Is violence an evolutionary trait?
Men are more likely than women to perpetrate nearly all types of interpersonal violence and are the most common victims of interpersonal violence. Research has largely focused on the role of gender norms and masculine values in promoting male violence. It has been argued that the prevalence and pattern of male violence is a result of the social norms which cause men to value hierarchy, power, respect, and emotional suppression. These factors definitely play a part, but there may be a scientific explanation to explain the patterns of male violence we see.
In Death from a Distance and the Birth of a Humane Universe, Bingham and Souza present an explanation of male violence based on the difference between the roles of males and females in mammalian reproduction. For males, mating with multiple females increases their potential reproductive output – a man can get multiple women pregnant. However, for females, mating with multiple males has little to no effect on their potential reproductive output – a woman cannot be a little pregnant.
If an organism’s purpose is to have as many offspring as it can, as Bingham and Souza argue it is, then it is advantageous for males to have multiple mates. These males, therefore, will compete for females to mate with. This is not a new idea, but one that isn’t always considered in the search for the origins of male violence.
Based on this idea of male-male competition, it is logical to assume that violence between males should be the most prominent form of violence. That is exactly what we see. Males are nearly ten times more likely to commit homicides and are 2 to 3 times more likely to be victims of homicide, compared to females.
Furthermore, we can assume males who have the most competitors for mating opportunities should be involved in violent competitive interactions more often. Again, this is exactly what we see. Unemployed, unmarried, young men are the most common offenders and victims of homicide. Young males between the ages of 20-24 are almost five times more likely to commit homicides than older men aged 50-54. Moreover, unemployed men in their peak reproductive years (aged 25-44) are around five times more likely to commit homicides than employed males of the same age.
Of course, these statistics are not a result of evolutionary processes alone. Humans exist within large, complex communities, and the socially pressures ideas and cultural values within these groups will impact our behaviour. However, scientists have argued that this behaviour initially evolved in response to sexual selection by females, and is socially facilitated by the presence of other men in pursuit of the same goals.
Further evidence for this theory comes from our closest living relatives – the great apes. It has been shown that the most severe forms of violence between males in these species tend to be linked to sexual access and reproductive success. Furthermore, females seem to be attracted to these males who successfully compete, resulting in male violence being actively selected for in both sexes.
You may find yourself thinking that humans have risen above these basic motivators for sexual reproduction. Yes, we are more complex than other mammals, and we live within expanded social contexts which influence our behaviour in very different ways to apes. But, our genetic information has been shaped in the same way as other mammals over millions of years. As a result, our behaviours are still influenced by these same fundamental needs. This may help us to understand the cause of male violence in our species, and perhaps give us some clues on how to prevent it.