Published in 1994, The Bell Curve caused uproar. Herrnstein and Murray claim that intelligence is the key factor in determining success in life and that it is genetic and, more controversially still, that some ethnic groups are more intelligent than others. Herrnstein and Murray argue that black Americans are one of the most disadvantaged groups in American society not because of unjust social and economic systems or a history of oppression, but that black Americans live impoverished lives simply because they lack the intelligence to advance themselves. Liberals raged against these ideas, while conservatives praised the authors for voicing important, if controversial, arguments.