According to Maslow (1950) we all strive for self-actualisation, which is that we move towards freewill. However it's been found that maladaptive behaviour results from lack of acceptance of oneself which prevents Maslow's self-actualisation occurring, therefore not everyone can strive for it, after all there are individual differences.
Freewill has been used as a defence in murder, some say that something which is beyond their control has determined them to kill someone i.e. inherited bad temper genes. But the freewill argument will be supported by diminished responsibility in law, because it shows that most behaviour is free, only those who are mentally ill and children have determined behaviour.
More supporting evidence for the existence of freewill comes from Penfield (1947); he stimulated parts of the brain of patients about to undergo brain surgery, to make them feel as though their limbs were moving. Penfield found that his patients said they felt different when their limbs moved when being coerced and when they moved them by their own freewill. Therefore freewill is a subjective feeling and most people believe they have freewill and this feeling supports this. One criticism to this is behaviourists such as Skinner would say that this subjective feeling of being free is just an illusion.