Staff Working Paper

In approaching human behavior, science and ethics/law have different objectives and interests: science seeks to understand it, ethics seeks to judge it wisely. Law, the embodiment and teacher of many of the community’s shared moral practices and norms, seeks to protect the community against dangerous or unacceptable behavior by judging misconduct and punishing offenders. Although understanding and judging are different activities, efforts to understand criminal behavior and its causes continue to exert an influence on how society deals with criminals, not only in considering guilt and innocence, but, for example, in sentencing, decisions about parole, and proposals for mandatory treatment, as well as in communal efforts to prevent people from becoming criminals in the first place. In previous generations, people looked to inheritance (genetics), anatomical features (phrenology), a history of emotional trauma or unresolved psychic conflicts (psychoanalysis), or socioeconomic deprivation (sociology and economics) to explain why some people commit crimes and others do not. Today and tomorrow, it seems, people will look increasingly to the brain (neuroscience). It is none too soon to begin to think about how neuroscience will and should affect our legal judgments and practices.

Although the law generally still holds people personally responsible for their actions, various accommodations have been made in the past to the findings of those who offer explanations for misconduct. In addition to making room for justifications (e.g., self-defense), the criminal law already accepts legitimate excuses that can lead to verdicts of “not guilty” (e.g., by reason of insanity); it considers mitigating factors (e.g., extreme provocation, mental incapacity) in determining sentencing; it uses medical treatments that are made conditions of parole (e.g., chemical castration for pedophiles). And it is easy to imagine how similar kinds of accommodations and adjustments might be granted for brain-based explanations, should these be forthcoming from neuroscience. Indeed, neuro-scientific findings have already begun to find their way into criminal trials and other aspects of the criminal law, notwithstanding the immaturity of the science, and there is every reason to expect much more of this in the future. To help the Council think about the significance of neuroscience for the criminal law, staff has prepared this review of the uses of neuroscientific evidence in criminal trials.

Over the last several meetings, the Council has begun to explore the subject of neuroscience, brain, and behavior as a possible topic of inquiry, and has focused some specific attention on the relationship between neuroimaging and moral responsibility.  One possible entry point into this domain is through reflection on the impact that neuroscience in general (and neuroimaging in particular) have had on the administration of criminal justice.  This is a fruitful approach in that the criminal law already has within it mechanisms and processes aimed at the determination of moral responsibility, and it admits expert medical witnesses to testify to a defendant’s state of mind.  This background paper essays to outline briefly the nature and scope of these mechanisms and the way in which neuroimaging and neuroscience testimony have to date augmented and affected their function.  To this end, it will be necessary first to give a summary account of the role that determination of moral responsibility plays in criminal law, both in the context of determination of guilt and the imposition of punishment.  Next, it will be necessary to address briefly the procedural threshold questions of the admissibility of neuroimaging evidence, as well as the constitutional entitlement to present such evidence.  There will then follow an extended discussion, with reference to specific cases, of the present and projected application of neuroimaging evidence to the legal mechanisms for the determination of criminal responsibility.

Criminal law is itself inextricably intertwined with the concept of moral responsibility.  Indeed, a central distinction between criminal and civil law is that the sanctions of the former carry with them the moral censure of the polity, whereas the latter do not.  “Crime” has itself been defined by one commentator as “conduct which, if duly shown to have taken place, will incur a formal and solemn pronouncement of the moral condemnation of the community.”¹ A central function of criminal law is thus the punishment of wrongdoers who transgress society’s memorialized values.  Prior to the imposition of punishment, however, the criminal defendant must be adjudged culpable of the charged offense, and thus worthy of society’s blame.  Thus, as one member of this Council has rightly observed, “culpability is the hallmark of modern criminal law.”² 

The two chief activities of the criminal law -- determination of guilt and imposition of punishment -- turn largely on questions of culpability and blameworthiness.  Within the context of determining guilt, the doctrine of mens rea is primarily driven by questions of personal responsibility and intention; a failure to prove beyond a reasonable doubt that the defendant had the requisite culpable mental state can result in either acquittal or conviction on a lesser charge.  Similarly, the affirmative defense of excuse directly implicates the question of moral culpability.  Nowhere is this more dramatically demonstrated than in the context of the excuse defense of insanity, where the relevant inquiry often focuses on whether the defendant could distinguish right from wrong, or conform his behavior to an appropriate standard.  The processes in place for determining criminal punishment (that is, sentencing) are likewise aimed largely at the question of moral responsibility: “The criminal law will generally only impose its retributive or deterrent sanctions upon those who are morally blameworthy – those who know they are doing wrong but nonetheless persist in wrongdoing.”³  There are procedures in place allowing litigants to introduce evidence of mitigation or aggravation, in their effort to influence the sentencing court’s decision. Expert psychiatric testimony is frequently introduced intro criminal proceedings, both for determining guilt and for assigning punishment.

1. The Doctrine of Mens Rea.

Coke’s maxim, “Actus Non Facit Reus Nisi Mens Sit Rea”^{4 i} is a seminal principle in American criminal law.    With very few exceptions, criminal guilt cannot be established merely by demonstrating that a particular act was committed; it must also be shown that the defendant acted with the requisite intention for each element of the offense in question.  The Model Penal Code (which has been adopted in one form or another by a majority of jurisdictions) sets forth four types of culpable mental states for purposes of mens rea analysis (listed from most culpable to least culpable): Purposefulness  (acting with the conscious purpose to engage in specific conduct or to cause a specific result);⁵ Knowledge (awareness that one’s conduct is of a particular nature, or the practical certainty that one’s conduct will cause a specific result”);⁶ Recklessness (conscious disregard for a substantial and unjustifiable risk”);^{7 ii} and Negligence (the creation of a substantial or known risk of which one ought to have been aware).^{8 iii} The failure to prove the requisite degree of culpability for any element of the charged crime will result in either a finding of not guilty or conviction on a less serious offense. 

For example, the Model Penal Code establishes three types (degrees) of criminal homicide – murder, manslaughter, and negligent homicide.⁹   The various types of criminal homicide share the same actus reus, namely, “caus[ing] the death of another human being,” but are distinguishable based on whether the defendant did so purposely or knowingly (murder), recklessly (manslaughter), or negligently (negligent homicide).  Thus, the moral gravity of the offense (and the severity of punishment) is deemed greater to the extent that it can be shown that the defendant’s decision was based on cool calculation rather than a momentary rash impulse.  Thus, if a person charged with murder can show that he was “acting under the influence of extreme mental or emotional disturbance for which there is a reasonable explanation or excuse,”^{10 iv} he will be found not guilty, or will be charged instead with manslaughter – a significantly less serious offense which carries a lesser punishment.

In this way, the doctrine of mens rea not only distinguishes among various degrees of moral culpability, but also makes room for the notion that under certain circumstances of provocation or mental abnormality, moral responsibility for one’s actions is diminished, rendering one deserving of a more lenient punishment.

2. The Defense of Excuse

The doctrine of excuse provides another clear illustration of the relationship between criminal law and moral responsibility.  The law “excuses” criminal conduct if there are circumstances that negate the moral blameworthiness of the actor.  In Holloway v. U.S. (1945), the United States Court of Appeals for the D.C. Circuit formulated the doctrine thusly:  “Our collective conscience does not allow punishment where it cannot impose blame.”¹¹  Renowned criminal law professor Sanford Kadish elaborated:

To blame a person is to express moral criticism, and if the person’s action does not deserve criticism, blaming him is a kind of falsehood, and is, to the extent the person is injured by being blamed, unjust to him.  This lies behind the law’s excuses.¹²

There are a variety of excuses that can serve as affirmative defenses.  Two are particularly relevant to the present inquiry:  insanity and infancy.

(a) The Excuse of Insanity

The species of excuse defense that perhaps most clearly illustrates the nexus between criminal law and moral responsibility is the insanity defense.  The insanity defense rests on the premise that it is unjust to hold an irrational individual morally (and by extension, criminally) responsible.  Again, the DC Circuit gave voice to this intuition in the Holloway case:  “To punish a man who lacks the power to reason is as undignified and unworthy as punishing an inanimate object or animal.  A man who cannot reason cannot be subject to blame.”¹³   There are a variety of competing approaches to the insanity defense.  One test for insanity, the “M’Naghten Rule,” requires proof that “at the time of the committing of the act, the party accused was laboring under such a defect of reason, from disease of mind, as not to know the nature and quality of the act he was doing; or if he did know it, he did not know he was doing what was wrong.”¹⁴ An alternative approach is the “irresistible impulse” test, which asks whether mental disease impaired the defendant’s ability to control his actions.  The “Durham Rule” holds that “an accused is not criminally responsible if his unlawful act was the product of mental disease or defect.”¹⁵   The American Law Institute developed a test for insanity as part of its Model Penal Code which holds that “a person is not responsible for criminal conduct if at the time of such conduct as a result of mental disease or defect he lacks substantial capacity to either appreciate the criminality of his conduct or to conform his conduct to the requirements of the law.”  Among these approaches, the M’Naghten and ALI rules are the overwhelming preferences for state legislatures.  Almost all states have adopted one or the other on a nearly equal basis.  Very few jurisdictions have adopted either the Durham rule or the irresistible impulse test.  The federal test for insanity, established by the “Insanity Defense Reform Act of 1984” (enacted in response to John Hinckley, Jr.’s acquittal by reason of insanity), requires the defendant to demonstrate by clear and convincing evidence that “at the time of commission of the acts constituting the offense, the defendant, as a result of severe mental disease or defect, was unable to appreciate the nature and quality or the wrongfulness of his acts.”¹⁶ The statute further specifies that “mental disease or defect does not otherwise constitute a defense.”¹⁷

Despite the differences in the competing approaches to the excuse defense of insanity, they all originate from the intuition that an individual’s moral blameworthiness (and thus criminal responsibility) is mitigated when his reason is impaired by mental defect or abnormality.

(b) The Excuse of Infancy

Another doctrine of excuse relevant to the present inquiry is the defense of infancy.  This affirmative defense excuses criminal conduct of children below a certain age on the grounds that they are incapable of forming the requisite intent and are not susceptible to deterrence.  The relevant age is prescribed by statute.

B. Imposition of Punishment

The process of imposing punishment is also animated by principles of moral responsibility.  Criminal punishment, as stated above, aims at meting out justice, deterring future misconduct, and expressing society’s condemnation for the transgression of its norms.  The process of criminal sentencing finds both defendants and prosecutors making moral appeals to the sentencing authority, seeking lenience or arguing for severity.  Defendants will regularly argue that they should be shown mercy on the grounds that they, while guilty as a matter of law, are the victims of harsh circumstances or misfortune – abuse, poverty, and the like.  Defendants also often argue for leniency on the grounds that they do not pose a grave ongoing threat to society.  Conversely, prosecutors commonly argue that severe punishments are in order based on the heinous nature of the original offense, or the defendant’s propensity for future dangerousness.  In cases involving the death penalty, this process is somewhat more formalized with a (statutorily defined) weighing of aggravating and mitigating factors.  In such circumstances, as a matter of constitutional right (under the Eighth and Fourteenth Amendments), “the sentencer . . . [shall] not be precluded from considering, as a mitigating factor, any aspect of a defendant’s character or record and any of the circumstances of the offense that the defendant proffers as a basis for a sentence less than death.”¹⁸

II. Preliminary Procedural Issues

Before moving to the discussion of how neuroimaging evidence has been or may in the future be used within the aforementioned framework for the determination of guilt and imposition of punishment, it is useful to address very briefly the procedural threshold questions of admissibility of and constitutional entitlement to such evidence.

A. Scientific Evidence

There are essentially two standards for the admission of scientific evidence, both named for the cases in which they were ennunciated: Daubert and Frye.  Courts following the Frye approach admit only scientific testimony regarding theories and methodologies that have gained “general acceptance” among members of the relevant scientific field.¹⁹ The Daubert rule rejects this singular reliance on “general acceptance” and instead vests the trial judge with the responsibility to assess whether the proffered expert testimony is both reliable and scientifically valid.²⁰  In evaluating “validity,” courts are directed to consider a range of factors including general acceptance, peer review, error rates, and amenability to falsification.²¹  The Daubert standard applies in federal court, and a large array of state courts.  The Frye standard controls in approximately 20 state jurisdictions.

If a court regards proffered neuroimaging evidence as too novel, it will sometimes deny its admission into evidence under the Frye standard, on the grounds that it has yet to achieve “general acceptability.”  Such was the case in People v. Protsman,²² in which the defendant sought to admit PET scan evidence and psychiatric testimony to the effect that he was suffering from decreased frontal lobe activity (due to traumatic brain injury) such that he could not formulate the requisite intent for first degree murder.  Because the evidence had not yet achieved general acceptance, it was not admissible.  Similarly, in People v. Chul Yum,²³ the defendant (who had been convicted of second degree murder) argued on appeal that the trial court erroneously refused to admit his proffered evidence of a SPECT brain scan which he claimed showed diminished activity in his left temporal lobe and damage caused by brain trauma, causing him to kill his mother and sister.  Because of the novelty of the diagnostic approach (i.e., using a SPECT scan to diagnose brain trauma and post traumatic stress disorder), the defendant failed to satisfy the court that the scientific evidence was “generally accepted.”

There are, however, many noteworthy examples of cases in which neuroimaging evidence has met the requisite standards for scientific testimony and has been admitted (both from jurisdictions that follow Daubert rather than Frye, and in Frye jurisdictions where the judge was convinced that the proffered evidence met the “general acceptance” standard).  These cases are set forth throughout the discussion below.

The United States Supreme Court has ruled that “the Constitution requires that a State provide access to a psychiatrist’s assistance” when the question of a criminal defendant’s sanity is being litigated.²⁴   At least one court has held that this right extends to the provision of neuroimaging tests; in People v. Jones, the appeals court reversed the defendant’s murder conviction on the grounds that he was denied neurological testing that supported his defense that he was suffering from brain damage that impaired his “ability to think quickly and flexibly” and “ability to perceive risk.”²⁵ Additionally, it was reported that in 1998 a trial judge allocated money for a CT scan and MRI for the defendant Jeremy Strohmeyer, on trial for the murder of a seven year old child in Las Vegas, Nevada.²⁶

A. Determination of Guilt

There are a few noteworthy instances in which neuroimaging evidence has been introduced at the guilt phase of the criminal process to support claims of lack of requisite culpable mental state or excuse defenses based on insanity.  These are detailed below, by category.

1. Negation of Mens Rea. 

There are several cases in which defendants sought to admit neuroimaging evidence that they were incapable of formulating the requisite culpable mental state and were thus entitled to acquittal or conviction on a less serious charge.  Some defendants have succeeded in getting this evidence before the jury (a noteworthy achievement in itself), but in the main, this approach has not been overwhelmingly successful.  That said, it is difficult to develop a metric for success in this context, as many of these cases ended in plea bargains rather than convictions or acquittals.  In any event, there does seem to be a significant (and growing) volume of cases in which neuroimaging evidence is adduced to negate mens rea.

In United States v. Erskine,²⁷ the defendant (who had been convicted of making false statements to an official of a federally insured bank) argued on appeal that the court erroneously prevented him from introducing testimony and a brain scan that he claimed showed that he lacked the mental capacity to formulate the specific intent to “influence a bank” (a statutory element of the crime with which he was charged).  The U.S. Court of Appeals for the Ninth Circuit agreed that he was entitled to introduce such evidence on the issue of specific intent (though it expressed no opinion as to the probative nature of such evidence).  Thus, the defendant’s conviction was reversed.^v Similarly, in 1995, former United Way executive William Aramony (charged with numerous counts of embezzlement from the charity fund), introduced neuroimaging evidence in support of his claim that he was suffering from “brain atrophy” and thus unable to satisfy the requisite intent requirement to commit embezzlement.  Shortly after this evidence was introduced, he secured a favorable plea bargain.

Other defendants have not been as successful in demonstrating a lack of mens rea by appeal to neuroimaging evidence.  In State v. Anderson,²⁸ the defendant presented to the jury expert testimony (supported by neuroscience evidence) that brain-damage-induced depression and paranoia precluded him from being able to premeditate and deliberate in a manner sufficient to justify the charge of first-degree murder.  The jury was not persuaded and found him guilty on all counts.  In U.S. v. Mezvinsky,²⁹ the court held that the defendant (who had been indicted on 66 counts of fraud and related offenses) was not entitled to introduce PET scan evidence in support of his claim that he was incapable of deception (the requisite mens rea for his charges).

2. Excuse Defense of Insanity

There are a few very high profile examples of the introduction of neuroimaging evidence as an adjunct to a claim of not guilty by reason of insanity.  For example, in U.S. v. Hinckley,³⁰ the defendant (who attempted to assassinate President Reagan) presented CT scan evidence showing “atrophy” of the brain. The neuroradiologist for the defense testified that the degree of atrophy was abnormal and possibly indicated the presence of organic brain disease.  Another witness for the defense (a psychiatrist) testified that the evidence of atrophy increased the statistical likelihood that the defendant was suffering from schizophrenia.  The court ultimately admitted this evidence in order to give the jury “all possibly relevant evidence bearing on cognition, volition, and capacity” in considering the defendant’s insanity defense.  The defendant was found not guilty by reason of insanity.

In another high profile case, People v. Weinstein,³¹ the defendant (accused of strangling and defenestrating his wife), successfully introduced PET scan images, which he asserted showed reduced brain function in and around an arachnoid cyst in his frontal lobe.  The evidence was presented in support of the defense’s theory that Weinstein was not responsible for his actions due to mental disease or defect.  The prosecution vigorously opposed the admission of this evidence, and moved to exclude it.  Shortly after the judge ruled it to be admissible, the prosecution quickly agreed to negotiate a plea bargain for a reduced charge of manslaughter.  It seems reasonable to infer that the prosecution was concerned that the images would be persuasive to jurors at trial.

One might speculate that as the ability to perform neurological testing for the biological correlates of schizophrenia and related disorders grows, so too will the incidence of defendants moving for the admission of such evidence in support of their claims of insanity. That said, the insanity defense is rarely invoked, and is even more rarely successful.

B. Imposition of Punishment

While there are few reported cases in which defendants have secured acquittals on the strength of neuroimaging evidence, defendants have enjoyed some measure of success in the context of sentencing.  For example, such evidence has been introduced as an adjunct to support a plea for leniency or claim of mitigating circumstances.

In early 2004, MRI and PET scan evidence helped to defeat two separate death sentences for Simon Pirela.  In April of 1983, Mr. Pirela received a death after being convicted of murder (Commonwealth v. Pirela); and in May of 1983 Pirela received another death sentence, in a separate murder trial (Commonwealth v. Morales^vi).   When the Morales sentence was vacated (due to reversible error for prosecutorial misconduct) and resentencing ordered, attorneys for Pirela introduced MRI and PET scans as evidence in support of mitigating factors of diminished capacity, brain damage and mental impairment generally.  The jury recommended unanimously that Pirela be resentended to life in prison rather than executed.³²   On appeal for Pirela’s second death sentence, attorneys for the defendant used the same PET and MRI scans to support the defense claim that Pirela was mentally retarded, thus requiring the court to vacate the death sentence and impose life imprisonment.^{33 vii}  The Judge in Pirela noted that the expert testimony on the brain scans, combined with neuropsychologists’ testimony, “was quite convincing.”

Similarly, in McNamara v. Borg,³⁴ PET scan evidence was introduced in support of the defendant’s mitigation claim that he was suffering from schizophrenia.  The defendant was sentenced to life imprisonment rather than execution.  According to post-sentencing interviews, jurors acknowledged that they were significantly influenced by the neuroimaging evidence in their decision to spare the defendant’s life.

There is at least one case in which the failure to allow neuroimaging evidence at the sentencing phase of trial was held to be reversible error.  In Hoskins v. State,³⁵ the Florida Supreme Court vacated the defendant’s death sentence and remanded the case for a new penalty proceeding so that the defendant would have an opportunity to present a PET scan showing a brain abnormality.

In contrast to the foregoing, there are numerous examples of cases in which the defense’s mitigation arguments supported by neuroimaging evidence were not persuasive to the jury.  For example, in People v. Kraft,³⁶ the defendant (convicted of 16 counts of murder and assorted other crimes) introduced PET scan images during his mitigation case, which experts testified were consistent with obsessive-compulsive disorder.  The jury was unmoved by this evidence and sentenced Kraft to death.  Similarly, in People v. Holt,³⁷ the defendant (convicted of murder, robbery, rape, and other crimes) introduced PET scan images and an EEG showing abnormalities in both temporal lobes and damage to the cingulate gyrus region of the brain, which experts testified was consistent with aberrant sexual behavior. The jury was not persuaded by this mitigation evidence and sentenced the defendant to death.   

Recent news reports suggest that a coalition of psychiatric organizations is currently drafting an amicus brief for an upcoming Supreme Court case involving the juvenile death penalty in which they will make an appeal to neuroimaging evidence.  These groups will argue (in the spirit of the infancy defense) that execution of juveniles violates the Eighth Amendment’s proscription on cruel and unusual punishment, because teenagers, by virtue of their immature brains, lack the requisite culpability to warrant the ultimate punishment.  The argument is based on MRI scans showing that frontal lobe development (which the advocates argue is the seat of moral judgment) is not yet complete during adolescent years. 

It bears noting that prosecutors might someday also seek to introduce neuroimaging evidence in the sentencing phase of the criminal process.  Such evidence might prove useful in demonstrating aggravating factors such as future dangerousness, drug or alcohol addiction, and the like, in an effort to secure a more severe punishment or even the denial or revocation of parole. To this point, there are no known cases in which neuroimaging data have been used in determining fitness for parole.

IV. Conclusion

The determination of moral responsibility is an integral function of the criminal law, both at the guilt and punishment phases. Science-based testimony (usually psychiatric) has already established a legitimate place in both phases. Neuroimaging technology, still in its infancy, has already had a modest impact on this process.  At the guilt phase, neuroimaging evidence has been marshaled in support of claims of insufficient mens rea and as an adjunct to the insanity defense.  At the punishment phase, neuroimaging evidence has been introduced to support claims of mitigation, with a noteworthy measure of success.

While the success rate of arguments supported by neuroimaging evidence in the criminal context is somewhat mixed, the large number of cases in which such evidence is presented is striking.  Many courts have admitted this evidence, and more will follow as the science underlying neuroimaging becomes more “generally accepted” (for purposes of the Frye test).  The incidence of neuroimaging evidence is also likely to increase as more courts follow the lead of People v. Jones and come to regard access to neuroimaging as part and parcel of the psychiatric testimony to which the defendant is constitutionally entitled.  Also, as neuroimaging evidence becomes more widespread and word of related successes becomes well known, criminal defense attorneys may come to regard it as standard practice.  Indeed, there are a handful of cases that have held that the failure of defense attorneys to investigate and present evidence of their client’s organic brain damage constituted ineffective assistance of counsel – a notoriously high threshold to satisfy.³⁸

Looking forward, it seems that criminal sentencing, where the defense counsel is afforded wide latitude to introduce any and all information that might persuade the jury to act leniently, presents the most fertile opportunity for argument supported by neuroimaging.  Particularly if the following anecdote, as reported by the Los Angeles Times, proves to be true: 

Jurors can be dazzled by the display.  Christopher Plourd, a San Diego criminal defense attorney, remembers well the first time he use PET scans in the early 1990s during a murder trial.  “Here was this nice color image we could enlarge, that the medical expert could point to,” Plourd said.  “It documented that this guy had a rotten spot in his brain.  The jury glommed onto that.”³⁹

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Footnotes

1. Literally, “the act is not criminal unless the mind is criminal.”
2. “The risk must be of such a nature and degree that, considering the nature and purpose of the actor’s conduct and the circumstances known to him, its disregard involves a gross deviation from the standard of conduct that a law-abiding person would observe in the actor’s situation.”  MPC 2.02(2)(c).
3. “The risk must be of such a nature and degree that the actor’s failure to perceive it, considering the nature and purpose of his conduct and the circumstances known to him, involves a gross deviation from the standard of care that a reasonable person would observe in the actor’s situation.”  MPC 2.02(2)(d).
4. “The reasonableness of the such explanation or excuse shall be determined from the viewpoint of a person in the actor’s situation under the circumstances as he believes them to be.”  MPC 210(1)(b).
5. There is no published record of the disposition of this case on remand.
6. “Morales” was an alias used by Simon Pirela. 
7. In Atkins v. Virginia, the U.S. Supreme Court held that execution of the mentally retarded violates the 8^th Amendment injunction against cruel and unusual punishment.  536 U.S. 304 (2002).

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Endnotes

1. Henry M. Hart, Jr., “The Aims of the Criminal Law,” 23 Law and Contemporary Problems 401 (1958).
2. Rebecca Dresser, “Culpability and Other Minds,” 2 Southern California Interdisciplinary Law Journal  41 (Spring 1993).
3. In re Devon T, 584 A.2d 1287 (Md. App. 1991).
4. Edward Coke, The Third Part of the Institutes of the Law of England 107 (1644).
5. Model Penal Code 2.02(2)(a).
6. Id. at (b).
7. Id. at (c).
8. Id. at (d).
9. Id. at 210.1 – 210.4.
10. Id. at 210.3(1)(b).
11. 148 F.2d 665, 65-67 (DC Cir 1945).
12. Sanford Kadish, “Excusing Crime,” 75 California Law Review 257, 263-65  (1987).
13. 148 F.2d 665, 65-67 (DC Cir 1945).
14. M’Naghten’s Case, 8 Eng. Rep. 718, 722 (1843).
15. Durham v. United States, 214 F.2d 862 (D.C. Cir. 1954).
16. 18 U.S.C 17 (1992).
17. Id.
18. Lockett v. Ohio, 438 U.S. 586, 604-05 (1978).
19. Frye v.United States, 293 F. 1013, 1014 (1923).
20. Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 592-94 (1993)
21. See id. at 593; see also Jennifer Kulynych, “Psychiatric Neuroimaging Evidence: A High-Tech Crystal Ball?” 49 Stanford Law Review 1249, 1263 (1997).
22. 88 Cal. App. 4^th 509 (2001).
23. 111 Cal. App. 4^th 635 (2003).
24. Ake v. Oklahoma, 470 U.S. 68, 74 (1985).
25. 620 NYS2d 656 (1994).
26. See Las Vegas Review-Journal 8/30/98; National Law Journal 9/21/98.
27. 588 F.2d 721 (9^th Cir. 1978).
28. 79 S.W.3d 420 (Mo. 2002)
29. 206 F. Supp 2d 661 (D. Pa. 2002).
30. 525 F. Supp. 1324 (D.D.C. 1981).
31. 591 N.Y.S.2d 715 (1992).
32. 549 Pa. 400, 701 A.2d 516 (1997).
33. Jan. Term, 1983, No. 2143 (Phila C.P. Apr. 30, 2004).
34. 923 F.2d 862 (9^th Cir. 1991).
35. 735 So.2d 1281 (Fla. 1999).
36. 23 Cal. 4^th 978 (2000).
37. 15 Cal. 4^th 619 (1997).
38. See, e.g., People v. Morgan, 187 Ill. 2d 500 (Ill. 1999).
39. Eric Bailey, “California and the West; Defense Probing Brain to Explain Yosemite Killings; Crime: Cary Stayner is among a Number of Defendants Whose Lawyers are Looking for Physical Explanations for Brutal Murders,” The Los Angeles Times, Part A; Part 1; Page 3 (June 15, 2000).