C. Ray Jeffery explains what contributes to criminal behavior and asserts that sociological, psychological, and biological characteristics work together to produce criminal behavior. He says that two things that cause certain forms of behavior are that individuals are born with certain biological and psychological characteristics. Jeffery says poverty plays an important role in the development of individuals and indirectly causes criminal behavior. He says that diet and exposure to pollutants harm the brain because chemicals are changed in the brain from biochemicals to neurochemicals (Williams and McShane).