Many psychological approaches would agree that behaviour is largely pre-determined but disagree on the determinants of human behaviour.The biological approach displays physiological determinism at is believes that behaviour is determined by our genes. This is advantageous because the approach is supported by scientific research where there is control over the IV and DV thus making treatments quicker and more effective. One effective drug is clozapine, used to reduce the symptoms of schizophrenia by blocking serotonin and dopamine in neurotransmitters as suffers cant control themselves. This proves schizophrenia is determined by brain structure.The behaviourist approach displays environmental determinism due to its argument that behaviour is learnt from the environment through operant and classical conditioning and modelling. This explains anorexia which proposes that body image is shaped by the media. However, Mischel suggests an interaction between the individual and the environment is important. A person will chose a social environment to suit them and will learn behaviour from their social group. Therefore, it can be argued that learnt behaviour is partially due to choice and thus free will. The behaviourist approach also show reductionism as it reduces complex behaviour to simple stimulus responses which isnt the only factor which will affect humans behaviour.In contrast, the cognitive approach supports free will as it believes that our schemas are developed from our interactions with the world and our experiences and these schemas drive our behaviour. Therefore, these thought processes can be altered. Dobash supports this as he tested the effectiveness of CBT in anger management and found that individuals were able to reduce aggression thus control their behaviour. This shows a person has free will over behaviour.As psychological research evolves, we are able to prove more assumptions and attempt to solve the debate. Prices XYY research into criminality gave an explanation of violent crimes based on chromosome abnormality. He found that males with an extra Y chromosome were more likely to commit crime than those with the normal XY chromosomes. This research is beneficial because is it scientific and gives a cause and effect. Also, it can help to give an early diagnosis of mental disorders.There are many psychological arguments supporting free will. Dr Samuel Johnson believes that people have a subjective sense of free will and so feel that they possess it, therefore, individuals feel responsibility for their actions. However, free will has found to be a difficult concept to be defined. Valentine has proposed a number of explanations of free will. The first is choice, where in a given situation a person can chose to act differently to the way they did. The second is uncaused behaviour where behaviour is random, but this would make behaviour unpredictable. The third is voluntary behaviour. Furthermore, theres no proof free will exists, we may only think were free due to the causes of our behaviour being hidden from us.The moral responsibility argument states that and individual must have free will because we are responsible for our own actions. Our legal system is based on this. Furthermore, research into criminality suggests there may be a biological basis. Prices XYY research into criminality gave an explanation of violent crimes based on chromosome abnormality. He found that males with an extra Y chromosome were more likely to commit crime than those with the normal XY chromosomes. However, this has implications as it suggests we have no control over developing criminality. Our justice system is based on free will, so therefore, criminals will be able to blame criminal behaviour on their genes.There are also psychological arguments for supporting determinism. The scientific argument suggests that determinism is compatible with science because science can give cause-effect relationships so we can then begin to predict and control behaviour. A problem with this is that most scientific research is conducted in labs so cannot be generalised to the real world. Also, it relies on the idea that human behaviour is 100% predictable but Mischels theory of personality argues that people behaviour varies in different situations so behaviour isnt consistent and thus not predictable. Research into the human genome project is producing evidence of genes effecting behaviour. Zubrenko has identified a gene for depression proving it may be pre-determined. However, its gender specific and can only be applied to females. There will never be 100% genetic determinism due to the ethical implications involved. People may begin to create designer babies that have no genetic abnormalities or any of the genes that may lead to abnormality in behaviour. This would cause many ethical issues and problems for society. A major concern would be the issues related with labelling as people may be treated unequally e.g. insurance companies might not insure a person if they are carrying a mental illness gene.