In 1964, John Maynard Smith, C. M. Perrins (1964), and George C. Williams in his 1966 book Adaptation and Natural Selection cast serious doubt on group selection as a major mechanism of evolution; Williams's 1971 book Group Selection assembled writings from many authors on the same theme.
En 1964, John Maynard Smith, e George C. Williams no seu libro de 1966 Adaptation and Natural Selection puxeron en dúbida a selección de grupo como mecanismo importante na evolución; o libro de Williams de 1971 Group Selection reuniu os escritos de moitos autores sobre ese tema.