Neurobiologists have put forward two neurological models that can be used to understand the development of social behavior; the Violence Inhibition Mechanism, and the Somatic Marker Hypothesis.
The Violence Inhibition Mechanism (VIM)
The VIM was first proposed by R.J.R Blair in 1995 in his article A cognitive developmental approach to morality: Investigating the psychopath. The VIM proposes that individuals (and other organisms capable of empathy) experience stress cues from others, including sad and frightened faces, and these are filtered/processed through the VIM before the individual’s stress response is activated. Our sense of morality also causes an emotional experience based upon the observance of these stress cues, and the VIM again processes behavioral outcomes before they arise.
In his book The Psychopath: Emotion and the Brain, Blair states that the observance of another’s suffering acts as a form of punishment, which in turn decreases the likelihood of engaging in behavior that caused the suffering (the psychological definition of punishment, unlike reinforcement, is something that results in the decrease of the behavior in question). Empathy, then, creates an emotional experience that should dissuade a person from engaging in acts that cause the suffering of others. If it was violence that resulted in the suffering, the VIM should prevent a repeat of this violence.
This model seems contingent on an observer empathizing with the victim, rather than the aggressor. While empathizing with the victim does seem the most honorable and obvious, if the benefits and pleasure obtained by the aggressor seem desirable, the aggressor’s behavior could reinforce the behavior in question.
Somatic Marker Hypothesis
The somatic marker hypothesis was proposed by Antonio Damasio in his book Descartes’ Error: Motion, Reason, and the Human Brain. This hypothesis is built on the idea that emotional states or feelings mark certain behaviors from experience (and presumably from witnessing the behavior of others), and this is crucial for understanding prosocial behavior and making good decisions.
When a person experiences arousal (positive or negative), the central nervous system becomes active, and communication between brain stem nuclei and the limbic system generate an internal emotional state. These emotional states become tagged to the memories of what the organism was experiencing at a specific time, and are thus re-created when the organism remembers the experience. This emotional re-creation allows us to learn from experience.
It has been argued that psychopaths, who seem to suffer from some kind of affective blunting, are unable to tag memories with or experience emotions that are common to most of us. As the psychopathic brain develops, therefore, the individual is unable to learn right and wrong like the rest of us, and can only approach the subject from an emotionless logical perspective. The brain areas involved in producing these crucial markers (incl. the amygdala, the orbitofrontal & ventromedial prefrontal cortices, and the cingulate) are often found to be dysfunctional or mal-developed in the antisocial brain.