Each person is free to choose the beliefs to accept and those to reject. Therefore, there are more than 6 billion belief systems in the world and no two are identical. The frontal lobe is critical in directing our ability to act freely and make decisions. One may have less conscious choice that ordinarily believed, however. Studies by Benjamin Libet showed that several milliseconds before a person makes a conscious decision, there is electrical activity in the brain that likely represents a subconscious generation of the thought the person is about to have. Which means that humans are likely not responsible for every thought that crosses their mind. They likely are responsible for the thoughts they continue to harbor and cogitate upon once the thought reaches conscious awareness.