Agression – Are We Born Agressive Or Is It Learned?

  • Category: Psychology
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  • Grade: 92
Are we born aggressive or do we lean to be aggressive?

There is much debate among psychologists as to whether we are born aggressive or learn to become so, with an abundance of evidence supporting both ideas. In this essay I intend to present and evaluate both sides of this argument in order to gain a clear picture of these two points of view.

The biological side of the argument states that the difference between aggressive and non-aggressive individuals is due to differences in the genes.
Throughout the centuries, ideas about the biological influence on aggression have changed and developed. For example, in the 19th century, It was thought that body types played the main role. This fits the modern stereotypes of 'thugs' i.e., well built, deep set eyes etc"¦.In the 20th century and into this one, it is thought that there are three main factors influencing an individual to be aggressive; neuroanatomical factors (brain), neurochemical factors (chemical imbalances, testosterone levels etc"¦), and genetics.

Firstly, The important areas in the brain for affecting aggressive behaviour are the pre-frontal cortex, the hypothalamus and the amygdala. In 1976, Moyer conducted studies that showed that electrical stimulation and lesions in these areas could increase or decrease aggression. He also found that differences between individuals in any of these areas (caused by trauma, disease etc"¦) affected their aggressive tendency. Whether noticeable changes occur as a result of these differences depends on situational factors. Studies done on animals have shown that the same level of stimulation triggering aggression against a small opponent may not trigger aggression against a larger one.

There are two main chemicals in the body that affect aggression; Seratonin and Testosterone.

Seratonin is a neurotransmitter involved in inhibiting impulsive responses to frustration.
Knoblich and King, in 1992 found that a decrease in the level of seratonin in the body increased the risk of aggressive behaviour. In their studies they used animals and saw a depletion of seratonin, for example in their diet, would cause aggressive behaviour.
They also found that children with naturally low levels of the chemical were more likely to be aggressive.
In 1983, Linnolia et al studied men imprisoned for various reasons. They found that men who had been imprisoned for impulsive violent crimes had lower levels of seratonin than those men imprisoned for non-impulsive violent crimes.

It has been suggested that high levels of testosterone in both the womb and through early childhood cause the development of an aggressive neurophysiology. It has also been shown that increased levels of testosterone at any moment increases the likelihood of aggressive behaviour at that point.
In 1981, Reinisch showed that if the daughters of women treated with a hormone similar to testosterone during pregnancy grew up to be more aggressive than girls in a controlled group who had not been exposed to the drug.
O Lweus et al (1988) found that an increased level of testosterone in adolescent boys caused them to behave more aggressively when provoked..

Genetic evidence for a biological basis to aggression is mostly based on twin studies and adopted children.
In 1988, Tellegan et al studied twins who had been raised apart from birth showed higher correlation between identical than fraternal twins. However, Professor Plomin conducted a similar study and found a 40% similarity and 60% dissimilarity between twins. He concluded that violence was not genetically linked in any great degree.
Longitudinal studies by Mendick et al in 1987of boys adopted at birth showed a significant correlation between natural fathers and their adopted sons being convicted of violent crime. 14000 adopted children were involved in a similar Danish study that provided a contradicting conclusion. The children were compared to their biological parents and no link was found for aggression but there were strong links for theft.
The psychologist Lorenz believed that aggression is biologically innate in humans on both an individual and group level, but modern society has removed certain instincts and the development of guns (at a micro level) and weaponry (macro) has altered the implications of our aggressive tendencies.

The exact origin of a biological cause of aggression is secondary to the way that certain dispositions influence the way that the environment moulds a child's ideas and schemas to produce different responses to provoking, external stimuli.

The main theory backing up the 'social' view of aggression is the 'Social Learning Theory'. As the name suggests, this theory is based on the idea that we learn to be aggressive. It basically says that we gain reinforcement by watching other people behaving aggressively. This is known as 'indirect reinforcement'. If the 'observed' is seen to be praised for their behaviour, it acts as a positive reinforcer and encourages us to behave in the same way. Our view of the 'observed' does have some effect on the behaviour we show. If we can relate to, or have a high opinion of them, we are more likely to show the same behaviour.

The main psychologist in the development of this theory is Bandura. In 1973, he conducted an experiment with an inflatable clown doll called Bobo. The experiment involved two groups of school children, one who watched another child playing aggressively with Bobo i.e./ hitting and throwing it and the other group watching a child paying non aggressively with it. He then put the children into a room with a mixture of aggressive and non-aggressive toys i.e.: guns and balls and also Bobo the clown. He found that the children who had witnessed the aggressive behaviour were more likely to choose the aggressive toys and play aggressively than the children witnessing the non-aggressive behaviour. He also found that if the children related to the person displaying either behaviour, they were more likely to copy it themselves.

There are however, some criticisms of this experiment. The main one being that the children may simply be displaying 'demand characteristics'. They may have been given cues to act in a certain way. Secondly, in real life, aggressive behaviour isn't often praised or rewarded - Banduras work is said to be over simplified.
He did however also find that most aggressive children in 'slum' districts usually learn their aggressive behaviour from their peers in the streets. In middle class families, he found that the parents of aggressive boys encouraged their sons to be aggressive towards other people. Non-aggressive boys came from families in which the parents encouraged their sons to be firm in defending their principles, but discouraged physical aggression as a means of settling disputes. He concluded again that children draw on their parent's aggressive tendencies as a model for their own behaviour. Similarly, Hoffman found that mothers who used verbal and physical aggression as discipline frequently produced children who used similar behaviour towards their peers.

One theory that seeks to combine the two arguments, while emphasising the importance of social factors is the 'Frustration - Aggression theory. Basically this theory suggests that frustration always causes aggression, and aggression is always caused by frustration. It is when we are prevented from doing something we want to that we become frustrated. This frustration leads us to behave aggressively. The phenomenon of Road Rage supports this theory.
Evaluation of this theory however says that this is not the case. We often feel frustrated but we do not always become aggressive as a result. It also asks the question of whether our aggression is always caused by frustration.
The psychologist Berkowitz does not rule out frustration but suggests that other social factors may be involved and while frustration may produce feelings of aggression inside us, we need a cue, an external/environmental stimulus in order for us to show this behaviour.
He conducted a study with another psychologist - Green in 1981 in which a group of adults were made to feel frustrated by being asked to complete a task that was infact impossible to finish. He then asked them to take part in a teacher/learner role-play in which they, as the teacher, could administer an electric shock if a wrong answer was given in response to a question they asked. The teacher could choose how strong the shock could be. He found that those people who had been made to feel frustrated were more likely to administer a bigger shock than those who hadn't.
Other environmental factors such as overcrowding and noise also act not only as cues but also as causes of aggression.
The 'excitation-transfer' theory links in with the frustration-aggression theory. It states that those people involved in physical activity were more likely to behave aggressively because they transfer the biological arousal from their activity into aggression.

The development of every human behavioural trait is the result of the interaction between genetic and environmental factors. It seems that the explanation of the causes of aggressive behaviour lie not only in an individuals life long experiences, which will vary widely from person to person, but also in a genetic contribution.
While there is evidence to suggest that there are many biological factors that increase the likelihood of and individual behaving aggressively, it would seem that an environmental stimulus/cue is needed for this behaviour to be shown.
It would therefore be sensible to suggest that a persons genetic makeup provides the potentialities for aggression, but the environment to which we are exposed and the experiences we have throughout our lives, determine to what extent and to what degree they will develop.


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