Being labelled as one "type" or another is often not something nice but everybody has a different personality: You love something that others might hate or get angry at something while some do not react at all. Every person has a unique personality but apparently American scientists are able to provide evidence for the existence of at least four personality types.

According to the new study published in the journal Nature Human Behavior, average, reserved, self-centered and role model are the main personality types listed and each one is based on the extent to which people display five different major character traits, including neuroticism, extraversion, openness, agreeableness and conscientiousness.

Professor Luis Amaral of Northwestern University who is the leading scientist of the study also offered comments on the personality types. "These are people that are nice, they are agreeable," said professor Amaral about "role models." "They are not neurotic and they are open-minded." They score highly on the other four traits.

Self-centered is almost the mirror-image of the role model, according to professor Amaral. "These are people that are not hard working, they are kind of disagreeable, they are not open minded. They are extroverts."

People who are filed under "reserved" have low neuroticism and low openness. However, they are likely to be conscientious and agreeable.

"There is very little to say about average," said professor Amaral. This type of personality fits the "typical" person. They score slightly above average on neuroticism and extroversion but lower on openness.

However, if you are not happy with your results, you do not need to be alarmed. According to the scientists people's personality types can change with age.