Neuroscience and Law

Jeffery Rosen has a fascinating article in this week’s New York Times Magazine. While the article is balanced and careful, the “buy me, read me” headlines and several of the researchers that Rosen quotes suggest that a law-and-neuroscience revolution is brewing. I want to add my voice to the skeptics that Rosen quotes, though with a different perspective. To my mind, recent findings in the field of neuroscience will change law only at the margins; and its main contribution will be to confirm the central tenets of legal realism, and will thus have only minor effects on most legal concerns.


Take for example this (for lack of a better word) “discovery” about human cognition by Harvard’s Joshua Greene (who is a major figure in the article): “[M]oral judgments are not a single thing; it’s intuitive emotional responses and then cognitive responses that are duking it out.” I couldn’t agree more, but my first encounter with this perspective wasn’t in reports from a laboratory; I found it in the classic accounts of legal realism (which also happen to overlap with classical accounts in legal anthropology). It turns out that legal realists were, well, quite realistic about the way fact-finders and legal interpreters process information in legal cases. In fact, Dan Kahan and I recently wrote a piece describing how nicely the new research on human cognition was lining up with the central tenets of legal realism.

What does this science-based legal realism mean for the law? Not much, I think. This is, in part, because over the last half century legal realists have reconstructed a substantial part of the law to reflect their assumptions. Within the Uniform Commercial Code (not to mention many of the major reforms in the criminal law and torts) beats a legal realist heart. For the curious, I recommend a recent and straightforward post on the subject by Brian Tamanaha over at Balkinization.

But the new neuroscience isn’t just about the cognition of legal actors, it’s also (at least ostensibly) about the responsibility of law-violators. Here the finding of note is that some people may be neurologically prone to some types of illicit behavior — a finding that, it is suggested, will alter our basic conceptions of moral agency, making neuroscience defenses commonplace and potentially freeing many bad actors from responsibility for their actions. As Greene puts it: “The official line in the law is all that matters is whether you’re rational, but you can have someone who is totally rational but whose strings are being pulled by something beyond his control.”

Whatever the official line might be, the legal system has long dealt with precisely these kinds of claims. Take, for example, the failure of most of most “uncontrollable urge” defenses in the criminal law: Addicted? Have a violent temperament? Intoxicated? Psychotic? Only in the rarest of instances will the law let you off the hook. Even where someone is clearly deranged, incompetent, and suffering from various volitional constraints, many feel justified in handing down a death sentence. And attempts to restructure the law in light of volitional constraints have, by and large, failed (have a look, e.g., at the history and politics of California’s death penalty jurisprudence).

All of this makes sense if you view the law in expressive or evaluative terms: Judges and juries aren’t just trying to figure out whether the individual defendant did something that is deontologically wrong, they are also trying to figure out whether what the individual did expresses a disregard for morals the rest of us prize. The private moral life of the offender is only marginally relevant here; the real action is in evaluating the social meaning of the act and the social meaning of the legal system’s response. Moreover, even if the factfinder or sentencer thinks only terms of both deterrence and desert, the effects of the new neuroscience seem likely to be a wash. Any diminishing of moral responsibility will at least be partially offset by concerns about future bad acts, the message sent by a lenient sentence to other offenders, and so forth. And, as Rosen points out at the end of the article, the debates over what the law should do remain intact.

There are a number of tantalizing teasers about what neuroscience might one day reveal (thought-reading machines, precise lie detectors, and so on); but while fun to think about such speculations are, well, speculative.

So what to make of the legal implications of the new neuroscience? The new neuroscience deserves the attention of legal experts and the public. But I think it is miscast as producing “revolutionary,” Minority Report style changes; rather it’s furnishing additional evidence for claims that, by and large, we already accept as given. As for the future, perhaps we will have reason to worry, celebrate, or change our mind some day, but that day (sadly or thankfully) exists now only in science fiction.

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