Genetic Explanation of Aggression: Aggression is known to be influenced by genetics. Everyone inherits certain genes from their biological parents, these express as specific traits and characteristics. This includes everything from your eye colour, susceptibility to certain diseases, and aggressive tendencies. Some psychologists even believe there is a specific aggressive gene. Genetics are biological, however the explanation does acknowledge the interplay between nature and nurture, a hard and soft approach to determinism. We cannot separate genetics from the environment as it is a crucial part of evolution. Experiments have been conducted on mice whereby they have altered the gene receptor for the neuro-transmitter serotonin. They ‘knocked out’ the gene in the mice. With this a ‘knockout mouse’ was created and put in a cage for 2 weeks to establish its territory. Later when an intruder mouse was introduced, the knockout mice were found to be significantly more aggressive than another control group. This suggests this gene receptor is responsible for the aggression As this was completed in a scientific, lab environment, the results are highly reliable. However there are difficulties generalising from animal experiments to human behaviour. Humans have rational thinking and mice do not. The animal ethics guidelines state that the ends must justify the means. Later research tested rats in the same way, and they found humans don’t have the same gene. Therefore, the experiments are not justified. Aggression rates between MZ and DZ twins who have been reared together are also used for evidence. If genetics was the cause of aggression, we would expect to see a higher concordance between MZ twins than DZ twins, as MZ are genetically identical. Support for this comes from McGuffin and Gottesman, who looked at the concordance rate for aggression and