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)

Current theory-of-mind research faces the challenge of reconciling two sets of seemingly incompatible findings: Whereas children come to solve explicit verbal false belief tasks from around 4years of age, recent studies with various less explicit measures such as looking time, anticipatory looking, and spontaneous behavior suggest that even infants can succeed on some FB tasks. In response to this tension, two-systems theories propose to distinguish between an early-developing system, tracking simple forms of mental states, and a later-developing system, based on (...) fully developed concepts of belief and other propositional attitudes. One prediction of such theories is that the early-developing system has signature limits concerning aspectuality. We tested this prediction in two experiments. The first experiment showed that 2- and 3-year-olds take into account a protagonist's true or false belief about the location of an object in their active helping behavior. In contrast, toddlers' helping behavior did not differentiate between true and false belief conditions when the protagonist's belief essentially involved aspectuality. Experiment 2 replicated these findings with a more stringent method designed to rule out more parsimonious explanations. Taken together, the current findings are compatible with the possibility that early theory-of-mind reasoning is subject to signature limits as predicted by the two-systems account. (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.