What is culture? Culture requires at least one variant of a “social learning” mechanism to influence at least the frequency – or even the form (the specific design) – of behaviours or artefacts in a population. Previous research has argued that similar social learning mechanisms underlie modern human and early hominin technology. However, early hominin culture shows periods of stasis, where modern human culture is instead cumulative – even explosive. This cumulative culture is powered and enabled by special variants of social learning mechanisms – namely those that can copy forms. Form copying even necessarily leads to cumulative culture - leading to “path-dependent” form changes and, eventually, to a complete dependency of the resulting form variants on copying (copying-dependent forms). It follows that the assumption of the early presence of these specific copying skills therefore is at odds with the observed patterns of stasis for early stone tools.
Instead of copying even copying-dependent forms from others (as modern humans do), contemporary ape cultures are based on non-copying variants of social learning. These variants still produce cultural patterns as they mediate the relative frequencies of forms between populations. Yet, ape cultures are based on and fuelled by "socially mediated individual reinnovations" instead of form copying. These reinnovations consist of forms that apes can in principle recreate on their own (“latent solutions”; Tennie et al. 2009, 2020). Again, unlike copying, such learning do not lead to culture-dependent forms. This latent solutions approach is thus a core candidate to account for early hominin stone tools because it provides an actual explanation for the stasis observed in the early stone tool archaeological record.
The STONECULT project tested whether early stone tools may be most parsimoniously regarded as manifestations of cumulative culture or whether they are best accounted for by the latent solutions model. STONECULT evaluates whether early stone tools were more similar either to modern ape (i.e. restricted to latent solutions) or modern human technologies (i.e. form-copying-dependent cumulative culture). In this way, STONECULT aimed help pinpoint when cumulative culture first started in our lineage.
Using a general triangulation of the question, STONECULT tested for latent solutions underlying early stone tools across three objectives/approaches. Objective 1 tested apes, while Objective 2 tested modern humans, for early stone tool reinnovations. Objective 3 was designed to tested for the unintentional, automatic production of more specific, later stone tool forms via the unsupervised outputs of an automatic "virtual knapper" software program that the STONECULT project was supposed to create.
