When laws or legal principles mention mental states such as intentions to form a contract, knowledge of risk, or purposely causing a death, what parts of the brain are they speaking about? We argue here that these principles are tacitly directed at our prefrontal executive processes. Our current best theories of consciousness portray it as a workspace in which executive processes operate, but what is important to the law is what is done with the workspace content rather than the content (...) itself. This makes executive processes more important to the law than consciousness, since they are responsible for channeling conscious decision-making into intentions and actions, or inhibiting action.We provide a summary of the current state of our knowledge about executive processes, which consists primarily of information about which portions of the prefrontal lobes perform which executive processes. Then we describe several examples in which legal principles can be understood as tacitly singling out executive processes, including principles regarding defendants’ intentions or plans to commit crimes and their awareness that certain facts are the case, as well as excusatory principles which result in lesser responsibility for those who are juveniles, mentally ill, sleepwalking, hypnotized, or who suffer from psychopathy. (shrink)

Neuroscience can relate to ethics and normative issues via the brain’s cognitive control network. This network accomplishes several executive processes, such as planning, task-switching, monitoring, and inhibiting. These processes allow us to increase the accuracy of our perceptions and our memory recall. They also allow us to plan much farther into the future, and with much more detail than any of our fellow mammals. These abilities also make us fitting subjects for responsibility claims. Their activity, or lack thereof, is at (...) the heart of culpability. For instance, planning to kill someone is strong evidence of what the law calls mens rea—a guilty mind. Claims about norms, or ethical “should” claims, express two-level propositions, directed at the behaving person at one level, and at that person’s mind and cognitive control network at another level. Thus, “People should stop themselves from hurting others,” is a claim about how people should behave and also a claim about how their cognitive control networks should behave—i.e., they should inhibit harmful behavior, or the intentions leading up to it. Planning is both an ability of the full person, and of that person’s mind. Neuroscience affirms the common notion, seen both in law and folk psychology, that what makes us guilty or culpable are certain events and states that exist in our minds. Overt behavior, including speech, is fallible evidence of these states and processes. Cases of negligence still involve the executive processes, but “negatively,” in that negligence results when certain types of executive activity fail to take place. (shrink)

[This download contains the Table of Contents and Chapter 1.] This first book-length study of confabulation breaks ground in both philosophy and cognitive science.

[This download includes the table of contents and chapter 1.] -/- When we praise, blame, punish, or reward people for their actions, we are holding them responsible for what they have done. Common sense tells us that what makes human beings responsible has to do with their minds and, in particular, the relationship between their minds and their actions. Yet the empirical connection is not necessarily obvious. The “guilty mind” is a core concept of criminal law, but if a defendant (...) on trial for murder were found to have serious brain damage, which brain parts or processes would have to be damaged for him to be considered not responsible, or less responsible, for the crime? The authors argue that evidence from neuroscience and the other cognitive sciences can illuminate the nature of responsibility and agency. They go on to offer a novel and comprehensive neuroscientific theory of human responsibility. (shrink)

[This download contains the introductory chapter.] People confabulate when they make an ill-grounded claim that they honestly believe is true, for example in claiming to recall an event from their childhood that never actually happened. This interdisciplinary book brings together some of the leading thinkers on confabulation in neuroscience, psychiatry, psychology, and philosophy.

[This download contains the Table of Contents and Chapter 1]. I argue here that the claim that conscious states are private, in the sense that only one person can ever experience them directly, is false. There actually is a way to connect the brains of two people that would allow one to have direct experience of the other's conscious, e.g., perceptual states. This would allow, for instance, one person to see that the other had deviant color perception (which was masked (...) by correct linguistic practice). This could be achieved by connecting one person's set of executive processes (or cognitive control network) to the conscious perceptual states of the other. Chapter 5 contains an internalist physicalist account of color according to which colors exist only as brain states. Their function is to enable more precise causal interactions between the executive processes and the brain's perceptual systems. This in turn allows for more precise action: I can select the red apples and leave the green ones. (shrink)

We present a theory of human artistic experience and the neural mechanisms that mediate it. Any theory of art has to ideally have three components. The logic of art: whether there are universal rules or principles; The evolutionary rationale: why did these rules evolve and why do they have the form that they do; What is the brain circuitry involved? Our paper begins with a quest for artistic universals and proposes a list of ‘Eight laws of artistic experience’ -- a (...) set of heuristics that artists either consciously or unconsciously deploy to optimally titillate the visual areas of the brain. One of these principles is a psychological phenomenon called the peak shift effect: If a rat is rewarded for discriminating a rectangle from a square, it will respond even more vigorously to a rectangle that is longer and skinnier that the prototype. We suggest that this principle explains not only caricatures, but many other aspects of art. Example: An evocative sketch of a female nude may be one which selectively accentuates those feminine form-attributes that allow one to discriminate it from a male figure; a Boucher, a Van Gogh, or a Monet may be a caricature in ‘colour space’ rather than form space. Even abstract art may employ ‘supernormal’ stimuli to excite form areas in the brain more strongly than natural stimuli. Second, we suggest that grouping is a very basic principle. The different extrastriate visual areas may have evolved specifically to extract correlations in different domains , and discovering and linking multiple features into unitary clusters -- objects -- is facilitated and reinforced by direct connections from these areas to limbic structures. In general, when object-like entities are partially discerned at any stage in the visual hierarchy, messages are sent back to earlier stages to alert them to certain locations or features in order to look for additional evidence for the object . Finally, given constraints on allocation of attentional resources, art is most appealing if it produces heightened activity in a single dimension rather than redundant activation of multiple modules. This idea may help explain the effectiveness of outline drawings and sketches, the savant syndrome in autists, and the sudden emergence of artistic talent in fronto-temporal dementia. In addition to these three basic principles we propose five others, constituting a total of ‘eight laws of aesthetic experience’. (shrink)

The patient with Capgras’ syndrome claims that people very familiar to him have been replaced by impostors. I argue that this disorder is due to the destruction of a representation that the patient has of the mind of the familiar person. This creates the appearance of a familiar body and face, but without the familiar personality, beliefs, and thoughts. The posterior site of damage in Capgras’ is often reported to be the temporoparietal junction, an area that has a role in (...) the mindreading system, a connected system of cortical areas that allow us to attribute mental states to others. Just as the Capgras’ patient claims that that man is not his father, the patient with asomatognosia claims that his arm is not really his. A similar account applies here, in that a nearby brain area, the supramarginal gyrus, is damaged. This area works in concert with the temporoparietal junction and other areas to produce a large representation of a mind inside a body situated in an environment. Damage to the mind-representing part of this system (coupled with damage to executive processes in the prefrontal lobes) causes Capgras’ syndrome, whereas damage to the body-representing part of this system (also coupled with executive damage) causes asomatognosia. (shrink)

Neuroscience can relate to ethics and normative issues via the brain’s cognitive control network. This network accomplishes several executive processes, such as planning, task-switching, monitoring, and inhibiting. These processes allow us to increase the accuracy of our perceptions and our memory recall. They also allow us to plan much farther into the future, and with much more detail than any of our fellow mammals. These abilities also make us fitting subjects for responsibility claims. Their activity, or lack thereof, is at (...) the heart of culpability. For instance, planning to kill someone is strong evidence of what the law calls men rea—a guilty mind. Claims about norms, or ethical “should” claims, express two-level propositions, directed at the behaving person at one level, and at that person’s mind and cognitive control network at another level. Thus, “People should stop themselves from hurting others,” is a claim about how people should behave and also a claim about how their cognitive control networks should behave—i.e., they should inhibit harmful behavior, or the intentions leading up to it. Planning is both an ability of the full person, and of that person’s mind. Neuroscience affirms the common notion, seen both in law and folk psychology, that what makes us guilty or culpable are certain events and states that exist in our minds. Overt behavior, including speech, is fallible evidence of these states and processes. Cases of negligence still involve the executive processes, but “negatively,” in that negligence results when certain types of executive activity fail to take place. (shrink)

When people confabulate, they make an ill-grounded claim that they honestly believe is true, for example recalling an event from their childhood that never actually happened. This interdisciplinary book brings together some of the leading thinkers on confabulation in neuroscience, psychiatry, psychology, and philosophy.

Almost everyone who has a limb amputated will experience a phantom limb--the vivid impression that the limb is not only still present, but in some cases, painful. There is now a wealth of empirical evidence demonstrating changes in cortical topography in primates following deafferentation or amputation, and this review will attempt to relate these in a systematic way to the clinical phenomenology of phantom limbs. With the advent of non-invasive imaging techniques such as MEG (magnetoencephalogram) and functional MRI, topographical reorganization (...) can also be demonstrated in humans, so that it is now possible to track perceptual changes and changes in cortical topography in individual patients. We suggest, therefore, that these patients provide a valuable opportunity not only for exploring neural plasticity in the adult human brain but also for understanding the relationship between the activity of sensory neurons and conscious experience. We conclude with a theory of phantom limbs, some striking demonstrations of phantoms induced in normal subjects, and some remarks about the relevance of these phenomena to the question of how the brain constructs a 'body image.'. (shrink)

Several recent lines of inquiry have pointed to the amygdala as a potential lesion site in autism. Because one function of the amygdala may be to produce autonomic arousal at the sight of a significant face, we compared the responses of autistic children to their mothers’ face and to a plain paper cup. Unlike normals, the autistic children as a whole did not show a larger response to the person than to the cup. We also monitored sympathetic activity in autistic (...) children as they engaged in a wide range of everyday behaviours. The children tended to use self-stimulation activities in order to calm hyper-responsive activity of the sympathetic (`fight or flight’) branch of the autonomic nervous system. A small percentage of our autistic subjects had hyporesponsive sympathetic activity, with essentially no electrodermal responses except to self-injurious behaviour. We sketch a hypothesis about autism according to which autistic children use overt behaviour in order to control a malfunctioning autonomic nervous system and suggest that they have learned to avoid using certain processing areas in the temporal lobes. (shrink)

This chapter presents the following hypothesis: There is a perfectly sensible conception of the mind, consciousness, the self, what we mean by ‘I,’ how we perceive and know, and how we remember and decide, all of which cohere amongst one another as well as with what we know about the brain, according to which it is possible for one person to experience directly the conscious states of another person. Not only can one person be directly aware of the conscious states (...) of another person, he can be more aware of them than their original owner. He can even be aware of them when their original owner will never be aware of them. Mindmelding is possible, and this possibility removes much of the force from the mind-body problem by removing the impasse caused by the belief in privacy. It removes what some philosophers saw as a need to posit strange metaphysical categories. The subject's sense of self can be separated from the object of her conscious awareness which can be bound to another's sense of self. (shrink)

Cases in which people are self-deceived seem to require that the person hold two contradictory beliefs, something which appears to be impossible or implausible. A phenomenon seen in some brain-damaged patients known as confabulation (roughly, an ongoing tendency to make false utterances without intent to deceive) can shed light on the problem of self-deception. The conflict is not actually between two beliefs, but between two representations, a 'conceptual' one and an 'analog' one. In addition, confabulation yields valuable clues about the (...) structure of normal human knowledge-gathering processes. [The hypothesis defended here is significantly altered and greatly expanded in my book Brain Fiction.]. (shrink)

This chapter explains how mindmelding — the direct experience by one person of another's conscious states — is in fact possible. The temporal lobes causally interact with the prefrontal lobes by way of fiber bundles that run underneath the cortical surface. This provides the perfect first experiment in mindmelding: to ‘branch’ those fiber bundles and run the other end into the brain of another person. Evidence is provided that these bundles have close connections to consciousness, in that whatever affects them (...) has immediate effects on consciousness. Then, before responding to several objections, the chapter considers another issue brought up by these experiments — the question of the relation between mindmelding and mindreading. Is mindmelding similar to mindreading? Does the existence of a mindreading system help us achieve mindmelding? (shrink)

Neurological syndromes in which consciousness seems to malfunction, such as temporal lobe epilepsy, visual scotomas, Charles Bonnet syndrome, and synesthesia offer valuable clues about the normal functions of consciousness and ‘qualia’. An investigation into these syndromes reveals, we argue, that qualia are different from other brain states in that they possess three functional characteristics, which we state in the form of ‘three laws of qualia’. First, they are irrevocable: I cannot simply decide to start seeing the sunset as green, or (...) feel pain as if it were an itch; second, qualia do not always produce the same behaviour: given a set of qualia, we can choose from a potentially infinite set of possible behaviours to execute; and third, qualia endure in short-term memory, as opposed to non-conscious brain states involved in the on-line guidance of behaviour in real time. We suggest that qualia have evolved these and other attributes because of their role in facilitating non-automatic, decision-based action. We also suggest that the apparent epistemic barrier to knowing what qualia another person is experiencing can be overcome by using a ‘bridge’ of neurons; and we offer a hypothesis about the relation between qualia and one's sense of self. (shrink)

The emerging neuroscience of psychopathy will have several important implications for our attempts to construct an ethical society. In this article we begin by describing the list of criteria by which psychopaths are diagnosed. We then review four competing neuropsychological theories of psychopathic cognition. The first of these models, Newman’s attentional model, locates the problem in a special type of attentional narrowing that psychopaths have shown in experiments. The second and third, Blair’s amygdala model and Kiehl’s paralimbic model represent the (...) psychopath’s problem as primarily emotional, including reduced tendency to experience fear in normally fearful situations, and a failure to attach the proper significance to the emotions of others. The fourth model locates the problem at a higher level: a failure of psychopaths to notice and correct for their attentional or emotional problems using “executive processes.” In normal humans, decisions are accomplished via these executive processes, which are responsible for planning actions, or inhibiting unwise actions, as well as allowing emotions to influence cognition in the proper way. We review the current state of knowledge of the executive capacities of psychopaths. We then evaluate psychopaths in light of the three major philosophical theories of ethics, utilitarianism, deontological theory, and virtue ethics. Finally, we turn to the difficulty psychopath offenders pose to criminal law, because of the way psychopathy interacts with the various justifications and functions of punishment. We conclude with a brief consideration of the effects of psychopaths on contemporary social structures. (shrink)

In this chapter we will argue that the capacities necessary to moral and legal agency can be understood as executive functions in the brain. Executive functions underwrite both the cognitive and volitional capacities that give agents a fair opportunity to avoid wrongdoing: to recognize their acts as immoral and/or illegal, and to act or refrain from acting based upon this recognition. When a person’s mental illness is serious enough to cause severe disruption of executive functions, she is very likely to (...) lack substantial capacities necessary to be law-abiding. Our analysis supports the Model Penal Code test for legal insanity over the traditional M’Naghten test, because the Model Penal Code test allows either severely diminished cognitive or volitional capacities to warrant an excuse to criminal culpability. We will provide a nuanced account of the ways in which mental illness can erode executive function, as well as an explanation as to why severe diminishment of executive functions caused by mental illness, but not some other causes, is exculpatory. (shrink)

This chapter shows that mindmelding is metaphysically possible, i.e., that it does not violate any laws governing the metaphysical nature of reality. Metaphysical issues are fundamental and lie at the core of the most difficult parts of the problems of privacy and the mind-body problem itself. There is nothing stopping us from placing the idea of mindmelding on clear, unproblematic, and plausible metaphysical foundations. It is argued that the position of privacy is the one on shaky metaphysical grounds. Two metaphysical (...) theses are examined: the thesis of privacy, and the idea that all conscious states must have a subject, which is called ‘inseparability’ because it posits that the subject is inseparable from the conscious state. (shrink)

Recent evidence points to widespread underconnectivity in autistic brains owing to deviant white matter, the fibers that make long connections between areas of the cortex. Subjects with autism show measurably fewer long-range connections between the parietal and prefrontal cortices. These findings may help shed light on the current debate in the consciousness literature about whether conscious states require both prefrontal and parietal/temporal components. If it can be shown that people with autism have conscious states despite such underconnectivity, this would constitute (...) an argument for the claim that conscious states can exist in posterior cortex without associated prefrontal activity. This in turn lends support to a class of theories according to which microconsciousness is possible—consciousness in small areas of cortex without active connections to the prefrontal cortex, as opposed to the higher-order thought (HOT) theory of consciousness, according to which conscious states can only occur when posterior cortical areas (in the parietal or temporal lobes) have active connections to the prefrontal cortex. In this chapter, after listing several candidate examples of consciousness without accompanying prefrontal connections, I will argue that autism provides yet another such example. I will also examine a recent version of the higher-order theory that acknowledges these cases of consciousness without prefrontal activity and, instead depicts consciousness as requiring higher-order thoughts located in posterior cortex. In the final section, I will examine the consequences of these views for our understanding of the metaphysical nature of consciousness itself—the classic mind-body problem. (shrink)

The cases that Doris chronicles of confabulation are similar to perceptual illusions in that, while they show the interstices of our perceptual or cognitive system, they fail to establish that our everyday perception or cognition is not for the most part correct. Doris's account in general lacks the resources to make synchronic assessments of responsibility, partially because it fails to make use of knowledge now available to us about what is happening in the brains of agents.

One of the final obstacles to understanding consciousness in physical terms concerns the question of whether conscious states can exist in posterior regions of the brain without active connections to the brain's prefrontal lobes. If they can, difficult issues concerning our knowledge of our conscious states can be resolved. This paper contains a list of types of conscious states that may meet this criterion, including states of coma, states in which subjects are absorbed in a perceptual task, states in brains (...) with damaged prefrontal lobes, states of meditation and conscious states of some infants and animals. Recent evidence also suggests that conscious states of some people with autism may meet this criterion. (shrink)

Child soldiers, who often appear to be both victims and perpetrators, present a vexing moral and legal challenge: how can we protect the rights of children while seeking justice for the victims of war crimes? There has been little stomach, either in domestic or international courts, for prosecuting child soldiers—but neither has this challenge been systematically addressed in international law. Establishing a uniform minimum age of criminal responsibility would be a major step in the right direction; we argue that such (...) a standard ought to be guided by the best evidence from neuropsychology about the development, during childhood and adolescence, of the executive functions that give rise to morally and legally responsible agents. In light of that evidence, which suggests that the brain’s executive functions are still maturing into early adulthood, we recommend a graded structure of culpability for child soldiers. (shrink)

[This is a response to a target article in BBS]. Although the art-historical context of a work of art is important to our appreciation of it, it is our knowledge of that history that plays causal roles in producing the experience itself. This knowledge is in the form of memories, both semantic memories about the historical circumstances, but also episodic memories concerning our personal connections with an artwork. We also create representations of minds in order to understand the emotions that (...) artworks express. (shrink)

This paper examines Todd Feinberg's theory of the misidentification syndromes.

Cognitive Science is a major new guide to the central theories and problems in the study of the mind and brain. The authors clearly explain how and why cognitive science aims to understand the brain as a computational system that manipulates representations. They identify the roots of cognitive science in Descartes - who argued that all knowledge of the external world is filtered through some sort of representation - and examine the present-day role of Artificial Intelligence, computing, psychology, linguistics and (...) neuroscience. Throughout, the key building blocks of cognitive science are clearly illustrated: perception, memory, attention, emotion, language, control of movement, learning, understanding and other important mental phenomena. Cognitive Science: presents a clear, collaborative introduction to the subject is the first textbook to bring together all the different strands of this new science in a unified approach includes illustrations and exercises to aid the student. (shrink)

Contrary to the widely-held view that our conscious states are necessarily private (in that only one person can ever experience them directly), in this paper I argue that it is possible for a person to directly experience the conscious states of another. This possibility removes an obstacle to thinking of conscious states as physical, since their apparent privacy makes them different from all other physical states. A separation can be made in the brain between our conscious mental representations and the (...) executive processes that manipulate them and are guided by them in planning and executing behaviour. I argue here that these executive processes are also largely responsible for producing our sense of self in the moment. Our conscious perceptual representations themselves reside primarily in the posterior portions of the brain's cortex, in the temporal and parietal lobes, while the executive processes reside primarily in the prefrontal lobes. We can imagine an experiment in which we sever the association fibers that connect the posterior regions with these prefrontal regions and, instead, connect the posterior regions to the prefrontal regions of another person. According to my hypothesis, this would produce in the latter person the direct experience of the conscious perceptual states of the first person. (shrink)

This brief text assists students in understanding Searle's philosophy and thinking so they can more fully engage in useful, intelligent class dialogue and improve their understanding of course content. Part of the Wadsworth Notes Series, (which will eventually consist of approximately 100 titles, each focusing on a single "thinker" from ancient times to the present), ON SEARLE is written by a philosopher deeply versed in the philosophy of this key thinker. Like other books in the series, this concise book offers (...) sufficient insight into the thinking of a notable philosopher, better enabling students to engage in reading and to discuss the material in class and on paper. (shrink)

According to several current theories, executive processes help achieve various mental actions such as remembering, planning and decision-making, by executing cognitive operations on representations held in consciousness. I plan to argue that these executive processes are partly responsible for our sense of self, because of the way they produce the impression of an active, controlling presence in consciousness. If we examine what philosophers have said about the "ego" (Descartes), "the Self" (Locke and Hume), the "self of all selves" (William (...) James), we will find that it fits what is now known about executive processes. Hume, for instance, famously argued that he could not detect the self in consciousness, and this would correspond to the claim (made by Crick and Koch, for instance) that we are not conscious of the executive processes themselves, but rather of their results. (shrink)

Our love for art is a compound byproduct of four different evolutionary events which attached reward to conscious experience itself, to the direction of attention to significant items in consciousness, to representations of scenarios in the brain's default mode network, and to the experience of novel stimuli. Aesthetic experiences contain varying amounts of these rewards, which helps to explain their diversity.

Presenting an engaging overview of the Churchlands that is accessible to undergraduate philosophy students and general readers, this title-a volume in the Wadsworth Philosophy Topics Series--provides a concise introduction to this pertinent topic of philosophical interest. The Wadsworth Philosophy Topics Series presents readers with concise, timely, and insightful introductions to a variety of traditional and contemporary philosophical subjects. With this series edited by Daniel Kolak of the William Paterson University of New Jersey, philosophy students will be able to discover (...) the richness of philosophical inquiry across a wide array of concepts, including hallmark philosophical themes and topics typically underrepresented in mainstream philosophy publishing. Written by a distinguished list of scholars who have been noted for their exceptional teaching abilities, this series presents the vast sweep of today's philosophical exploration in highly accessible and affordable volumes. These books will prove valuable to philosophy teachers and their students as well as to other readers who share a general interest in philosophy. (shrink)

Neurological syndromes in which consciousness seems to malfunction, such as temporal lobe epilepsy, visual scotomas, Charles Bonnet syndrome, and synesthesia offer valuable clues about the normal functions of consciousness and ‘qualia’. An investigation into these syndromes reveals, we argue, that qualia are different from other brain states in that they possess three functional characteristics, which we state in the form of ‘three laws of qualia ’ based on a loose analogy with Newton’s three laws of classical mechanics. First, they are (...) irrevocable: I cannot simply decide to start seeing the sunset as green, or feel pain as if it were an itch; second, qualia do not always produce the same behaviour: given a set of qualia, we can choose from a potentially infinite set of possible behaviours to execute; and third, qualia endure in short-term memory, as opposed to non-conscious brain states involved in the on-line guidance of behaviour in real time. We suggest that qualia have evolved these and other attributes (e.g. they are ‘filled in’) because of their role in facilitating non-automatic, decision-based action. We also suggest that the apparent epistemic barrier to knowing what qualia another person is experiencing can be overcome simply by using a ‘bridge ’ of neurons; and we offer a hypothesis about the relation between qualia and one’s sense of self. (shrink)

The psychological literature now differentiates between two types of psychopath:successful (with little or no criminal record) and unsuccessful (with a criminal record). Recent research indicates that earlier findings of reduced autonomic activity, reduced prefrontal grey matter, and compromised executive activity may only be true of unsuccessful psychopaths. In contrast, successful psychopaths actually show autonomic and executive function that exceeds that of normals, while having no difference in prefrontal volume from normals. We argue that many successful psychopaths are legally responsible for (...) their actions, as they have the executive capacity to choose not to harm (and thus are legally rational). However, many unsuccessful psychopaths have a lack of executive function that should at least partially excuse them from criminal culpability. Although a successful psychopath's increased executive function may occur in conflict with, rather than in consonance with their increased autonomic activity - producing a cognitive style characterized by self deception and articulate-sounding, but unsound reasoning - they may be capable of recognizing and correcting their lack of autonomic data, and thus can be held responsible. (shrink)

US criminal courts have recently moved toward seeing juveniles as inherently less culpable than their adult counterparts, influenced by a growing mass of neuroscientific and psychological evidence. In support of this trend, this chapter argues that the criminal law’s notion of responsible agency requires both the cognitive capacity to understand one’s actions and the volitional control to conform one’s actions to legal standards. These capacities require, among other things, a minimal working set of executive functions—a suite of mental processes, mainly (...) realized in the prefrontal cortex, such as planning and inhibition—which remain in significant states of immaturity through late adolescence, and in some cases beyond. Drawing on scientific evidence of how these cognitive and volitional capacities develop in the maturing brain, the authors sketch a scalar structure of juvenile responsibility, and suggest some possible directions for reforming the juvenile justice system to reflect this scalar structure. (shrink)