The frontal lobes of the human brain are the seat of moral consciousness. It is here, amidst the synapses and neurotransmitters, that our moral sense resides. How do we know this? The short answer is by studying behavior in those individuals who have suffered traumatic injury to this area of the brain.
Take the curious case of Phineas Gage, a 19th century railroad worker who suffered a bizarre accident when a 3-foot long iron tamping bar blasted through his left cheek and exited his skull at the midline near the top of his head. Both frontal lobes were damaged in the incident. Remarkably, Gage was able to walk and speak immediately after the accident. Although he continued to live an additional 12 years, his coworkers noted marked changes in his behavior.
His contractors, who regarded him as the most efficient and capable foreman in their employ previous to his injury, considered the change in his mind so marked that they could not give him his place again. He is fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom), manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires, at times pertinaciously obstinate, yet capricious and vacillating, devising many plans of future operation, which are no sooner arranged than they are abandoned in turn for others appearing more feasible. In this regard, his mind was radically changed, so decidedly that his friends and acquaintances said he was “no longer Gage.”
The executive function of Phineas Gage’s prefrontal cortex had deteriorated as a result of the trauma.
Similar behavioral changes are apparent in those addicted to various substances, such as alcohol or opiates.
As dependence grows, alcoholics also lose the ability to properly regulate their behavior. This regulation is the responsibility of the prefrontal cortex, which is charged with keeping the rest of the brain apprised of the consequences of harmful actions. But mind-altering substances slowly rob the cortex of so-called synaptic plasticity, which makes it harder for neurons to communicate with one another. When this happens, alcoholics become less likely to stop drinking, since their prefrontal cortex cannot effectively warn of the dangers of bad habits.
Because the synapses in their prefrontal cortex are still damaged, they have a tough time resisting the urges created by these triggers.
According to Stefan G. Hofmann, professor of psychology at Boston University, “As we grow, the prefrontal areas of the brain develop, and we become more biologically able to control our impulses.”
Impaired executive functions, apathy, and impulsivity are hallmarks of frontal-subcortical circuit dysfunction. Personality changes from orbitofrontal damage include impulsiveness, puerility, a jocular attitude, sexual disinhibition, and complete lack of concern for others. A lack of empathy or an inability to infer the mental state of others leads to inappropriate behavior.
An interesting sidelight here is that these sorts of behaviors—lack of empathy or an inability to infer the mental state of others—are seen in autistic individuals, who may lack a sufficient number of mirror neurons, those cells that allow us to imagine the feelings of others.
Cellular synapses might ultimately determine the moral state of the human soul.