A person's morality establishes the actions they consider appropriate and inappropriate in their current society. Individuals belonging to the same socio-economic backgrounds tend to overlap and match each other. Other times, morals are non-existent or different due to a person's upbringing and culture. This means that decisions perceived as “appropriate” by some people may be considered “inappropriate” by others. Evil in terms of morality can be defined as a person's morality so extreme or nonexistent compared to that of modern society that it cannot be logically understood. Despite the effect of a person's morality and upbringing on their actions, in extreme cases the biology of the brain has a great effect on distinguishing between what is appropriate and what is not. There is a spectrum between good and evil, but not everything is black and white. For example, not leaving a good tip at a restaurant and pedophilia are both considered inappropriate, but pedophilia is much worse. A person who commits pedophilia does not do so simply because of external factors, but rather because something is wrong in their environment.