Violence in our brains, neurochemistry, and genes

Violence in our Brains, Neurochemistry, and in our Genes

Humans are wired for violence and aggression. We know from the historical roadmap

that violence has been found in nearly every-known human society. We know that violent,

aggressive tendencies are embedded in our neural networks, neurochemistry, and genetic

blueprint. There are many structures, transmitters, and modulators in the human brain that are

associated with emotions such as anxiety, stress, aggression, and violence. None act alone and it is

not possible to review all of them in this introduction. However, some of the more important

have to do with our brain’s activation and wiring in our prefrontal cortex, including the orbital

cortex, ventral medial Prefrontal Cortex (vmPFC), Dorsolateral Prefrontal cortex (dlPFC), Insula,

Amygdala, and Limbic region. Neurochemicals that are important to consider are serotonin,

testosterone, vasopressin, and oxytocin. Optimal functioning of the PFC is critical. Studies show

that “criminal psychopaths have decreased activity in the frontal cortex and less coupling of the

PFC to other brain regions (compared with nonpsychopathic criminals and noncriminal

controls)” (Sapolsky, 2017, p. 54). In agreement, Dozier (2002, p.137) has found that a number of

studies show that:

“The more densely wired the orbitofrontal cortex, the more that hate and violence in males is suppressed. The orbitofrontal cortex – part of the massive human prefrontal cortex – is the area that gives us our capacity for empathyadvanced impulse control. When men and women live together and raise their children together in an equal setting, the men tend to activate this empathy center much more frequently as they interact with their wives and children. And this empathetic attitude towards other men tends to strongly influence their sons.”

Citing the work of several studies, Sapolsky (2017, p. 76) reports that low levels of the

neurotransmitter serotonin are, “associated with elevated levels of human aggression, with end

points ranging from psychological measures of hostility to overt violence.” Research further

shows that when stress, difficult living conditions, and a harsh upbringing are combined,

serotonin levels plunge (Howard, 2014). The hormone testosterone is highly implicated in

aggression and violence. However, “some male aggression is testosterone independent,” meaning

that even after “testosterone and androgens are completely eliminated, some aggression remains”

(Sapolsky, 217, p. 100). Finally, the hormone, oxytocin, sometimes referred to as the love

hormone also plays a role in human aggression, violence, and helpful behavior. Oxytocin

suppresses “fear and anxiety, and activates the ‘calm, vegetative parasympathetic nervous

system,” (p. 112) which decreases blood pressure, heart rate, and induces a state of calm.

However, there is also a “darkside” to oxytocin. Some studies show that “oxytocin makes you

more prosocial to people like you…but spontaneously lousy to Others who are a threat” (p. 116).

What about our genes? A frequently cited study by researchers Donna R. Miles and

Gregory Carey (1997, p. 207) says that “A meta-analysis was performed on data from 24

genetically informative studies using various personality measures of aggression. There was a

strong overall genetic effect that may account for up to 50% of the variance in aggression.”

Although children have tendencies towards being helpful and expressing kindness, they

are no means blank slates in regard to being self-serving, expressing aggression, and fantasizing

about violence. Quartz and Sejnowski (2002) suggest that aggressive behavior starts early and

depends cultural training to mediate such aggressive responses. Professor of Pediatrics, Dr.

Barbara J. Howard (2011), says that 40 percent of adult violent behavior started before the

individual was 8 years old. Researcher Richard Tremblay says that “the typical two-year old

engages in eight to nine aggressive acts an hour” (Howard, 2014).

Katch (2001) found in her classroom that little boys, when permitted, engage in fantasized

violent play that includes suicide, murder, using their fingers to shoot and kill one another, or

play wild animals that tear people up. What about babies? Hamlin, et al., (2013) found that

infants and children “prefer those that harm dissimilar others.” The authors state: “Across two