Warrior Gene (MAOA)

What is the Warrior Gene (MAOA)

-A gene and the enzyme the gene produces

-Breaks down NT’s after use to balance brain chemistry

-Low MAOA= Less enzymes= More chemicals in brain leading to poor regulation of NT’s

Why MAOA affects behaviour

If NT’s aren’t broken down:

-Brain becomes overstimulated

-Weaker emotional control

-Increased aggression

Why its called the Warrior Gene

-Low MAOA activity linked to aggressive + impulsive behaviour

-Could increase risk taking/violent responses

What was the theory of Caspi et al (2002)

Showed that the effect of childhood mistreatment on later antisocial behaviour depended on MAOA gene variation

Men with low MAOA activity that were mistreated as kids are more likely to develop:

-Violent criminal behaviour -Antisocial personality traits

-Men with high MAOA activity less likely to develop

MAOA and Dopamine

High dopamine can cause

-Risk taking

-Crime for excitement

-Increased chances of doing risky crimes

MAOA and Serotonin

Low serotonin linked to aggression + impulsivity

-Low MAOA linked to serotonin functioning= reduces emotional control

MAOA and Norepinephrine (NPP)

High levels cause:

-Aggressive responses

-Overreaction to threats

Is MAOA linked to NPP

-MAOA gene controls production of an enzyme that breaks down NPP

-High MAOA activity= NPP broken down properly

-Low MAOA activity= NPP builds up in brain

-Low MAOA levels= NPP to not be regulated properly= Increased stress levels

Warrior Gene evaluation

Advantages:

-Biological evidence= research shows low MAOA activity affects brain chemistry/linked to increased aggression

-Explains individual differences= low MAOA activity causes people to have poor emotional/impulse control

Disadvantages:

-Deterministic- suggests behaviour is only caused by genetics

-Can’t explain all crime= doesn’t explain planned/non violent crime

-Need environmental triggers= abuse causes increased chance of violence in low MAOA activity men