The first study by a psychologist on the effects of environment on child-chimp differences was conducted by a Russian, Nadia Kohts in the 1920s. (See the story of Kohts in Hahn, 1988 and reviews of women involved with apes in Haraway (1988) and Parker and Gibson, 1990). The first home- raised chimp experiment in the USA was done by Winthrop and Luella Kellogg (1933/1967), who were at the University of Indiana.
"Why not give one of the higher primates exactly the environmental advantages which a young child enjoys and then study the development of the resulting organism?"
While a number of people raised chimps in their home, none went about a systematic comparison of ape-child development as did the Kelloggs.
"It should be clear, therefor, that, as far as Gua is concerned, an increased rate of maturation parallels to a considerable extent an increased rate of learning." [They point out a similar relation between boys and girls in elementary school!]
Gua had virtually no speech despite her advanced maturation. "it is unlikely any anthropoid ape will ever be taught to say more than a half a dozen words..if..this.p.289" The Kelloggs attribute this to "the ape's deficiency in a certain brain region known as Broca's area." They also pointed out that Gua never spontaneously vocalized like Donald and that this babbling was probably essential to subsequent speech. In contrast Gua appeared to comprehend utterances more quickly at first and at the end of the 9 months, Donald was only slightly ahead "their respective abilities measured 68 (words or phrases) for Donald and 58 for Gua. p.292" They have a detailed record on speech comparisons, mostly comprehension, in the book.
Gua was "astonishingly sensitive to even the weakest of stimuli...how responsive must these animals be to the extreme forms of punishment and deprivation employed in many of the ordinary types of experiments performed upon them...Who indeed, has thoroughly considered the point of view of the animal?...To test a captive anthropoid seized by force in the jungle, kept later in a cage, and motivated by hunger in some particular experiment is one thing. To test a human child who is kindly and gently talked to and who is never under any circumstances caged or starved is certainly a very different thing.
References Hahn, E. (1988). Eve and the apes. New York: Weidenfeld and Nicolson. Haraway, D. (1989). Primate visions: Gender, race, and nature in the world of modern science. New York: Routledge. Kellogg, W. N., Kellogg, L. A. (1933/1967). The ape and the child (Facsimile of the 1933 edition ed.). New York: Hafner Publishing Company. Parker, S. T., & Gibson, K. R. (Ed.). (1990). Language and intelligence in monkeys and apes. Cambridge: Cambridge University P http://www.eolas.ca/oculomtr/Anatomy/Anat_4.htmress. http://www.psy.fsu.edu/history/wnk/ape.html (see this for much more video and info)