A number of later writers, such as the French anthropologist Vacher de Lapouge in his book L'Aryen, argued that this superior branch could be identified biologically by using the cephalic index (a measure of head shape) and other indicators.
The German origin of the Aryans was especially promoted by the archaeologist Gustaf Kossinna, who claimed that the Proto-Indo-European peoples were identical to the Corded Ware culture of Neolithic Germany.