Frans BM de Waal, Christophe Boesch, Victoria Horner, and Andrew Whiten at the website of Emory University:
A recent study in Science by Esther Herrmann et al (7 September 2007, p. 1360) claims equivalence in technical skills between apes – chimpanzees and orangutans – and two-year-old human children, but inferior social skills in the apes. These results are taken as support for a “cultural intelligence hypothesis.”
The study features an impressive battery of tests, seemingly administered in the same format to apes and children. It has been pointed out before, however, that the easiest way to standardize conditions – by having a human experimenter provide the social cues – introduces handicaps for the apes. When the experimenter is human for all subjects, only the apes are dealing with a species other than their own. This may not be as relevant for physical or technical problems, which focus on inanimate objects, but one expects this to matter for social tasks which rely crucially on the relation between experimenter and subject. The reported findings are consistent with the apes being handicapped specifically in the social domain.
The differences between the set ups for children and apes in this study appear multifold. Human children sit on or next to their parent (introducing potential “Clever Hans” effects), are talked to, are used to dealing with human strangers, and are tested by a member of their own species. The apes are alone, observe the task from behind a barrier, receive no verbal instructions, and are tested by a species not their own. We are not suggesting that human experimenters should never be used, but that the social skills which matter most for apes, especially as they relate to culture, are those shown with conspecific models.
More here.