Drivers of intelligence evolution in Homo: Sexual behavior, food acquisition and infant neoteny

Journal/Book: Mankind Quart. 1998; 39: 1133 13Th St NW, #C-2, Washington, DC 20005, USA. Inst Study Man. 127-146.

Abstract: There are many hypotheses on language and IQ evolutions, but many failed to explain sex differences of IQ. Some discussions presuppose that only Homo has language and that this appeared suddenly. Molecular level evolution does not support any sudden appearance of language. Bipedality amongst Homo was a factor in the evolution of many modem aspects of Homo; changes in copulation behavior contributed to the evolution of language; bipedality produced a larger brain, but blocked enlargement of the parturient canal and retarded further increases in the size of the brain. The female Homo was forced to deliver the neonate in a state of neoteny. Females further evolved language in order to take care of the infants. Male Homos accelerated food acquisition activities to provide the energy required to maintain a larger brain. The male Homo lost the initiative in sexual intercourse at female's mating season and began to depend on language from the female as a signal for mating. Females who acquired the initiative in copulation begun to select male partners by their ability to provide food and security. By this sexual selection, the evolution of language was accelerated. Neoteny, although physically disadvantageous, assisted neural development. Homo developed the ability to accumulate more information, a process in which language played a crucial role.

Note: Article Hattori K, Natl Rehabil Ctr Disabled, 4-1 Namiki, Tokorozawa, Saitama 3590042, JAPAN

Keyword(s): Homo Sapiens; evolution; language; neural development; intelligence; bipedality; copulation; BRAIN; PERFORMANCE; FEMALES; IQ

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