Recently, there has been great interest in connecting archeological findings to knowledge and hypotheses about human cognitive evolution including the evolution of language. Dating back as far as 100 ka, the Blombos ochre and the Diepkloof ostrich egg engravings from South Africa are considered among the earliest fossilized evidence of human symbolic behavior. Of special interest is the temporal trajectory spanning more than 40 thousand years from earlier simpler parallel line patterns to later complex cross-hatchings suggesting an adaptive, compositional development. In a series of lab experiments, we investigate the “cognitive affordances” of patterns from different time points to test whether the development is an expression of an adaptive process of functional optimization for human perception and cognition. More concretely, we investigate if line carvings evolve over time to become more salient, reproducible, intentionally expressive and memorizable. Furthermore, we used the early line carvings as seeds in a transmission chain study to test if similar compositional developments can be experimentally elicited through serial reproduction. The experimental observations are used to inform discussions about the potential symbolic function of the original line engravings.