Professors Patterson and Pardo have written a terrific and engaging book addressing the philosophical issues posed by neuroscience in the context of the legal system while not losing sight of the real-world implications of neuroscience in law.
This blog post focuses on the book authors’ discussion of neuroscience lie detection, a subject with many studies and no lack of commentary. Two conceptual issues are considered here: first, the relationship among minds, brains, and persons; and second, whether we must (or can) fully separate the conceptual issues of deception from the empirical issues of neuroscience lie detection.
The authors distinguish themselves first from the pure neuro-reductionists who posit that “the mind is the brain” yet reject as implausible the notion of Cartesian dualism. “Human beings have minds,” they state, “but minds are not the substances located within their bodies.” Rather, Pardo and Patterson look to the person as a whole: “To have a mind is to possess an array of rational and emotional powers, capacities, and abilities exhibited through thought, feeling, and action.”
Does the brain or the mind lie? Pardo and Patterson look to the person. “People, not their brains, lie. . . .” But clearly, the person’s cognition is dependent—at least in part—upon the brain. When a person decides to deceive, is it the person, the mind, or the brain that made the decision? How can we know? The brain and person are inseparable. And the mind, if it exists, is a dependent clause of the brain. Although the authors are convinced that distinguishing brain from mind is critical, I wonder whether it really is—at least for lie detection.
In the area of neuroscience lie detection, the authors’ conceptual concern is to determine the “scope and contours of what it means to lie.” This conceptual concern, they note, is at least as old as Aristotle. Revisiting these centuries-old concepts in light of the newfound ability to measure brain waves (EEG) and track hemoglobin moving through the brain (fMRI) is a fascinating venture. Do these technologies bring something new to the conceptual understanding of mind/brain? And in particular, to neuroscience lie detection?
I appreciate the authors’ elegant approach to these theoretical problems and agree with their claim that it is a “conceptual mistake to assume that brain-based lie detection provides direct access to lies [and] deception.” If successful, neuroscience lie detection will only establish that there are neural correlates of deception—nothing more. But perhaps that will be sufficient.
Neuroscience research certainly brings new ways of recording, measuring, and visualizing activity within the brain. However, other than claiming there is promising research to date, little can be said about neuroscience research on deception. If the data become more robust and supported by replicated studies—and that is a big if—neuroscience may provide more accuracy in understanding brain activity and how that relates to deception. The authors seem to agree that neuroscience may be useful in the future in lie detection, provided there is sufficient proof of neurological events meaningfully correlated with lying; a position with which I agree.
I am less convinced than the authors that we can tease apart the conceptual problem (the scope and contour of what it means to lie) from the empirical concerns (determining when a subject is lying). Research designs for neuroscience lie detection are entwined with many assumptions about brains, minds, truth, deception, intent, signaling, memory, and mistake. As an empirical matter, the troubling plasticity of memory and the ever-present problem of mistake may prove to be confounding problems that cannot be managed. And these empirical concerns are part and parcel of the scope and contours of deception.
More fundamentally, I am uncertain that we need to sort out all the conceptual issues related to neuroscience and law. We many never sort out the conceptual concerns and scholars may continue to disagree in perpetuity about the relationship of mind and brain and personhood. But for neuroscience lie detection, it may be enough if there are neural signals that are meaningfully correlated with intentional deception with known rates of error sufficiently low to constitute evidentiary reliability. This quest alone provides an entire universe of complexity that scientists have not resolved and indeed, may not.
But to my mind, the most interesting philosophical, legal, empirical, and societal questions arise if neuroscience lie detection really does succeed. . . . What do you think?