Neurobiology of moral behavior: Part I

Overview

The discussion on morality is often confused by religious doctrine and language in the debate arena; however, in communication between believers and non-believers this subject invariably will arise. There is no ultimate arbiter of morality, we define the terms, and Sam Harris defines morality as a measure of well being, which is a reasonable term; however, there are other scientific determinates for this although by no means are there universal appraisals or worldwide accepted quantifiers. This is a brief overview of the neurobiology of moral behavior as opposed to a philosophical construct of ‘morality’, which is more difficult to define, quantify, or qualify, with moral behavior being more identifiable a characteristic or set of traits.

Morality and ethics are to a degree different constructs, albeit these are related topics, and they tend to be frequently amalgamated in discourse. For the purposes of this article, I will only discuss the general subject of morality as this relates to neuroscience and developmental research.

Part I of this writing speaks to the review of the literature on the neurobiology of moral behavior, as this relates to evolutionary theory and developmental studies; Part II will include fMRI, neurochemistry, and medical model research. Each part will include brief descriptions of the data for the non-neuroscientist.   Morality is broadly described in the literature as an evolutionary construct and as a code of values that determines beneficial prosocial behavior, such as adopting the rule “do no harm” for example.

Evolution and Prosocial behavior in children

Morality or prosocial behavior is automatic in our species and there are mechanisms identified in our brains that are consistent with our evolutionary history and our survival within socially cooperative groups. Our species evolved emotions against harming others, a sense of fairness, and rule enforcement, as well as empathy, and other related behaviors, including theory of mind, which is the emotional ability to understand the thoughts and feelings of another.

With respect to dishonest behavior and from and evolutionary perspective, “despite the evolution of social mechanisms to deter antisocial ‘cheating’ behavior, it has been argued that antisocial behavior is an evolutionary stable strategy—a pre-programmed behavioral approach that maximizes reproductive fitness. Psychopathy has been viewed as the full expression of this ‘cheating’ strategy. One prediction generated by this model is that antisocial and psychopathic individuals would manifest impairments in the brain mechanism requisite for morals, particularly those neural processes critical to the experiencing of moral emotions.” (Adrian Raine and Yaling Yang  2006).

Psychopathy, also called sociopathy may manifest originally in childhood although prior to the age of 18, the term applied is conduct disorder with a decidedly different set of behaviors and traits developmentally. The studies reviewed for this writing in non-prosocial individuals are limited to adults with psychopathy and which will be addressed in more detail in Part II.

Babies have an innate sense of empathy or at least, of what is right and wrong. For example, infants shown puppet shows depicting scenes of objects helping or hindering another object encourages a baby to chose the puppet that did the helping, and reject the puppet that did the hindering, all other factors controlled, and “human babies, notably, cry more to the cries of other babies than to tape recordings of their own crying, suggesting that they are responding to their awareness of someone else’s pain, not merely to a certain pitch of sound. Babies also seem to want to assuage the pain of others: once they have enough physical competence (starting at about 1 year old), they soothe others in distress by stroking and touching or by handing over a bottle or toy. “suggesting an innate rudimentary theory of mind and state of empathy from early on. (Bloom, P. Feb. 2008)

Other social primates exhibit what would normally be described as moral emotions, such as empathy, gratitude, fairness, reciprocity, righteousness, consolation, and group loyalty; humans are not unique in these characteristics, and human children begin prosocial behavior at least by the age of two years.

One study explored the meaning of the changes behind this behavior through the toddler years in three domains, as in action based (instrumental), emotion based (empathic), and costly (altruistic) behaviors.  The youngsters in the study were aged 18-30 months, exhibited these behaviors increasingly in each subsequent older age group, respectively, and the degrees of helping behavior was not dependent upon demographics, suggesting that this is not a learned or cultural phenomenon but a normal part of development. This replicates what Paul Bloom and others have shown about babies and toddlers in past research on this subject with respect to prosocial behaviors. (Margarita Svetlova, Sara R. Nichols, and Celia A. Brownell 2011)

There is much to learn from the adolescent brain, given that these youngsters are prone to “an increased incidence of unintentional injuries, violence, substance abuse, unintended pregnancy, and sexually transmitted diseases…[when] approximately 70% of these deaths result from motor vehicle crashes, unintentional injuries, homicide, and suicide,” and when impulse control is immature cross-culturally, given that this is a normal developmental stage, we may learn something about the development of moral behavior in our species.

Some theorists have postulated that the dopaminergic mesolimbic circuitry, implicated in reward processing, underlies risky behavior”  (B.J. Casey, Rebecca M. Jones, and Todd A. Hare, 2006) This suggests that developmentally, adolescence is a time where neuroanatomically and neurochemically, a time of reorganization of the central nervous system and myelination, reinforcement and reward is a highly important phenomenon occurring between brain and behavior, potentially a period of growth and remodeling between innate morality in the dopaminergic mesolimbic structures and environmental factors include emotional states.

During late adolescence, the brain reorganization appears to parallel improved self-control and moral behaviors as the adolescence progresses.  The changes shift activation from diffuse prefrontal areas to more localized regions over time, and increased recruitment of regions beneath the cortex (called “subcortical”) during adolescence as a part of the maturation process. How much of these structural change are related to specifically to risk taking, reward processing, and emotional reactivity in this developmental populations is unknown at present. Additionally, “adolescents knowingly engage in risky behavior, and this is often due to influences of feelings, emotions, and peers; the adolescent is capable of making rational decisions, but in emotionally charged situations the more mature limbic system will win over the prefrontal control system. Adolescents make more rational decisions about hypothetical scenarios over real-life situations. “ (B.J. Casey, Rebecca M. Jones, and Todd A. Hare, 2006)

Discussion

There is quite a lot of information on the neurobiology of moral behavior, so much so that this writing requires two sections each for brevity sake. In this section, we’ve addressed the issue as to what degree the morality construct is innate and to what degree this is environmental in particular during infancy and the adolescent years during central nervous system reorganization; however, from research in this area, it is increasingly clear that we are neurologically hard-wired or primed toward prosocial behavior from early on in infancy and childhood, developmentally.

Environment may shape our innate moral or prosocial behaviors, however it is rather unmistakable that we are born with these traits, similar to our other primate cousins. It is unlikely that we would have survived to reproduce without moral behavior characteristics, or we would have evolved in a much different fashion had we not been a prosocial and cooperative species.

In Part II we will explore the neuroanatomical and neurochemical studies in current research, and medical models available on the subject of the neurobiology of moral behavior.