The Moral Brain introduces its reader to a fascinating array of experiments and implications for philosophy, psychology, and law enforcement, and is a worthwhile read for students and lay professionals interested in what contemporary neuroimaging can teach us about human moral thought.  It is written to be accessible to a variety of audiences, but it does require some prior understanding of neuroanatomy and evolutionary biology as well as basic ethical theories.  The heart of the text concerns what the activation of specific structures in the brain can tell us about moral reasoning.  Given the brain’s complexity, it is not surprising to find that these structures don’t always function harmoniously, producing different behavioral outcomes and moral judgments.  The result is a fascinating account for why we act the way that we do, up to and including aberrant psychopathological behavior.

          The book is divided into six sections, each raising issues worthy of their own full-length treatments. The first section concerns morality and evolution, drawing on animal studies exploring altruistic and prosocial behavior and discussing how traits like empathy and fairness may have evolved.  The text then discusses the motivation to act morally, including discussions of reason and emotion, as well as self-identification with groups and concepts (providing some insight into how people can make decisions that sacrifice their personal good for a collective or ideological good).  It then transitions into how morality may have developed, looking at apparently hard-wired behaviors in infants and children in the context of cultural relativism — there seem to be elements of moral thought that are both universal and susceptible to cultural variations.  For instance, children may have an inherent sense of fairness and preferentially favor prosocial actions which are tweaked and refined by individual cultural contexts.  The work then shifts to discussions of affective and social neuroscience, looking at specific structures in the brain that are active when making moral decisions (and internal/external factors that can change how these structures behave), and is followed by an exploration of psychopathological behavior — what happens when these structures don’t function normally.  This leads to the final section of the book, which explores how these findings can alter our understanding of justice and law — if we understand aberrant behavior to have an underlying neuropsychological cause, we are forced to reevaluate how we view punishment and moral responsibility.  We may still hold people legally responsible for their actions, but it may mitigate our moral judgments of wrongdoing.

          There are a number of important elements to stress at this point.  First, while the book discusses neuroanatomy and moral choices, it is not merely making reductive arguments.  It is important to note that there isn’t one single “moral center” — moral behaviors are actually the result of a number of different brain regions operating and communicating with one another, sometimes cooperating and sometimes conflicting.  So while the text does discuss brain regions implicating empathic ties to others, emotional responses to moral questions or disgusting statements, or parental bonding with children, it does not tell us where exactly moral reasoning lies.  Morality is a system-level behavior — more than the sum total of its parts.  This has interesting implications for ethical theory and philosophy, which are discussed below.

The text makes some assumptions about its reader’s understanding of neuroanatomy — this is not a text to approach if you are unfamiliar with neurobiology (for instance, how neurons talk to each other or how the brain is divided and described).  Many authors discuss specific structures in the fore- and midbrain in technical language — some readers may need to keep an anatomy textbook nearby when the authors shift from commonly known structures like the amygdala and begin to reference less well known structures to the laity like the ventromedial prefrontal cortex (vmPFC).  I encourage visual learners to review the diagrams thoughtfully included in de Oliveira-Souza, Zahn, and Moll’s chapter which label regions frequently mentioned in their (and others’) contribution, as general readers will benefit from understanding the relationship between the vmPFC, frontopolar cortex (FPC), right anterior temporal lobe, hypothalamus, subgenual cortex, and amygdala (among many others).  These structures are important for discussions about moral behaviors both within the text as well as within larger fields like biopsychology and neuroethics — especially when discussions shift towards sociopathy and predatory behavior.  These behavioral elements are especially relevant in sections describing animal studies and psychopaths.

          In addition to some basic assumptions about the reader’s understanding of neuroanatomy, the text makes some assumptions about the reader’s philosophical knowledge, specifically regarding ethical theories like deontology and utilitarianism.  Several chapters discuss a well-known thought experiment in ethics called the Trolley Problem.  Briefly, a trolley is running out of control down a track on which there are five people.  There is also a track that joins with this one on which there is only one person, and a switch that will force the trolley onto the alternate track.  If the moral agent does nothing, the trolley will continue on to kill the five people, but if the agent pulls the switch only one will die, forcing the agent to choose between a death by commission or omission.  A variation on this problem introduces a fat man who the agent could push onto the track to stop the trolley instead of providing a switch to throw (making the decision more personal and visceral).  The problem is one of a deontological respect for the individual (not killing the one directly) versus utilitarian concern for the greater good (not killing the many indirectly).  The chapters in question note the different brain regions that activate when one is weighing one philosophy versus another — the structures associated with emotional processing activate when we are considering the plight of the individual while structures associated with weighing consequences and dispassionate analysis activate when considering utilitarian approaches.

          This raises interesting questions for future research about neuroanatomical correlates of ethical theories.  The activation of both emotional and rational thought regions suggests moral modeling akin to David Hume’s sentimentalism (which draws upon both emotional content for moral force and rational reflection as a means to attain moral principles), and it would be interesting to note if other ethical systems present either unique or overlapping neural activation.  Ethics is a complex field and a number of methodologies are represented beyond simple utilitarian and deontological philosophies.  It would be interesting, for instance, if future research explored whether moral systems like virtue ethics involve activation of reward pathways (in light of its dependence on moral habituation, does it literally feel good to do good) or do systems like care ethics activate centers involved with empathy more than deontological systems (given its emphasis on relationships and interdependence)?  Regretfully, these are questions for future research and not the current text.

There are additional questions raised in the course of the readings.  Empathy, for instance, is generally and noncontroversially regarded as a desirable trait in a moral agent.  But what if empathy was an evolutionary mechanism to foster in-group/out-group survival?  Provocatively, Joshua Greene’s chapter includes the suggestion that morality evolved not to foster cooperation, but as a weapon designed to maximize the survival of the agent’s in-group (Us) by out-competing the out-group (Them).  Additionally, several chapters provide evidence to those who would argue against free will — multiple factors impact how we make complex moral decisions, up to and including whether we are hungry when we make the decision, and these are not always factors that make a conscious impression on us.  Free will would seem to be a prerequisite for moral responsibility — we tend to hold people responsible for their actions only when they could have done something else.  Absent that freedom to do otherwise, moral praise or blame don’t make much sense.

          As an ethicist, this text strikes home, particularly in light of the evidence presented for normal moral agency involving both rational and emotional content.  Some of the evidence is not surprising — we have recognized the importance of emotional memory in making good decisions (see, for instance, Antonio Damasio’s Descartes’ Error) and the lack of emotional engagement and empathy in psychopathy, but the extent to which we integrate reason and emotion at a conscious and unconscious level is fascinating.  Hume was certainly ahead of his time, and he can be forgiven the neuroanatomy and processing details absent in 18^th century Edinburgh.  The Moral Brain gives us a compelling and modern take, providing biological details and history that both reduce and enrich the complex phenomenon that is moral thought.

© 2015 Matthew A. Butkus

Matthew A. Butkus, PhD, Associate Professor – Philosophy, McNeese State University, LA