The cognitive anthropologist Ed Hutchins, in his book Cognition In The Wild depicts the general role of cognitive technologies in similar terms, suggesting that "[Such tools] permit the [users] to do the tasks that need to be done while doing the kinds of things people are good at: recognizing patterns, modeling simple dynamics of the world, and manipulating objects in the environment." This description nicely captures what is best about good examples of cognitive technology: recent word-processing packages, web browsers, mouse and icon systems, etc. (It also suggests, of course, what is wrong with many of our first attempts at creating such tools: the skills needed to use those environments (early VCR's, word-processors, etc.) were precisely those that biological brains find hardest to support, such as the recall and execution of long, essentially arbitrary, sequences of operations.

The conjecture, then, is that one large jump or discontinuity in human cognitive evolution involves the distinctive way human brains repeatedly create and exploit various species of cognitive technology so as to expand and reshape the space of human reason. We, more than any other creature on the planet, deploy non-biological elements (instruments, media, notations) to complement (but not, typically, to replicate) our basic biological modes of processing, creating extended cognitive systems whose computational and problem-solving profiles are quire different from those of the naked brain. Human brains maintain an intricate cognitive dance with an ecologically novel, and immensely empowering, environment: the world of symbols, media, formalisms, texts, speech, instruments and culture. The computational circuitry of human cognition thus flows both within and beyond the head.