A03: Genetic & Neural - Biological explanations

• Evaluation of Genetic & Neural


  Genetic Explanations

  -Assuming equal env

  +Support for diathesis-stress model of offending

  -Nature vs Nurture

  
  

  Neural Explanations

  +Support for link between crime & frontal lobe

  -Link between neural differences & APD is complex

  -Biological Determinism
• -ve: Assuming equal environments - A03 G&N

  Often assumed that environmental factors are the same for MZ & DZ twins because they experience similar environments

  • But because MZ twins look identical, people (eps parents) tend to treat them more similarly which in turn affects their behaviour (identity issues too)

  Therefore higher concordance rates for MZs may be because they are treated more similarly than DZs suggesting conclusions lack validity.
• +ve: Support for link between crime & frontal lobe

  Kandel & Freed (1989) researched people with frontal lobe damage, including the prefrontal cortex.

  • They found evidence of impulsive behaviour, emotional instability & inability to learn from mistakes.

  This supports the idea that structural abnormalities in the brain are a casual factor in offending behaviour.
• -ve: Link between neural differences & APD is complex

  Farrington et al (1981) studied adult males with high APD scores. They were raised by a convicted parent & physically neglected.

  • These early experiences may have caused APD & associated neural differences e.g reduced activity in the frontal lobe due to trauma

  This suggests that the relationship between neural differences, APD and offending is complex and there may be intervening variables
• +ve: Diathesis-stress model:A03 G&N PART 1


  Support: DS model of crime/offending by Mednick et al (1984) studied 13,000 Danish adoptees have least 1 court conviction

  • Conviction rates 13.5% (biological/adoptive parents had no convictions), 20% (1 bio parent), 24.5% (both adop & bio parents).
  • Gradual systematic increase in criminal behaviour with increasing genetic risk (presence of criminal parents) suggest genetic predisposition plays role & interacts with env factors to influence behaviour.
• +ve: Diathesis-stress model:A03 G&N PART 2

  • But, difference in rates show influence env factors have on behaviour so must consider both bio & env factors when understanding criminal behaviour.

  Suggest both genetic inheritance & env influence criminality - supporting diathesis-stress model of crime
• -ve: Methodological Issues:A03 G&N PART 1

  Method issues in twin & adoption studies of criminality.

  • Twin studies: Langes work lack control coz relied solely on appearance to determine zygosity (MZ or DZ) method prone to errors compared to contemporary DNA testing. Raises concerns about validity of findings. Also twin studies have limited sample size; difficult to draw generalisable conclusions about wider pop.
  • Adoption studies: Mednick et al. (1984) focus on petty offenses like burglary, could overlook influence of genetic & env factors on more serious crimes.
• -ve: Methodological Issues:A03 G&N PART 2

  Limitations show need for caution when interpreting findings from early twin studies on criminality.

  • Limits generalizability of adoption studies findings to the broader spectrum of criminal behaviour.

  More rigorous methods & larger samples key ensure accuracy & generalisability of future research in this domain.
• -ve: Biologically Reductionist and Deterministic: A03 G&N

  1. Biological reductionist

  Criminality is complex - genetics as an explanation alone is too simplistic 

  1. Biologically deterministic 

  A ‘criminal gene’ is problematic for the legal system - raises questions over blame & free will.
• -ve: Adoption Studies: A03 G&N:PART 1

  Adoption studies valuable tool for disentangling relative influences of nature & nurture, they not without limitations:

  Shared Env before Adoption:

  • Reality of late adoption: Assumption that adopted children are environmentally distinct from their bio parents often challenged by reality of late adoption. Many kids spend significant portion of early development with their bio families, potentially shaping their behaviour through shared experiences & influences. This confounds attempt to isolate unique env impact of adoptive parents.
• -ve: Adoption Studies: A03 G&N: PART 2

  Ongoing Contact with Biological Parents:

  • Even after adoption, some individuals maintain regular contact with their biological families. This continued exposure to the biological parents' environment further complicates the isolation of the adoptive environment's influence on behaviour, making it difficult to attribute specific traits solely to nurture within the adoptive family.
  • continued exposure to the biological parents' env further complicates isolation of the adoptive env's influence
• -ve: Adoption Studies: A03 G&N: PART 3

  These limitations necessitate cautious interpretation of results from adoption studies. Researchers must acknowledge the potential influence of shared pre-adoption experiences and ongoing contact with biological families. Additionally, they should strive for designs that encompass a wider range of criminal behaviours to ensure their findings are generalizable.