Human brains are basically primate in design, but in addition have rep
resentational mechanisms that give human consciousness a special chara
cter. The evolution in hominids of new kinds of representational skill
-both nonverbal and verbal-produced our capacity for skilled rehearsal
and explicit memory retrieval, and allowed the invention of conventio
nal, or public representations, including languages and external symbo
ls. The latter have created demands at the cultural level that greatly
influence the deployment of cerebral resources. The spiralling intera
ction of brain and culture in evolution has resulted in a unique quasi
-modular architecture at the highest levels of human cerebral integrat
ion.