Strain theory was developed by Robert K. Merton in the 1950s and has been used in sociology and criminology. The theory states says that structures in society may cause individuals to feel pressure that is at the root of their criminal behaviors. For example, society may make individuals feel that they have to achieve the American Dream, so they may commit crimes such as theft to achieve the appearance of wealth or success. General Strain Theory, developed by Robert Agnew in the 1990s, states that an individual who feels strain may feel stress that motivates them to commit a crime. This theory considers a broad range of stressors rather than just concentrating on the attainment of wealth as earlier theories did. For example, if someone were hungry, this would cause the individual to feel negative stimuli. To remove this negative stimuli, the person would be motivated to steal bread.