The zone of latent solutions hypothesis provides an alternative approach to explaining cultural patterns in primates and many other animals. According to the ZLS hypothesis, non-human great ape cultures consist largely or solely of latent solutions. The current competing hypothesis for ape culture argues instead that at least some of their behavioural or artefact forms are copied through specific social learning mechanisms and that their forms may depend on copying. In contrast, the ape ZLS hypothesis does not require these forms (...) to be copied. Instead, it suggests that several social learning mechanisms help determine the frequency of these behaviours and artefacts within connected individuals. The ZLS hypothesis thus suggests that increases and stabilisations of a particular behaviour’s or artefact’s frequency can derive from socially-mediated form reinnovations. Therefore, and while genes and ecology play important roles as well, according to the ape ZLS hypothesis, apes typically acquire the forms of their behaviours and artefacts individually, but are usually socially induced to do so. The ZLS approach is often criticized—perhaps also because it challenges the current null hypothesis, which instead assumes a requirement of form-copying social learning mechanisms to explain many ape behavioural forms. However, as the ZLS hypothesis is a new approach, with less accumulated literature compared to the current null hypothesis, some confusion is to be expected. Here, we clarify the ZLS approach—also in relation to other competing hypotheses—and address misconceptions and objections. We believe that these clarifications will provide researchers with a coherent theoretical approach and an experimental methodology to examine the necessity of form-copying variants of social learning in apes, humans and other species. (shrink)

In 2009, Tennie et al. proposed the theory of the Zone of Latent Solutions, defined as the range of behaviors an individual of a species can invent independently, i.e., which it can acquire without any form of social learning. By definition, species limited to their ZLS are unable to innovate and/or transmit behavioral traits outside their ZLS, i.e., they lack traits which go beyond the level of the individual—traits resulting from a gradual cultural evolution over successive transmission events [“cumulative culture”, (...) Boyd and Richerson ]. However, this does not exclude an influence of social learning on the population frequency of these behaviors: social learning can facilitate the acquisition of latent solutions and thus speed up and consolidate their spread within a population. Cultures—defined as behaviors at least influenced by social learning—are therefore still possible. Here, we elaborate on the ZLS account and relate it to the theories of Vygotsky who studied the role of social learning in human culture. We argue that the ZLS is a missing phylogenetic “baseline” of Vygotsky’s Zone of Actual Development. Vygotsky’s neglect of a need for a human “baseline ZAD” may have been due to his interpretation of Köhler’s work on great ape behaviors: Köhler used his observations on individual chimpanzees to draw conclusions about the chimpanzee species as a whole, stating that chimpanzees can only copy what they could have invented themselves, thus coming close to the ZLS concept. Vygotsky—studying the range of behaviors individuals could achieve independently—seemingly did not see that Köhler was suggesting a species “baseline”, upon which Vygotsky’s idea of an individual’s ZAD could develop. As a result, Vygotsky also did not see the need for a ZLS for his own study subjects: humans. Yet, there is no reason to assume that humans lack a ZLS, and in fact we present evidence for a human ZLS for tool-use behaviors. (shrink)

The critical examination of current hypotheses is one of the key ways in which scientific fields develop and grow. Therefore, any critique, including Haidle and Schlaudt’s article, “Where Does Cumulative Culture Begin? A Plea for a Sociologically Informed Perspective,” represents a welcome addition to the literature. However, critiques must also be evaluated. In their article, Haidle and Schlaudt review some approaches to culture and cumulative culture in both human and nonhuman primates. H&S discuss the “zone of latent solutions” hypothesis as (...) applied to nonhuman primates and stone-toolmaking premodern hominins. Here, we will evaluate whether H&S’s critique addresses its target. (shrink)

To support their claim for technical reasoning skills rather than imitation as the key for cumulative technological culture, Osiurak and Reynaud argue that chimpanzees can imitate mechanical actions, but do not have CTC. They also state that an increase in working memory in human evolution could not have been a key driver of CTC. We discuss why we disagree with these claims.