Genes, environment, brain and behaviour

Question 1

Why is it so difficult to establish a
biochemical chain of causation between
specific genes and complex human
behaviors?

Answer 1

Must establish which genes are involved and how
they affect the biochemistry
of brain cells in ways that influence behavior.
Many genes with small size effects each
Epistasis: gene interactions
can affect phenotypes
Epigenetics: changes to genes expression which can mediate the effect of the
environment
Genes X Environment interaction

Question 2

Why is it so difficult to find a
causal relationship to
Neuroscience findings applied
to human behavior?

Answer 2

Different timescales in operation
Different levels of enquiry
involved
A variety of social factors, difficult
to establish and to control, affect
the scientific process

Question 3

Gene vs environment interaction examples

Answer 3

MAOA (gene for removing excess dopamine and serotonin) & aggression
But… e.g. Maori people often experience maltrearment too