Weakness - Liberty (1985) found that brain activity that determines the outcome of simple choices may predate our knowledge of having made that choice
The brain area lights up on the corresponding side up to 10 seconds before patients make a choice on whether to press a button with the left or right hand
This evidence suggests that activity and behavioural choices are determined genetically by the brain (some researchers have argued this activity is just to prepare the body for movement, not before a decision is made)