biological theories Flashcards
what are the biological theories ?
physiological- Lombroso and Sheldon
genetic- jacob xyy theory, adoption studies and twin studies
What is Lombroso theory ?
lombroso compares crime with characteristics such as large jaws, extra fingers, monobrows. he also compared physical characteristics to italian prisoners/soldiers.
males who had 5 characteristics were prisoners and females who had 3 were.
strengths and weaknesses of Lombroso theory ?
strengths
1. he was the first person to study crime scientifically
2. his research prevented future crimes
3. his research saw the importance of studying historical and clinical records of criminality.
weaknesses
1. it lacks accuracy as facial disfiguration isn’t taken in to account
2. features that are seen as criminal are normal to Africans which is classed as racism.
3. research failed to link facial features to criminality
what is Sheldon’s theory ?
he believed that a persons criminal behaviour was linked to physical form.
there are 3 body types- endomorphic, ectomorphic and mesomorphic.
he found many convicts were mesomorphs meaning there were high levels of testosterone and aggression resulting in crime.
strengths and weaknesses of Sheldon theory ?
strengths
1. other studies have replicated his findings
2. glueck and glueck found that 60% offenders were mesomorphs
3. Sheldon saw most serious crimes were committed by mesomorphs
weaknesses
1. labelling
2. people may feel pressure so crime is committted
3. bodies change
what is jacob xyy theory
he stated that crime may be down to chromosomal abnormality
xx- female xy- male
an extra y can appear for males making them hyper mascule, however it is very rare and is 1/1000 new borns.
the extra y is said to make them more violent so crime is likely to get committed.
strengths and weaknesses of Jacob xyy theory ?
strengths
1. links are found between syndrome and property crime
2. adler et al indicated possible aggresive behaviour is determined by genetics
3. significant number of men in prisons have xyy chromsomes
weaknesses
1. rare
2. even if violent offenders have it it doesn’t mean it’s the cause
what is the twin studies theory ?
lange took a study of 30 pairs of twins, 17dz and 13mz. at least 1 of each pair was seen to be committing a crime. 10/13 mz twins were both seen as criminal whereas only 2 dz.
the chance of 1 twin taking part in criminal behaviour whilst other was criminal was 50% in mz and 20% in dz.
strengths and weaknesses of twin studies ?
strengths
1. mz twins are identical so logical behaviour is.
2. ishikawa and raine found a higher concordance rate for identical twins.
weaknesses
1. no way to see if their 100% identical as DNA tests didn’t exist.
2. identical twins are influenced
what is adoption studies theory ?
this is where the behaviour of an adopted child is compared with the effects of adopted and biological parents.
the aim is to sperate the impact of environment and inheritance.
the research shows the adoptees with biological parents who are criminal are more likely to commit property crimes.
study lowa shows adopted individuals who were born as imprisoned, females had a higher rate of criminal convictions as adults.
strengths and weaknesses of adoption studies ?
strenghs
1. it gives support to genetic explanations
2. it exposes to different environments and it’s easy to seperate
3. see the relative importance of nature
weaknesses
1. informartion on biological family isn’t always available.
2. not adopted straight away
3. similair behaviour may be produced to be put in similiar homes.
