from two essays on the origins of the aesthetic impulse in Becoming Human: Innovation in Prehistoric Material and Spiritual Culture:
The earliest current evidence for handaxes comes from West Turkana, Kenya, dated to 1.65 Mya [Million years ago]. Similar finds have been made at Konso, again in Ethiopia, dating to 1.5 Mya. These tools show both lateral and bifacial symmetry, thus demonstrating early human acquisition of the notion of symmetry. Soon after this, the Acheulean culture produced perfectly symmetrical and very regular tools, sometimes with the choice of rocks of a pleasing color for their fabrication. Symmetry and color do not affect the functional effectiveness of a tool. This means that humans were looking for beauty and that they developed an appreciation for a job well done. Hominization thus passed a new threshold in the path towards greater complexity: the emergence of the sense of harmony.
The remarkable patterns incised on the small, carefully shaped block of red ochre at Blombos [Cave, South Africa, dated 70,000 years ago], for all their modesty, have comparably significant implications. They are not representational—to call them “art” might be too ambitious: patterning is a sufficiently grand term. But here are markings, deliberately made by a human being, which we may at least regard as “expressive”. They mark the first step of what Merlin Donald has termed “external symbolic storage”. Meaningful marks are being made upon some object, so that their meaning can be revisited at a later date when that object is returned to. For the first time, a device is being created where elements of memory may be stored outside the brain. Of course the various tools that humans had made, well before that time, would have carried various memories with them or at least were able to kindle such memories in their maker on subsequent occasions. But they remained tools. Here we see the beginning of deliberate markings, which we can regard as the starting point in the long process which led to the development of art in the Upper Paleolithic period, and very much later, to writing.