For a period of some ten millennia, the stone-tool industries of North Africa were dominated by microlithic backed bladelets, sometimes almost to the exclusion of any other forms. They were made and used in very small, face-to-face, social contexts and so must have had a role in shaping and negotiating social identity. This can be best seen in the extreme consistency of their forms, both size and shape. Within each of the various cultural contexts, across half a continent, the backed bladelets are so unvarying as to raise the question of whether any determinants other than social negotiation were important. The answer seems to be that, like all things, such nonsocial factors remain possible, but they are very difficult to find.