The popular and professional acceptance of strong connections between types of violence is beginning to be used to justify social work interventions and to influence legal decision making, and so requires greater scrutiny. It has been suggested that acts of violence against human and nonhuman animals share commonalities, and that animal abuse is a sentinel for current or future violence toward people.

After reviewing the evidence, it is reasonable to suggest that there is not one singular cause of serial killing, rather a variety of social, biological and cognitive factors and that can cause someone to be susceptible or expedite the process of becoming a serial killer. Lastly, personality disorders are explored in relation to social, biological and cognitive psychology and how they link to serial killing.

Cognitive psychology explores how brain dysfunctions can lead to serial murder, with emphasis on head injury causing frontal lobe damage. Biological psychology explores the nature side of the debate, with emphasis on chromosomal abnormalities, a biological predisposition for crime and other biological functions. Social psychology explores the nurture side of the ‘nature vs nurture’ debate, with emphasis on childhood trauma, re-enactment and self-evaluation. Definitional problems with defining serial murder has led to confusion when classifying murder and therefore its causes. Serial murderer is classified as the murder of 3 or more victims by the same offender, over multiple locations with the presence of a cooling off period (Ressler et al, 1988). A plethora of literature and various case studies of incarcerated serial killers have been used to support or debunk the theories explored. Therefore, the aim of this thesis is to look into potential causes of serial killing, with emphasis on social, biological and cognitive psychology. Although serial killing was only defined in 1988, there is still more research to be conducted into the causes of this phenomena.

Percentage of serial killers by gender