The violence inhibition mechanism in humans

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The full article with all sources can be found on the main page: https://antiviolence.io/en/#violence_inhibition_mechanism

How inhibition of intraspecific aggression functions in the case of humans can be explained by resorting to the Violence Inhibition Mechanism (VIM) model. Based on the conclusions of Konrad Lorenz and Irenaus Eibl-Eibesfeldt that many animal species have inhibitors of intraspecific aggression developed in the course of biological evolution, the neuroscientist James Blair suggested the presence of such inhibitors in humans, proposing the VIM model. In developing this model, he also pursued the goal of explaining the emergence of psychopathy as a result of a malfunction of this mechanism.

VIM is a cognitive mechanism that is directly activated in humans by non-verbal distress cues from other humans, such as a sad facial expression or crying. This causes an aversive reaction, and the stronger the distress signal, the stronger the corresponding reaction: a slight sadness on the face will cause only partial aversion, but screams and sobbing can completely stop the aggressor.

As studies show, the observation of distress cues does induce a physiological response in the form of such a reaction. This reaction can be observed from a very early age. Infants aged 2-3 days cry to the sound of crying, and this reactive crying is not simply a response to noxious auditory stimuli; infants do not cry to equally loud and intense non-human sounds.

Evidence of this kind can be used to explain empathy – the ability to understand the feelings and state of other people regarding oneself, so it is necessary to find out how it is related to VIM. Moreover, VIM is not just a mechanism that causes an unconditioned reflex (aversive reaction) to an unconditioned stimulus (distress cues). Blair argues that through the process of conditioning (the formation of conditioned reflexes) it becomes a cognitive prerequisite for the development of three aspects of morality: the moral emotions (i.e., sympathy, guilt, remorse, and empathy), the inhibition of violence, and the ability to distinguish between moral and conventional transgressions.

During development, individuals are faced with the fact that distress cues from other people cause VIM activation. This is an unconditioned reflex to an unconditioned stimulus. At the same time, they can often try on the role of the victims in order to understand their state. In this way, an association of the distress signal that activates the VIM with the state of the victim is formed. This association becomes the conditioned stimulus for the conditioned reflex. As a result, the individual becomes able to show an empathic response only by thinking about someone else's distress. In line with this, film sequences where the victims of violence talked about their experience, while not showing any distress cues, evoked a corresponding physiological reaction in the audience.

The inhibition of violence works similarly. As early as childhood (even at the age of 4-7 years), normally developing individuals will experience an activation of the VIM and aversive reaction due to distress cues emitted by the victims as soon as they might attempt to commit an act of violence. Over time, even the very thought of committing violence will begin to lead to this reaction, and the probability that an individual will behave violently will gradually decrease.

The activation of VIM also acts as a mediator in distinguishing between moral and conventional transgressions. Although, in order to do so, it is necessary to first gain experience demonstrating moral transgressions – actions consisting in causing harm to people. The association of moral transgressions with subsequent distress cues from victims will eventually lead to the development of a conditioned reflex that activates VIM. In turn, social transgressions that do not lead to harm but only consist in violating established social norms will not be associated with distress cues, which means that the corresponding experience will not lead to the development of a conditioned reflex. This is how the individual becomes capable of identifying moral transgressions in actions.

Of course, individuals without VIM can evaluate a moral transgression as a bad act if someone tells them that it is bad. However, in their assessment, they will refer to the words of other people without experiencing an aversive reaction from causing harm in reality. Perhaps with a favorable upbringing, a good social environment, and the absence of provoking factors, they will not commit violence. But no inner inhibitors, in comparison with normally developing individuals, will prevent them from doing this.

To support the validity of his model, Blair cites the results of many studies. Children with a predisposition to psychopathy and adult psychopaths do show a poor ability to distinguish between moral and social transgressions. The same applies to children with conduct disorder. In addition, and in line with the VIM position, adult psychopaths show reduced comprehension of situations likely to induce guilt, although they show appropriate comprehension of happiness, sadness, and even complex social emotions such as embarrassment. Moreover, and a direct prediction of the VIM model, children and adults with psychopathy show pronounced impairment in processing sad and fearful facial and vocal expressions. What is important to note is that the ability to distinguish between moral and social transgressions is not associated with a bad upbringing and abuse in childhood.

Many other studies also support this model. For example, aggressiveness from Callous and Unemotional traits (abbr. CU-traits) is associated with poor ability to recognize fearful facial expressions and fearful body postures. Children with high scores of CU-traits also experience problems with recognizing expressions of sadness, and children with high scores of conduct disorder with recognizing expressions of fear. Schizophrenics with a history of violent crime differ from non-violent schizophrenics in their lower ability to recognize facial expressions, especially expressions of fear. Finally, people with high affective psychopathy scores were found to be less able to distinguish genuine distress cues from staged ones. At the same time, this effect did not extend to other emotions, such as happiness, anger, or disgust; it was specific to distress cues. Many other studies show similar results and therefore confirm the validity of the VIM model.

Finally, it is worth noting that psychopathy as a result of the malfunction of the VIM is a mental disorder by Wakefield's criteria. According to these criteria, a condition is a disorder if it is negatively valued (as "harmful") by sociocultural standards, and it is in fact due to a failure of some internal mechanism to perform a function for which it was biologically designed (i.e., naturally selected).

Of course, the VIM model does not provide a complete explanation of the nature of aggression regulation, which is why Blair later expanded it and developed the Integrated Emotion System (IES) model, which considers the neurophysiological aspects of this process. However, it still confirms the presence of restraints on intraspecific aggression in humans and gives a general idea of how they work.