 According to strain theory, differences in crime rates between races are the result of real differences in behavior, but to be understood as an attempt to alleviate either absolute or relative deprivation and adapt to the existing opportunity structure.A more recent approach to strain theory was proposed by Steven F. Messner and Richard Rosenfeld in the 1990s.In their version of the theory, which they refer to as institutional anomie theory, Messner and Rosenfeld argue that the dominance of materialistic concerns and measurements of success manifested in the American Dream weakens the effectiveness of informal social control mechanisms and support processes, which encourages economic gain by any means, legal or illegal.