Biological explainations

• Lombroso identified physical features that linked to lower development levels that predisposed you to crime.
• Lombroso worked off of Darwin's theory, believing that criminals were a step back in evolution.
• Lombroso examined 4000 criminals and 400 dead criminals. He found features like: sloping brow, pronounced jaw, high cheekbones, large ears and extra nipples, toes and fingers.
• Despite Lombroso's findings being unreliable, he made a foundation that people were genetically predisposed to crime. Kaplan devised the self-derogation theory. The theory was founded on people experiencing anti-social interactions due to their appearance develop a frustration to society and therefore are more likely to commit a crime.
• Goring replicated Lombroso's study with a control over 100 years later and found no significant differences between the 2 groups in appearance of atavistic form.
• Genetical explanations to offending behaviour

  Twin studies, family studies, adoption studies
• Christiansen in 1977 carried out a twin study in Denmark about criminal behaviour. There were 3,500 pairs in his sample. He found that MZ had higher concordance rates, and males have higher concordance rates in both MZ and DZ. However the rates weren't 100%, demonstrating that environmental factors had a role to play.
• Christiansen's study had good population validity however twin studies are seen as problematic due to the fact the don't rule out environmental influences, and that criminal behaviour can be learnt from social learning. Despite this, adoption studies are a much better measure to genetic predispositions.
• Brunner carried out a family study on a Dutch family who had high crime rates (one of which is attempted rape). This was due to deficiency in their MAOA gene.
• The MAOA gene is a enzyme responsible for the metabolism of serotonin, a neurotransmitter linked to aggression. A deficiency in this gene is called Brunner syndrome. It is carried by women but presents itself on the male X chromosome.
• Crowe carried out an adoption study with 2 groups: one with biological mothers with a criminal record and one without (control).
• Crowe's results found that 50% of adoptees with biologically criminal mothers had a criminal record by 18, compared to the control group who had 5%.
• The biological approach to explanations of offending behaviour supports the nature perspective. However, it's ignorance to environmental factors and parenting can eb viewed as reductionist.
• Brunner's research is idiographic and has a case study nature which means it is not generalisable.
• There are two key neurotransmitters involved with offending behaviour. Dopamine links to pleasure and reward, making crime more replicable, linking to addiction and drug use crimes. Serotonin is associated with mood and impulsiveness as well as aggression.
• Buitelaar carried outa study were he gave children in Juvenile Prison dopamine antagonists ( lower levels). This resulted in a decrease of aggressive behaviour.
• An evaluation of Buitelaar's study is that not all crimes are aggressive in nature, meaning it cannot be applied to all crimes. Also, the study is correlational, meaning it cannot be used to prove causation.
• The amygdala is responsible for emotion regulation and aggression. Research into psychopaths found that dysfunction can lead to issues with processing emotion and empathy, meaning criminals can have no remorse.
• Potegal stimulated hamsters amygdala and found that it lead to more aggressive behaviour. However, animal studies lack generalisability but they are helpful to prove causation without violating ethical codes.
• The frontal lobe is part of the neocortex and is responsible for higher functions like sociality and planning. There are links between lobe dysfunction and violent crime. However, this is reductionist to the approach as violence isn't always the route of crime.
• Freed studies frontal lobe damage and anti-social behaviour. He found that it lead to emotional instability and the failure to consider consequences as there is no adaption to external ques. However, not all crimes are antisocial in nature.
• Raine et al is a key study which identified regions of the brain specific to murder and manslaughter. The sample was 41 males and 2 females who didn't plead non guilty by insanity. They were PET scanned, involving a radioactive injection.
• Raine found reduced activity in areas such as the corpus collosum, prefrontal cortex and the limbic system. The prefrontal cortex is linked to social cognition. The thalamus in the limbic system is responsible for safety and survival.
• Overall, Raine's study suggests offenders brains are slowed which cause them to react inappropriately with the inability to see consequences.
• Raine study was correlation. This means it lacks causation explanation and begs the question to whether the dysfunction was caused by environmental factors or if the crime led to the change.
• Neurochemical explanations have be criticised for being too simplistic. The links between imbalance often centre around violent crime which doesn't explain all types of crime.
• The biological approach is deterministic which causes implications to responsibility and the justice system.
• Charles Whitman murdered 15 people and shot 45 in 1966. When a post mortem was carried out it was found he had a large tumour pressing on his amygdala. This questions responsibility.