When European explorers of the Enlightenment encountered population differences among Pacific Islanders, a major and long-lasting division was drawn between Polynesians and Melanesians. While Polynesians inhabiting the eastern Pacific had a physical appearance, languages and cultural institutions suggestive of a relatively recent, common ancestry from Island Southeast Asia, Melanesians exhibited diverse sociobiological traits indicative of a much longer occupancy, in what the geographer Charles de Brosses in 1756 termed the equatorial “torrid zone”, that had been settled in the distant past by people of African origin. The different population origins (Asiatic and Negroid) and tenure length of the two groups in the Pacific were thought to divide Melanesians starkly from Polynesians (Tcherkézoff 2003), and a simple binary model of human diversity was further developed in 19th-century socioevolutionary thought as a polar opposition between light brown–skinned, culturally advanced Polynesians and the dark-skinned Melanesians, who were condemned by authorities such as Dumont d’Urville (2003) as living in a primitive state of near-barbarism.
Within this framework, the position of Micronesians was uncertain, but many early reports stated that western Micronesians had a physical appearance suggesting derivation from Island Southeast Asia, while the populations of central and eastern Micronesia were more diverse, but grouped closer to Polynesians than to Melanesians. Horatio Hale (1846) found the physical characteristics of Micronesians did not vary greatly from their neighbours in Polynesia (also Haddon 1909: 22), while d’Urville (2003) thought Micronesia was populated by a series of migrations out of the Philippines after Polynesia had been colonised. This would have migrants from Island Southeast Asia arriving in western Micronesia with subsequent dispersals to central and eastern Micronesia (Map 1.38.1), possibly through Kiribati and Tuvalu, to Polynesia. W. W. Howells (1973) followed P. Buck (1958) in suggesting that early Polynesians had probably come from Micronesia, given the greater physical similarity of Micronesians and Polynesians to one another than either had to Melanesian populations.