A strength of biological approach?

-Research that increases internal vlaidity -Phenias Gage, metal rod that was in his left eye and into the ventromedial area of pre-frontal cortext, the area that controls impluse and emotional response -Found that there was a behaviour change with Gage, he went from being very polite and calm to very erratic and rude, behaviour didn't reflect his past self -Supports key assumotion 1, shows how brain strucutres can lead to a change within the behaviour of humans