Violent behavior is innate in animals, and humans are no exception. Like every other behavior, there are also aspects that are learned. The answer to the question: are humans born violent, or are they raised to learn violence, is yes and yes.
This does not mean that people do not have a choice to learn self control, or that society should in any way accept, or even nurture, destructive behavior.
Nature dictates that to survive animals and plants must exploit other organisms in their environment. There is no “balance in nature”, but an ever changing dynamic that comes to appear stable. There is no separation in the biological reality of what is hereditary and what is learned. Because of epigenetic programming, there are predispositions written into the genetic code that are triggered by immersion into an environment.
For example, a person may not be born with freckles, but at a certain age, triggered by cues of being exposed to natural light, the genes react and produce spots of melanin that come to be known as freckles. This same encoding happens in thousands of instances throughout the life of a human being.
The idea of nature versus nurture is simply a false one, fueled by the human tendency, which is also pre-wired and environmental, to need to comprehend in binary simplicity. This is why humans seek to categorize good and bad, black and white, right or wrong, and so on. No other animal seems to do this to such an overwhelming extent. The result, amusingly, is that many provocative subjects and hence, article titles, ask if something is yes, or no, this or that. In all things, usually, there are aspects of both and shades of gray.
The pre-programmed human body lives in an environment. It is in an environment that learning is added. How humans behave as social creatures is as diverse as allowing slavery, sanctioning murder, exploiting the weak (especially non-humans) and learning to deceive, even as a social grace. Yet humans can also love and display altruism, even to other organisms.
Humans have such sophisticated defense mechanisms that much violent behavior is taken as being “right” and is easily justified in brains that can accommodate discordant, and even contradicting evidence. That whole nations can become Nazis, or machete murders, is in part from the physical endocrine programming, hormones and instincts, but also in cultural conditioning.
It is easy to spot the innate aspects. Proof of this is that one can observe that young males beyond puberty are far more likely to be destructive than others. If environment were the sole cause of such behavior, others in the same environment would behave the same way. More girls, young boys, women and old people would be seen shoplifting, wielding machetes, enamored of guns, video game violence, aggression in sexuality and getting into fights. It may be fun to watch Karl Rove rapping, but it is not natural.
The complexity of cultural sanctions, up-bringing, innate tendencies and every other aspect is quite inter-connected and complex. There is certainly also, some evidence, that human beings, like over-crowded mice in labs, are more stressed, more fragile, more weakened and more driven toward violence when taken out of soothing, natural environments. This should not come as a surprise.
What is a surprise, is the constant willingness for humans to accept destructive choices with the easily accepted concept of “No blame, he/she/we were born that way,” Or just as destructive: “I am depraved on the account that I’m deprived.”
Neither is true. What is true is the simple fact that exploitation results in disaster when the persons, or elements being exploited are overrun, over harvested, over oppressed, or over abused. It is true of people hurting people, and people hurting planets. So long as people are taught to hurt and exploit by example they likely will. When they learn it is not wise, they benefit, as does the culture.
Humans are in an abusive domestic relationship with their source of life and making a living: the regenerative, but finite sustenance of nature. Violence is a symptom of this alienation. Wars, toxins, pollution, over-harvest of other species, exploitation of human and non human resources, are all due to something which humans have the power to affect, namely their thinking, and their behavior. Since the entire planet is now in peril from human tendency to stay in denial, hurt one another, refuse empowerment, exploit beyond sustainable limits and fight to the death over resources, it is time for the human species to grow up.
People, who think rationally and inquire skeptically, come to know the human being can improve, innovate and empower their belonging to a global community. People do not need to continually scapegoat either nature or nurture, although the non-thinking reactive choice is to deflect all responsibility.
It is time for human beings to accept they can and do have power, because of what gifts they are born with, and what they learn. People have the mental capacity to think logically, act responsibly, feel compassionately and behave civilly. Do it.