Conclusive proof is lacking as to whether harsh sentences actually deter crime. The most obvious result of harsh sentencing is the disruption of the black community, particularly as it bears on young black men. A substantial minority of both white and black teenage boys engage in violent behavior. In their twenties, most whites give up violence as they take on the responsibility of jobs and families, but a disproportionate number of African-Americans do not have jobs, and they are most likely to contribute to crime and imprisonment rates. One in seven adult black males has lost his voting rights because of a felony conviction.
Imprisonment thus becomes a negative reward, in contrast to the positive reward of wealth.
The theory perhaps explains why the U.S. has higher incarceration rates than other Western countries, where income inequality is less extreme, and why rates began to rise in the early 1970s, shortly after income disparities began rising. If the theory is correct, high U.S. incarceration rates are unlikely to decline until there is greater equality of income.