They used ideographic or early mnemonic symbols or both to represent a limited number of concepts, in contrast to true writing systems, which record the language of the writer.
[2] Analysis in 2022, led by Bennet Bacon, an amateur archaeologist,[3] showed that lines, dots and "Y"-like symbols on Upper Palaeolithic cave paintings were used to indicate the mating cycle of animals in a lunar calendar.
[4][5] In 2003, turtle shells with carved inscriptions featuring a library of symbols were found in 24 Neolithic graves excavated at Jiahu in the northern Chinese province of Henan.
[10] During c. 3600 – c. 3200 BC, proto-writing in the Fertile Crescent was gradually evolving into cuneiform, the earliest mature writing system.
Various scholars believe that Egyptian hieroglyphs "came into existence a little after Sumerian script, and ... probably [were] ... invented under the influence of the latter ...",[11] although it is pointed out and held that "the evidence for such direct influence remains flimsy" and that "a very credible argument can also be made for the independent development of writing in Egypt ..."[12] During the Bronze Age, the cultures of the Ancient Near East are known to have had fully developed writing systems, while the marginal territories affected by the Bronze Age, such as Europe, India and China, remained in the stage of proto-writing.
Interpretations of the markings of the bronze sickles associated with the Urnfield culture, especially the large number of so-called "knob-sickles" discovered in the Frankleben hoard, are discussed by Sommerfeld (1994).
[14][full citation needed] Even after the Bronze Age, several cultures have gone through a period of using systems of proto-writing as an intermediate stage before the adoption of writing proper.