Table of Contents Introduction 2 I. The Rationalism Behind the Insanity Doctrine 8 A. Cognition and the Cognitive Prong of Insanity Tests 13 B. Cognition and the Volitional Prong of Insanity Tests 18 II. The Negligible Role of Emotions 22 A. "Moral Insanity" and the Lack of an Emotional Capacity Test 24 B. Lack of Self-Control and Emotional Disturbance 28 III. Emotions, Morality, and Antisocial Behavior: Insights From Neuroscience 30 A. "Knowing" Without "Feeling" Has a Negative Impact on Moral Judgment and Decision-Making 31 B. Self-Control Abilities Also Depend on Emotions 43 IV. A Tripartite Test for Legal Insanity 49 A. Limiting the Scope of the Cognitive Prong 50 B. Including an Emotional Prong 51 C. Integrating Emotions in the Substance of the Volitional Prong 55 D. Rethinking Diminished Capacity as Generic Partial Insanity 57 V. Normative Arguments Supporting an Emotion-Oriented Model of Legal Insanity 60 A. Personal Guilt 62 B. Culpability-Based Retribution 63 C. Rehabilitation 65 Conclusion 69 INTRODUCTION
The relationship between neuroscientific disciplines and legal insanity has never been simple. Many books and articles have been written, many conferences have been held, and many contrasting views have been proposed, but the debate continues. On the one side of the spectrum, some authors have called for neurological defense on the grounds that brain diseases may excuse the crime. (1) At the other end of the spectrum, some scholars have expressed concern that brain images and scans can actually mislead juries, giving them the wrong impression that the brain is wholly responsible for human behavior, which may allow for criminal conduct to be excused based on any brain abnormality in the defendant. (2) The lack of resolution of these disputes makes ambiguous the contribution of neuroscience to legal insanity, even at the theoretical level. This Article attempts to fill this gap and proposes one possible approach by which neuroscientific knowledge may plausibly contribute to a rethinking of the insanity doctrine without causing any dramatic upheaval to the nature of culpability and criminal responsibility.
Brain mechanisms do not alone account for an individual's (lack of) culpability. Culpability and insanity are not neuroscientific concepts, nor can they be localized in certain neural patterns. (3) Yet, although brain mechanisms cannot provide an answer to normative questions about culpability and criminal responsibility, (4) these physical features may become integral to discussions of culpability (and the lack thereof), as long as they contribute to a better understanding of the processes that underlie the capacities necessary for one to be considered culpable. This consideration of brain mechanisms, once again, does not equate to attributing a normative significance to neuroscience, nor to claiming that neuroscience could erode the nature of culpability and criminal responsibility. Rather, neuroscientific information can be used as a source of knowledge to improve the accuracy of the legal-psychological assumptions that support notions of culpability. Over the past thirty years, neuroscience research has greatly advanced our understanding of the dynamics that underlie decision-making processes leading to moral conduct. One of most relevant insights emerging from this research concerns the critical role that emotions and emotional processes play either in informing or in hindering moral decision-making. (5) In confirmation of this insight, brain-imaging studies on specific psychiatric populations characterized by marked antisocial tendencies have found links between these conditions and abnormal structure or functioning of the same socio-emotional brain circuits that appear to be significantly involved in moral decision-making. (6) Altogether, consistent with behavioral studies, research in neuroscience supports the view that emotions are crucial mediators for moral behavior; that is, moral behavior also depends largely on proper and balanced emotional functioning. (7)
This Article specifically uses this branch of neuroscientific knowledge to revise the cognitivist model of the capacity for moral rationality, which lies at the core of the insanity defense. It provides an alternative model of legal insanity: one that gives more prominence to individuals' emotional faculties in relation to the crime committed. Additionally, it offers several arguments for why an emotion-oriented model of legal insanity--informed by scientific knowledge--is normatively plausible.
The argument offered here proceeds as follows. Part I traces the cognitivist model of insanity in contemporary criminal law. It begins with a preliminary discussion of the intellectualistic view of the capacity for moral rationality, which forms the benchmark of culpability and criminal responsibility. As will be made plain, the capacity for moral rationality consists of one's ability to engage in instrumental practical reasoning dictated by moral reasons. Importantly, in the eyes of the law, the capacity for moral rationality is entirely governed by cognitive faculties. Therefore, agents may be considered culpable as long as they possess intact cognitive faculties that enable them to know or understand the meaning of their unlawful conduct and willfully choose to engage in that unlawful conduct accordingly. In sum, cognition is the only mental dimension that defines the legally relevant mind. Part I subsequently explores how the intellect-based understanding of the capacity for moral rationality is reflected in the insanity doctrine. By analyzing formulations of insanity standards, it highlights that insanity tests are fundamentally focused on the evaluation of a defendant's cognitive faculties at the time of the offence. On the one hand, cognitive defects are considered responsible for a defendant's lack of knowledge, or understanding, of the factual and moral meaning of the offense (cognitive prong of legal insanity). On the other hand, by impairing defendants' capacity for comprehension, cognitive defects are also assumed to affect their capacity to control their impulses (volitional prong of legal insanity).
Part II provides further support for the criminal law's adherence to an intellectualistic model of legal insanity by analyzing the negligible role that emotions are afforded within the evaluation of insanity. In line with this rationalist perspective, criminal law manifests a view that emotions make no positive contribution to moral rational reasoning. It presupposes that emotions are mental occurrences that, when excessively intense, can provoke sudden loss of control.
The negative relationship between emotions and the capacity for moral rationality is echoed in insanity standards in two ways. First, insanity standards do not provide an emotional capacity test, which is to say, a test measuring a defendant's capacity to emotionally appreciate the moral significance of the offence. Second, insanity standards give prominence to self-control impairments as long as they are linked to a defect of cognitive faculties. On the contrary, self-control impairments arising from emotional disturbance are usually considered as mitigating circumstances, to be considered in the sentencing phase or as limited diminished-capacity conditions, such as the common law "heat of passion" and the Model Penal Code's (MPC's) "extreme emotional disturbance" (EED). The diminished weight of emotion in such an evaluation, as I contend, is for one fundamental reason: because emotions are not treated as mental factors that contribute to one's capacity for moral rationality, a lack of self-control due to emotional impairment is not viewed as the kind of moral rationality defect that can justify an excuse.
Part III measures the rationalist model of legal insanity against neuroscientific insights into the role of emotions in moral judgments and decision-making. Its objective is not to carry out a detailed literature review of neuroscientific studies. Rather, and more narrowly, it aims to use relevant neuroscientific literature to emphasize two main mistaken assumptions about moral decision-making and behavior emerging from the current intellect-based model of legal insanity. First, it outlines that in moral judgments and decision-making processes, emotional faculties play a role equally critical to that of cognitive faculties. Notably, it emphasizes that emotions and emotional faculties influence moral judgments and decision-making at both subconscious and conscious levels (8) and, thus, that cognitive faculties alone cannot give rise to moral decisions without emotional influence. Second, the Article suggests that self-control abilities depend on their own mechanisms, encompassing many distinct (and dissociable) cognitive and socio-emotional processes. As such, people's capacity for self-control does not necessarily depend on the cognitive ability to know that a certain action is wrong.
In light of the highlighted scientific insights, Part IV draws up and proposes a tripartite model for legal insanity which accounts for the relevance of emotional factors. While the cognitive prong of the insanity tests remains essentially unaltered, the Article first advocates for the inclusion of an emotional capacity test--a test measuring defendants' capacity to emotionally appreciate the moral significance of their conduct--in insanity standards. Second, it advocates for the recognition of an independent volitional prong for the test, to measure the defendants' abilities to make decisions and exercise self-control, regardless of their intellectual ability to tell right from wrong. Furthermore, Part IV analyzes the consequences that the expansion of the substance of the volitional prong to also incorporate emotional components has for the diminished-capacity doctrine, as it is regulated by both the common law "heat of passion" and the MPC's EED standards.