Is aggression part of our primate nature, wired into our systems because it helps us survive, or do we learn it from such seemingly innocent occupations as watching cartoons and wrestling matches on TV? Can the answer be both? There is evidence in support of both a genetic, evolutionary source for human aggression, and for the role of observational learning in its acquisition.
Aggression and violence are related to one another in that violent actions are aggressive, but not all aggressive actions are violent. In research, aggression is usually defined as either physical (pushing and shoving, for example) or non-physical behaviors (taunting, spreading rumors and insults) that are intended to harm or irritate another person. Violence is physical aggression intended to cause serious physical harm, injury or even death to the other person (Huesmann, 2007).
About 50% of the variability in expression of aggression can be attributed to genetics (Tuvblad and Baker, 2011). We are born with aggression wired into our neural systems, which suggests that there is an evolutionary purpose to aggression. It isn’t hard to see what that purpose might be. We’re aggressive usually to gain something, resources or access to what we need to survive. We don’t always act on our aggressiveness because the other roughly 50% of the expression of aggression is attributable to our environment. That environment includes our interactions with other people, and those other people can be real and physically present, as well as virtual. We learn how to be part of our society and culture through physical interaction with others as well as through observation.
Overall, Americans spend more than six and a half hours per day in front of some kind of screen (television, telephone, computer). In that time, we are exposed to a startling array of violence. According to the National Television Violence Study (2003), almost two-thirds of TV programs contained some violence, which averaged to roughly six violent acts per hour.
Parents and researchers have been concerned about the effects of viewing all this mayhem on children and adults since the advent of television in the 1950s. In the early 1960s, Albert Bandura began a careful examination of the power of observing aggression and violence in children. Children were matched for their initial level of aggression and then assigned to one of three groups. One group observed adult “models” of both genders punch, kick, or hit a Bobo doll (an inflatable plastic doll weighted at the bottom so that if they were knocked over they would come back up for more – don’t judge, I had one). In a second condition the adult models behaved calmly played with tinker-toys and left Bobo alone. Children in the third group did not observe an adult model at all. A week later, the children were given access to Bobo and were watched to see if they imitated the behaviors they had seen earlier. Children, in particular boys, who had watched adults be physically aggressive with Bobo were significantly more aggressive against the doll themselves, copying the behaviors that they’d seen and even inventing new aggressive behavior they had not observed. Children in the other two groups did not show aggression toward any of the toys. Clearly, we learn something about being aggressive by watching others (Bandura, Ross and Ross, 1961).
Bandura went on to formulate what he called Social Learning Theory, which proposed that humans learn not simply through reinforcement of specific behaviors, but also through observation, imitation and modeling (Bandura, 1971).
It turns out that other species of animals also learn aggression through observation, including even mice. Adjei, Qasem, Aaflaq, et al. (2025) examined observation of aggression in mice, focusing on the effects of “social familiarity” on the “witness” mouse. Did being familiar (through co-housing) with the mouse acting aggressively differentially affect the witness to the aggression? Using a mouse model also allowed these researchers to investigate the effects of witnessing aggression on a part of the brain called the amygdala, a part of the emotion and memory circuits in both mice and human brains.
In a specially designed cage that allowed observation but not interaction between mice, witness mice were able to see either familiar or unfamiliar “demonstrator” mice attack an intruder. Male witness mice, but not females, were significantly more aggressive after observing a familiar demonstrator behave aggressively. Neither gender showed any change in aggression after witnessing an unfamiliar demonstrator attack the intruder.
Neurons in the amygdala were activated by watching the familiar demonstrator attack, but not when the demonstrator was unfamiliar. In addition, suppression of these neurons also suppressed aggression, and activating these same neurons chemically while observing an unfamiliar attack promoted aggression. They concluded that who the demonstrator mouse was (familiar vs. unfamiliar) influenced the learning of aggressive behaviors and that this learning was activated by the neurons in the medial amygdala.
Keep in mind that Social Learning Theory predicts we learn both positive and negative behaviors through observation. In 1964, Bandura and Kupers showed that positive behaviors like self-discipline and the motivation to achieve are also learned via observation. Other researchers have found that we might also learn to be altruistic by watching others behave altruistically (Crain, 2000). Perhaps we can countermand some of those lessons those screen hours are teaching by demonstrating to our children through our own actions the way we want them to behave. They are watching us too.
