A particular aspect of K. Hayles’ paper ‘Unfinished Work – From Cyborg to Cognisphere’ made me think:
on p.164  she ponders over co-evolutionary processes in which fundamental changes in the design in two unrelated areas such as biology and culture can have a profound effect on the evolutionary fitness of the organism, in this case H. sapiens.
She was of course referring to the the evolution of bipedalism and the opposing thumb, with the latter of course being associated with the advent of manual dexterity allowing the creation of simple stone tool and other artefacts.

In a further example she described another investigtion by Ambrose (2001)  an anthropologist who was researching the emergence of compound tools, consisting of for example wood, stone or horn tight together to a single instrument with plant fibrous material. He argues that the evelopment of this skill has been occuring at the same time as the accelerated development of an area of the brain (Broca’ aresa associated with language development.
He speculates that the particular skills invovled in complex tool making such as sequential and hierachical ordering of elements (stone sharpening first, handle making next, treating fibres next etc.) is also a quintessential way of learning a language. and as a result the two may have driven each other in a co-evolutionary spiral.
Tentative as this statement may be and there is little evidence to proof this it sheds some interesting light on current thinking on human-technology interaction, cyborg-type.
Are we now at a stage where the two are becoming so intertwined that one (human mental capacity) drives the ‘evolution’ of the other (complexity of technology), with the possibility of a positive feedback loop.
Clearly speech turned out to be the transformative skill over the last 20,000 years or so - and tool making remained a necessary but secondary side issue; what will dominante the current co-evolutionary event?

Ambrose, SH (2001) Paleolithic Technology and Human Evolution; Science 291 (5509), 1748-53
Hayles, NK (2006) Unfinished Work – From Cyborg to Cognisphere 23 (7-8), 159-166