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,
Feathers: The Evolution of a Natural Miracle "Archaeopteryx" fossil specimen and the resulting debate between English paleontologist Richard Owen, an opponent to evolution by natural selection, and Thomas Henry Huxley, an advocate for evolution. Hanson himself visits the Wyoming Dinosaur Center, a small museum in Thermopolis, Wyoming, which had acquired an "Archaeopteryx" specimen. Hanson interviews Richard Prum, the Coe Professor of Ornithology at Yale University, who proposed a developmental theory of feather evolution, which focuses "on how feathers grow and not worrying about what they're used for." Hanson also interviews Alan Feduccia, a professor at the University of North Carolina, who disagrees with the scientific consensus that