There are several ways in which genetic factors in aggression have been investigated. In the 1960s and 70s a popular theory was that males who have inherited an extra Y chromosome are more 'male' and therefore, more aggressive; however, this hypothesis as been shown to be incorrect. Nevertheless, animal breeding studies consistently show that it is possible to select for aggressiveness and twin and adoption studies in humans suggest that genes influence aggressive behaviour; more recently, psychologists and biologists have developed a better understanding of how genes can influence behaviour by using new technology to investigate the genetic mechanisms that lead to increased aggressiveness.  

Resource of the Week: Audio Interview With Schizophrenia Researcher Tim Crow This week's resource is an audio interview with Professor Tim Crow where he discusses the genetic origins of schizophrenia. It's set to funky music so you can dance along!

New research carried out by sociologists has added to wealth of evidence that nature and nurture cannot be treated as separate factors when explaining human behaviour: human behaviour is the result of interactions between genes and the environment. Whether genes are expressed depends on environmental factors and genes themselves can change the environment.

Nature v Nurture: Homosexuality due to genes and environment The world's largest twin study indicates that homosexuality is due to both nature (genes) and nurture (the environment); however environmental factors that are specific to the individual (e.g., pre-natal exposure to hormones) are more important than shared environmental factors (e.g., parenting).