I loved the infographic, although it's clearly overly simplistic it does suggest a sense of where there is no claimed extent of a symbol-type, which might in some cases support broad patterns of domains of exchange. It generates interest.

The real linguistic question is not whether the art had representational value and thus was a form of communication: this is known and clear, simply through the frequent nature of pictographic forms of recognizable elements of the environment.

Rather, it is more to what extent there was a systematization of the pictographs through phonetic or phonosyllabic use, and to what extent any such symbol repetition indicates a depth of shared culture across spatiotemporal divides. At what point does it count as 'writing'?

In general, there was clearly shared culture (technology meant that options were somewhat limited, and we have traced major changes such as the ingress of dingoes from Asia to Australia). What we are learning recently is the hitherto dismissed extent to which disparate branches of hominids survived and persisted in pockets across time, how we mixed with them and adopted their features. IMHO grand colonial theories of migration (often patriarchic/single-event/unidirectional) are falling away as novel evidence such as mtDNA shows far longer admixture and pluralistic bidirectional flows of culture, genes and technology.

Personally, having seen some ancient cave paintings near the northern Burmese and Vietnamese borders as well as in Australia and most recently in a book on Baja California, the similarities are striking, but this does not mean people teleported across the globe. It seems early peoples globally worked a broadly similar techno-social palette to leave marks across time, persisting their identity and expression in ways which probably marked social presence, status, ritual and interpretation. Stories became written and illustrated, but only in summary. Usually we cannot recover the actual content because all that is left are cues, other times modern anthropology preserved traditional interpretation. We often see presumed or literal figures, animals (spirits? gods? prey? food?), weapons, abstract markings, celestial bodies. Things that would be notable in such a society. 20th century anthropology has shelves of studies on this stuff. Here in Sydney, a city of 4+ million people, there are many aboriginal sites with engravings of people, emu, fish, dolphins, turtles, whales, kangaroos, reptiles, etc. Further north, even far inland, there exists rock art of early European ships sighted on the coast, suggesting use for record, story-telling, teaching.