Sociocultural evolution justify new policies such as eugenics. Most 19th-century and some 20th-century approaches aimed to provide models for the evolution of humankind as a single entity. However, most 20th-century approaches, such as multilineal evolution, focused on changes specific to individual societies. Moreover, they rejected directional change (i.e. orthogenetic, teleological or progressive change). Most archaeologists work within the framework of multilineal evolution. Other contemporary approaches to social change include neoevolutionism, sociobiology, dual inheritance theory, modernisation theory and postindustrial theory. In his seminal 1976 book "The Selfish Gene", Richard Dawkins wrote that "there are some examples of cultural evolution in birds and monkeys,
Gene-centered view of evolution for the evolution of social characteristics such as selfishness and altruism. The formulation of the central dogma of molecular biology was summarized by Maynard Smith: The rejection of the inheritance of acquired characters, combined with Ronald Fisher the statistician, giving the subject a mathematical footing, and showing how Mendelian genetics was compatible with natural selection in his 1930 book "The Genetical Theory of Natural Selection". J. B. S. Haldane, and Sewall Wright, paved the way to the formulation of the selfish-gene theory. For cases where environment can influence heredity, see epigenetics. The view of the gene as the unit of