As noted above, the Boasian tradition in cultural anthropology stressed how culture directed cognition. One common example was colour terms. The Boasians argued that all humans could see the same spectrum of colour, but since this was a continuum, the way the spectrum was broken up varied from culture to culture. This belief was shown to be quite false in a famous book by Berlin and Kay (1969), and in subsequent studies which showed that there was nothing arbitrary about how the spectrum was divided and that variation between cultures was strictly limited. This study was the first of many which revealed that in many key areas which cultural anthropologists had assumed were variable, all human cultures used the same cognitive principles. These findings were linked by certain anthropologists with advances in linguistics which suggested that the ability to learn human-type languages was the result of genetic programming common to all humans. Some anthropologists suggested that this was true for many areas of culture such as plant and animal *classification, concepts of the *person and of social relationships and face recognition; and even that certain types of narratives were easily learnt because they corresponded to genetic predispositions to remember them while others which did not mesh with the cognitive dispositions would soon be forgotten (Sperber 1985). If proved right, clearly these theories would inevitably lead to fundamental revisions in anthropological notions of culture and *society.