When was the last time you insulted someone? How many times have you been cut off by an aggressive driver? Ever been slapped? Aggression can rear its head in many of our daily interactions, even when we’re unaware of it. According to psychologists, an act of aggression is intended to hurt another person, whether it’s physical, mental, or verbal. Psychologists distinguish between “instrumental” aggression, which is harm inflicted in order to achieve a certain end, like personal gain or self-defence; and “emotional” aggression, which is harm inflicted for its own sake.
The biological elements of aggression are well studied but controversial. It’s a question of which bodily factors—be it neurotransmitters, hormones, or brain patterns—get us going. As it turns out, there is a strong association between androgens like testosterone, and physical violence. In seasonally breeding animals, testosterone levels change over the year, and levels of aggression follow in tow. When male dogs are neutered, their androgen levels drop, along with inter-male aggressive behaviour.
In humans, higher testosterone levels have been linked with hostility and antisocial behaviour. What’s more, testosterone even seems to play a role in “symbolic” aggression, like sports and competitive situations. Male fans watching a sporting event will have higher testosterone levels if their team wins, while fans of the losing team will see their levels decrease. Even if you win a game of chess, you will most likely demonstrate an increase in testosterone. The trouble is, we don’t know whether it’s the androgens causing aggression or if it’s the other way around.
Another biological factor associated with aggression is the neurotransmitter serotonin. Research suggests that higher serotonin activity in the brain is associated with reduced aggression. This implies that serotonin might inhibit aggressive behaviour. Diminished serotonin levels are seen in people who become violent, for example, after alcohol consumption, U.S. marines who are expelled for being too violent, and even children who torture animals. Specific abnormalities in brain activity have also been found in aggressive people, for example, seizures in the temporal lobes might precipitate violent behaviour.
But the biological study of aggression is a sticky situation at best. Aggression seems to be regulated by a large number of different systems and stems from a number of different sources. Despite an attraction to biological explanations, we can’t forget that social factors also influence aggressive behaviour in crucial ways.
In a classic study of learning and aggression by Albert Bandura, children observed an adult playing with a “Bobo doll,” a large inflatable toy. In one condition, the adult acted aggressively toward the doll, tossing it, kicking it, hitting it with a hammer, and shouting. The children were then left alone with the toys while researchers observed and rated their behaviour. The results showed that children tended to imitate the adult, and played more aggressively when the adult did so. Surprisingly, the children even made “creative embellishments” in their doll torture, for example, by pounding the Bobo doll with another baby doll.
Learning is an important component of aggressive behaviour and has serious implications for parents raising children. For example, since kids tend to imitate their adult role models, does spanking cause increased aggressive behaviour in the child? Research suggests that while punishment might reduce misbehaviour at home, it can actually increase a child’s violent behaviour outside the house. Another issue which has captured the hearts of mothers everywhere is the association between violent music, movies, television shows, and videogames and aggressive behaviour. While it’s difficult to conclude whether violent TV actually causes aggression, a number of studies suggest that watching violent programming can predict aggressive behaviour even later in life.
Another area of study looks at the kinds of situations and environmental conditions that make us violent. In general, we can get aggressive when we’re interrupted from achieving a goal—in other words, when we’re frustrated—or when we consume too much alcohol. Even the environment can influence aggressive acts, especially those factors that increase discomfort. More homicides are reported during uncomfortably hot summers than milder ones. Studies like these can teach us a lesson or two about how to handle conflict. So next time you’re in an argument, lay off the booze, don’t interrupt, and turn up the AC. There are some things to which we can all agree.
