The scientific method is an empirical approach; this is where predictions are made and data is produced by observations and experiments, this is an advantage because you can know the truth about a theory due to evidence to support it, it does not require faith or belief.
Early psychologists such as Freud used subjective and unscientific methods; this has been criticized due to lack of objectivity. Therefore, indicating a historical shift towards an increasing emphasis on scientific approach, for example Viguera et al (2000) study on manic depression.
The scientific approach attempts to be objective, this is important because without an objective measure of variables, the validity of findings is uncertain. Therefore, the interpretation of what is to be observed is open to researcher bias. Variables are operationalized in order for studies to be objective. For example, Bandura operationalized aggression in children as punching, kicking, hitting, etc.
The preferred scientific research method is the laboratory experiment because it enables a cause and effect relationship to be established. In order to ensure that it is the changes in the IV that are…