NCPA - National Center for Policy Analysis


March 26, 2009

In the United States, the decision to impose criminal responsibility rests on an assumption about the defendant's decision to commit a crime.  We punish only those who we believe had the capacity to make a choice.  But could neuroscience excuse violent criminals?  New research may compel courts to distinguish between an "impulse that was irresistible" and an "impulse not resisted."

Currently, most states don't consider "impulsive aggression" a viable defense, holding that a sudden urge to act violently doesn't interfere with the ability to understand right and wrong.   But a new generation of neuro-imaging technologies could provide insights into structural and functional abnormalities in the brain that may limit the autonomy of many dangerous offenders and unravel the fabric of the criminal justice system, say researchers Daniel Shuman and Liza Gold.

Consider the ideas of autonomy and dangerousness:

  • Autonomy refers to the capacity of individuals to choose how to act and, consequentially, whom the criminal law should hold accountable; dangerousness is characterized by those who are prone to acting violently before thinking.
  • But the case for punishment rests on the assumption that offenders have the capacity to make choices, commonly referred to as free will.
  • Findings implicate a smaller role played by choice and a larger role played by structural and functional abnormalities in the brain bringing into question many of the basic assumptions of the criminal justice system.

But how will the results of these technologies be received by the courts -- are they relevant to existing formulations of the prima facie case, the insanity defense or mitigation of sentence?  They may play a role in assessing culpable mental states only if they are reliable. 

However, the results could undermine standards of criminal autonomy, forcing judges to evaluate science they don't understand, and "unravel the fabric of the criminal justice system," say Shuman and Gold.

Source: Daniel W. Shuman and Liza H. Gold, "Without Thinking: Impulsive Aggression and Criminal Responsibility," Behavioral Sciences and the Law, Vol. 26, November/December 2008.

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