Essay // Aggression: The Biological & Psychological Explanations


As humans, our ends have proven to shape our behaviour which can unfortunately not always be rational. One form of irrational behaviour is aggression, and in the realm of psychology its explanation has long been an issue among psychologists. We will try and explore the explanation provided by biological psychologists who believe aggression is an evolutionary inheritance, while behaviourally inclined psychologists believe in the Social Learning Theory – which suggests all aggressive behaviour is learned through interaction in the social world.

The Biological Argument

Biologically inclined psychologists relate the source of aggression to the brain which they assume to be a machine that controls all behaviour. The concept of free will – as with most other psychological approaches, is discarded – since the brain is believed to be reflecting factors such as: tendencies inherited through genetics, the way parts of the brain are functioning, and the chemical influence of substances – such as alcohol, drugs and/or toxins.

According to Lorenz (1966), aggression in humans is legitimately comparable to other non-human species and is believed to be the result of evolutionary development – he defined aggression as “… the fighting instinct in beast and man which is distinct against members of the same species.” (Gross, 2006 p420).

Another biological explanation believes that certain behaviours are linked to the functioning of particular parts of the brain. This claim was supported by a patient known as “Dawn” who started acting erratically – even worryingly macabre in thought – when her cerebral cortex (the part of the brain responsible for planning, reasoning and ‘rational’ behaviour) would start to shut down as a result of her blood-glucose level drop due to diabetes.

The third biological reason for aggression is related to chemical influences (such as alcohol, drugs, Serotonin) on the brain which can lead to aggression – Putnam et al (2000) observed how levels of serotonin are considerable low in violent criminals. Although strong claims and evidence give Biologically inclined psychologists credibility (with solid laboratory experiments), the deterministic and reductionist views it promotes raise arguable issues; as important factors such as learning and cultural influence are discarded – along with free will, which defies the essence of human freedom, an explanation many find questionable.

The Psychological (Social/Learning) Argument

Psychological explanations based on the Social Learning Theory also hold strong evidence providing plausible explanations while discarding the explanations of Biologically inclined scientists. Researchers advocating psychological explanations (such as Bandura) support the nurture side of the “nature VS nurture” debate on human behaviour; and believe that a person from birth is influenced by their surrounding and upbringing – which is explanatory in the Social Learning Theory. The theory suggests that aggression is learnt in 2 ways, by direct experience which is based on operant conditioning (reinforcement) or by vicarious experience which is based on observational learning.

To support his theory, Bandura (1965) used the ‘Bobo Doll Study’ where male and female participants aged 3 to 5 years old with half of the group exposed to models behaving violently towards the life-sized Bobo doll whilst the other half were exposed to models with no aggression. This lead to the children exposed to the aggressive model reproducing most of the physical and verbal aggression whereas the children unexposed showed virtually no aggression.

Another explanation to aggression is “de-individualisation” where Dr Philip Zimbardo’s (1969) prison experiment proved how constraint on behaviour is weakened when a person loses their sense of individuality – where the group of participants [in the experiment] who were allocated the Guard-role had started acting in an extremely vile and degrading manner towards the participants allocated to “prisoners” when the former had been wearing sunglasses (which heightened their anonymity thus lowering their sense of identity). Such incidents happens in situations when (for e.g.) in crowds, or in a uniform where one can feel less likely to be held responsible for aggressive behaviour.


However, both explanations suffer from Ecological Validity – and may not be able to fully predict or provide sufficient explanations to real world situations due to the controlled conditions of the experiments used to support the assumptions. Furthermore, discarding biological factors also seem to have a negative impact on its conclusions as it is known that the physical state of the brain is vital to fully assess behaviour based on an individual deemed “healthy & fit”.


The explanations on both sides provide strong arguments in explaining the reasons behind aggression but fail to provide solid claims over the causes and preventative measures. However, while both fail to prove their efficiency on claims, their contributions to psychological research seem equally important and plausible. The Social Learning Theory holds strong explanation for aggression (imitation) while the biological approach also has strong evidence – in Bard (1940) aggression in cats was linked to the removal of the amygdala.



Gross. R (2005) Psychology: the science of and behaviour. Pp 420-421 London, Hodder and Stoughton Educational

Boakes. R (1984) From Darwin to behaviourism: Psychology and the minds of animals. Cambridge University Press

Cohen D. (1979) J.B Watson: The Founder of Behaviourism. London, Boston and Henley


22.04.2014 | Danny J. D’Purb |


While the aim of the community at has  been & will always be to focus on a modern & progressive culture, human progress, scientific research, philosophical advancement & a future in harmony with our natural environment; the tireless efforts in researching & providing our valued audience the latest & finest information in various fields unfortunately takes its toll on our very human admins, who along with the time sacrificed & the pleasure of contributing in advancing our world through sensitive discussions & progressive ideas, have to deal with the stresses that test even the toughest of minds. Your valued support would ensure our work remains at its standards and remind our admins that their efforts are appreciated while also allowing you to take pride in our journey towards an enlightened human civilization. Your support would benefit a cause that focuses on mankind, current & future generations.

Thank you once again for your time.

Please feel free to support us by considering a donation.


The Team @

Donate Button with Credit Cards

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s