William Calvin's assumption that early Homo sapiens was more stupid than modern humans is based on prejudice, not evidence ("Brainier - but not smarter", February 25).
Calvin concludes that significant technological development did not occur for more than 100,000 years after Homo sapiens achieved its present brain size. He then implicitly assumes that technology is a hallmark of innate intelligence rather than cultural learning. Indeed, Calvin's interpretations, which lack evidence, come out of the same ilk as cultural imperialist attitudes down the ages that have assumed that because people have less effective (military?) technology they are stupid compared with "us".
Calvin's work de-linking brain size with technological development is excellent, but he has fallen into the classic positivist trap of assuming that his own empiricist approach is divorced from cultural value judgements. I suggest that he reads Foucault, Latour and Said as a corrective exercise.
David Toke
Department of sociology
Birmingham University