How Does Human Develop Aggression?

How Does Human Develop Aggression?

Social psychology defined aggression as an anti-social behaviour that intended to harm an individual in any form, be it physically or mentally (Marshall & Welk, 2008). It can be differed into two main type, hostile aggression (an impulsive behaviour driven by emotion with the aim of hurting someone) and instrumental aggression (a proactive behaviour with the aim of fulfilling an outcome rather than hurting people). Besides that, the study of human aggression can be quite complicated as it involves a wide range of fields, such as, psychology, physiology, neurology and ethology. Moreover, with all the news about school shootings, bullying, parental abuse, understanding the development of human aggression is necessary. Scientists believed that our behaviour is determined by both nature and nurture. Therefore, the development of human aggression will be discussed below from our ‘own self’ to the ‘outside world’. ‘Own-self’ as in how we Homo Sapiens eventually caught up with aggression ethologically and how our bodies control aggression physiologically, whereas from the ‘outside world’, we will see how environment influence human behaviour.  

To begin with, it should be emphasized that behaving aggressively is not only because of anger but can also be for survival. From the study of ethology, animals usually behave aggressively when they are in a condition where their lives are in danger or in a competition for their necessities such as food and space. This can be interpreted that aggression is one of our mental mechanism. When emotions such as fear struck, we may behave aggressively. For an example, chimpanzees are seen fighting with another animal to protect their offspring because of the fear of losing their loved ones. Chimpanzees are one of the human’s closest living relatives and both share the same ancestor. Therefore, the evolution of chimpanzees’ behaviour is similar with humans’ (Zinner & Wheeler, 2013). Behaving aggressively is the method of adapting to this competitive world. Though, certainly it is not the only way. As accurate as Darwin’s theory of natural selection that says those who can adapt will survive and those who cannot will be long gone.

To view aggression as an innate behaviour, it can also be explained from the biological point of view, too. Archer (2009) explained that the brain mechanism that controls human aggression is very complex compare to other animals. He then elaborated that the sympathetic nervous system located in human brain and spinal cord is the main mechanism that will prepare us to be ready to respond to situations. To reinforce this point, in Panksepp’s 1998 study (as cited in Archer, 2009) he had successfully found the neural circuits in our brain that control aggression. The way our brains react automatically towards aggression had strongly pinpointed that human aggression is being developed naturally.

On the other hand, in the latest study of the General Aggression Model (GAM) (Allen, Anderson, & Bushman, 2018), it had delineated that some inborn medical condition such as attention deficit hyperactivity disorder (ADHD) will increase the probability of human developing aggression. Besides that, recent studies had just explained that maternal environment may be one of the factors that causes the insufficiency in behaving socially normal (Richard E Tremblay & Szyf, 2010). This means that the lifestyle of women during pregnancy, from what they eat to their mental state, it could have epigenetic effect (the changes of gene expression due to environmental influence) on the baby’s brain development. The most common maternal lifestyle that will cause negative effect on the child is smoking and drinking during pregnancy.

Therefore, with the knowledge of epigenetic effect, we know that genetic expression has correlation with the perinatal environment, which then affect our brain structure and behaviour. In the iconic twin studies (Ferguson et al., 2008; Waltes, Chiocchetti, & Freitag, 2016), it was explained that even though twins are born with significantly similar gene and usually share the same environment (e.g. education, parental guidance), the twins will not grow up to be exactly the same. They often have different personality, different hobby or have different ability. This is due to their non-shared environment (e.g. role in the family: eldest child, middle child, youngest child or different group of friends). Hence, it was concluded that the non-shared environment cause changes of epigenetic patterns, which also meant that behaviour can be learned in life.

In early childhood, families especially parents play an important role in moulding a child’s personality. The reaction of parents towards a child’s raging behaviour will result with the level of aggressiveness. It increases when the behaviour was rewarded, decreases when it was punished (Van Goozen, 2005). For an instance, when the child was crying hysterically for a desirable object and was then given directly without telling he or she the correct way to ask for it, the child may ‘learned’ that it was the only way for that. Children absorb knowledge the fastest during their early childhood, therefore, the environment they grew up in very much influence their behaviour (Richard Ernest Tremblay & Nagin, 2005).