Writing appears quite late in the human career. Modern humans appeared about 200,000 years ago; writing emerges 195,000 years later.

We might assume that this is the case because writing makes enormous demands: cognitive, social, and temporal resources must be stretched in the invention, propagation, and elaboration of written systems of communication.

R. Dale Guthrie, whose The Nature of Paleolithic Art challenges the assumption that cave paintings primarily treat of the supernatural, observes the playful nature of much cave art. Often, images of ancient game animals (and much less frequent human figures) found in the caves of the Dordogne are magnificent enigmas; far more abundant, however, are the sketches, essays, and incomplete doodles of casual ancient artists.

Guthrie thinks that much of what the Paleolithic artists were up to was play. Play is adaptive; it’s also addictive. Through it we learn to try new things, to predict outcomes and to comprehend the motives of others. Its pleasurability likely results from this instrumentality; yet it becomes an end in itself. Our playful activities take place on a razor’s edge between the dictates of natural selection and the costly wages of obsessive behavior.

It’s been widely observed that in many ways, humans evolved by degrees of infantilization. By extending the critical developmental periods to extremes, by making ourselves behave childishly as long as possible, our cognitive and social powers were extended into far-flung realms. And childhood play, remember, is not often simple: children love to elaborate rules; they concoct elaborate cants and mythologies of their own ephemeral devising. Like writing, play makes large demands. And yet humans do it all the time.

The question, then, is not why writing emerged, or how it managed to do so despite enormous odds against it. Instead it’s this: what took it so long?