Work: A Deep History, from the Stone Age to the Age of Robots

by James Suzman

Genomic studies in the future may well offer some new insights into this. In the meantime, though, we have little option but to stare at objects like hand-axes and ask why, after making them diligently for a million years, our ancestors suddenly abandoned them 300,000 years ago in favor of more versatile tools made with a series of new techniques. One possible answer is that our ancestors were genetically shackled to hand-ax design in much the same way that different species of birds are genetically shackled to specific designs of nest. If so, Homo erectus and others diligently made hand-axes while operating on instinctive autopilot with only a vague sense of why,8 until some 300,000 years ago they suddenly crossed a critical genetic Rubicon that spontaneously ushered in a new era of innovation. Another possible answer reveals itself if we abandon the idea that intelligence is a single generalized trait and instead view it as a collection of different cognitive traits, which evolved, initially at least, to do different jobs in response to different adaptive pressures. Thus problem solving can be thought of as one form of intelligence responsive to a particular set of adaptive pressures, abstract reasoning another, spatial reasoning another, and the ability to acquire and absorb socially transmitted information another still. If so, then Homo erectus may have clung on so doggedly to the hand-ax design because the ability to learn from others was a far more beneficial adapta...