L. Burton in "Causes of Polygyny: Ecology, Economy, Kinship, and Warfare", where the authors note: "Goody (1973) argues against the female contributions hypothesis. He notes Dorjahn's (1959) comparison of East and West Africa, showing higher female agricultural contributions in East Africa and higher polygyny rates in West Africa, especially in the West African savanna, where one finds especially high male agricultural contributions. Goody says, "The reasons behind polygyny are sexual and reproductive rather than economic and productive" (1973:189), arguing that men marry polygynously to maximize their fertility and to obtain large households containing many young dependent males." An analysis by James Fenske (2012) found that child mortality and ecologically-related economic shocks had a stronger association with rates of polygamy in Subsaharan Africa rather than female agricultural contributions (which are typically relatively small in the West African savanna and Sahel, where polygyny rates are higher), finding that polygyny rates decrease significantly in line with child mortality rates. Desire for progeny Most research into the determinants of polygyny has focused on macro-level factors. Widespread polygyny is linked to the kinship groups that share descent from a common ancestor. Polygyny also served as "a dynamic principle of family survival, growth, security, continuity, and prestige", especially as a socially approved mechanism that increases the number of adult workers immediately and the eventual workforce of resident children. According to scientific studies, the human mating system is considered to be moderately polygynous, based both on surveys of world populations, and on characteristics of human reproductive physiology. Economic burden Scholars have argued that in farming systems where men do most of the agriculture work, a second wife can be an economic burden rather than an asset. In order to feed an additional wife, the husband must either work harder himself or he must hire laborers to do part of the work. In such regions, polygyny is either non-existent or is a luxury which only a small minority of rich farmers can indulge. A report by the secretariat of the UN Economic Commission for Africa (ECA) quotes: "one of the strongest appeals of polygyny to men in Africa is precisely its economic aspect, for a man with several wives commands more land, can produce more food for his household and can achieve a high status due to the wealth which he can command". According to Boserup's 1970 studies, through the hard work, economic, and agricultural assistance of a