations you have to remember what you have previously told other persons; you certainly have to plan ahead; and most probably you will have to control your emotional system. These cognitive mechanisms all rely on numerous neural processes.
So, what to do about structures that show up on statistical parametric maps in fMRI experiments? Dan Langleben – the first researcher to study lying with fMRI – have demonstrated that making a lie is associated with elevated activity in the anterior cingulate cortex. Yet, as I have previously noted in a post on this blog, the precise function of the ACC is still unclear. Thus, it may be the case that even though lying is associated with ACC activity, not all activity in the ACC is associated with lying! This opacity of the brain raises serious ethical questions, because will a DODpi-device made to detect ACC activity label some people liars who are not really lying? And will it, coversely, neglect liars who are lying using other neurocognitive mechanisms than just the ACC? These questions pose a serious challenge to the race for a neuroscience-based lie detector.
Another, more profound, ethical questions that this reserach raises is the following: do we really want to live in world without lying? Generally, lying is frowned upon. Yet, imagine if you had to tell the truth all the time. It is not only lawyers, such as the character Jim Carey plays in Liar Liar, that benefit from our ability to conceil our innermost thoughts and deceive. Lying plays an enormous role in human social life, some for bad, but some also for good. If lie detection devices should become succesful we will have to discuss when and where to use them. In the class room, at a job interview, in the minister’s office when we get married?
Langleben, D. et al. (2002): Brain activity during simulated deception: An event-related functional magnetic resonance study (PDF file). Neuroimage 15: 727-732.
Silberman, S. (2006): Don’t even think about lying. Wired 14.01.
Henig, R.M. (2006): Looking for the lie. New York Times Magazine. February 5, 2006.