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,
Unnatural Selection: Why the Geeks Will Inherit the Earth have geek-like powers, fostering a cognitive arms race’. ‘For the first time in human history,’ Roeder wrote, ‘humans will have the capacity to chart their own evolution - as the process of Darwinian natural selection is superseded by unnatural selection.’ He warns that 'human enhancement technologies will eventually threaten our sense of identity as human beings.' Steve Silberman, an editor of "Wired" magazine, wrote that Unnatural Selection ‘is a provocative book that explains why (geeks) have become a social force driving a new kind of human evolution.’ Author Daniel Wilson suggested that the book ‘paints a compelling picture of human