Evolved Open-Endedness in Cultural Evolution: A New Dimension in Open-Ended Evolution Research.

The goal of Artificial Life research, as articulated by Chris Langton, is "to contribute to theoretical biology by locating life-as-we-know-it within the larger picture of life-as-it-could-be." The study and pursuit of open-ended evolution in artificial evolutionary systems exemplify this goal. However, open-ended evolution research is hampered by two fundamental issues: the struggle to replicate open-endedness in an artificial evolutionary system and our assumption that we only have one system (genetic evolution) from which to draw inspiration. We argue not only that cultural evolution should be seen as another real-world example of an open-ended evolutionary system but that the unique qualities seen in cultural evolution provide us with a new perspective from which we can assess the fundamental properties of, and ask new questions about, open-ended evolutionary systems, especially with regard to evolved open-endedness and transitions from bounded to unbounded evolution. Here we provide an overview of culture as an evolutionary system, highlight the interesting case of human cultural evolution as an open-ended evolutionary system, and contextualize cultural evolution by developing a new framework of (evolved) open-ended evolution. We go on to provide a set of new questions that can be asked once we consider cultural evolution within the framework of open-ended evolution and introduce new insights that we may be able to gain about evolved open-endedness as a result of asking these questions.

The structure of executive functions in preschool children and chimpanzees.

Executive functions (EF) are a core aspect of cognition. Research with adult humans has produced evidence for unity and diversity in the structure of EF. Studies with preschoolers favour a 1-factor model, in which variation in EF tasks is best explained by a single underlying trait on which all EF tasks load. How EF are structured in nonhuman primates remains unknown. This study starts to fill this gap through a comparative, multi-trait multi-method test battery with preschoolers (N = 185) and chimpanzees (N = 55). The battery aimed at measuring working memory updating, inhibition, and attention shifting with three non-verbal tasks per function. For both species the correlations between tasks were low to moderate and not confined to tasks within the same putative function. Factor analyses produced some evidence for the unity of executive functions in both groups, in that our analyses revealed shared variance. However, we could not conclusively distinguish between 1-, 2- or 3-factor models. We discuss the implications of our findings with respect to the ecological validity of current psychometric research.

Exploring the development of attentional set shifting in young children with a novel Intradimensional/Extradimensional shift task.

Attentional set shifting is a core part of cognition, allowing quick and flexible adaption to new demands. The study of its development during early childhood has been hampered by a shortage of measures not requiring language. This article argues for a revival of the Intradimensional/Extradimensional (ID/ED) shift task by presenting a new nonverbal version of the task (Shifting Tray task). Children (N = 95 3- to 5-year-olds; 49 girls; predominantly European White) were presented with pairs of trays, each filled with a substrate and an upside-down cup on top, and were asked to find stickers. In the pre-switch phase, children learned (through trial and error) which dimension (substrate or cup) was predictive of the rewards. In the post-switch phase, all stimuli were exchanged. For children in the intradimensional shift condition, the dimension predictive of the sticker was the same as the one predictive in the pre-switch phase. For children in the extradimensional shift condition, the previously irrelevant dimension was now relevant. Results showed that most 3-year-olds were able to switch, and older children did not outperform younger children. The easy and flexible nature of the task allows researchers to investigate the impact of labels and instructions and to use it in cross-cultural and comparative research.

Thinking inside the box: Mental manipulation of working memory contents in 3- to 7-year-old children.

We developed a non-verbal task assessing updating and manipulation of working memory contents. 80 3- to 7-year-olds (47 girls; predominantly European White) were tested with a 4 × 4 grid containing 8 boxes (in the 4 centre cells and 4 outer corners). A sticker was hidden and children searched for it after a delay phase. In the updating trials, the grid was rotated during delays, in the manipulation trials, the grid was both occluded and rotated. Rewards were hidden in either the inner or outer boxes (between-subjects design). Performance was affected by age, rotation degree and hiding condition. Performance was better in outer boxes trials, where visual tracking was easier. Occluded inner trials added a substantial cognitive load (which increased with degree of rotation), resulting in children performing at chance level, suggesting that manipulation involving mental rotation is a distinct skill from tracking invisible object displacement, with a more protracted development.

The technical reasoning hypothesis does not rule out the potential key roles of imitation and working memory for CTC.

To support their claim for technical reasoning skills rather than imitation as the key for cumulative technological culture (CTC), 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.

A cross-cultural investigation of young children's spontaneous invention of tool use behaviours.

Through the mechanisms of observation, imitation and teaching, young children readily pick up the tool using behaviours of their culture. However, little is known about the baseline abilities of children's tool use: what they might be capable of inventing on their own in the absence of socially provided information. It has been shown that children can spontaneously invent 11 of 12 candidate tool using behaviours observed within the foraging behaviours of wild non-human apes (Reindl et al. 2016 Proc. R. Soc. B 283, 20152402. (doi:10.1098/rspb.2015.2402)). However, no investigations to date have examined how tool use invention in children might vary across cultural contexts. The current study investigated the levels of spontaneous tool use invention in 2- to 5-year-old children from San Bushmen communities in South Africa and children in a large city in Australia on the same 12 candidate problem-solving tasks. Children in both cultural contexts correctly invented all 12 candidate tool using behaviours, suggesting that these behaviours are within the general cognitive and physical capacities of human children and can be produced in the absence of direct social learning mechanisms such as teaching or observation. Children in both cultures were more likely to invent those tool behaviours more frequently observed in great ape populations than those less frequently observed, suggesting there is similarity in the level of difficulty of invention across these behaviours for all great ape species. However, children in the Australian sample invented tool behaviours and succeeded on the tasks more often than did the Bushmen children, highlighting that aspects of a child's social or cultural environment may influence the rates of their tool use invention on such task sets, even when direct social information is absent.

Young children fail to generate an additive ratchet effect in an open-ended construction task.

The ratchet effect-the gradual accumulation of changes within a cultural trait beyond a level that individuals can achieve on their own-arguably rests on two key cognitive abilities: high-fidelity social learning and innovation. Researchers have started to simulate the ratchet effect in the laboratory to identify its underlying social learning mechanisms, but studies on the developmental origins of the ratchet effect remain sparse. We used the transmission chain method and a tower construction task that had previously been used with adults to investigate whether "generations" of children between 4 and 6 years were able to make a technological product that individual children could not yet achieve. 21 children in a baseline and 80 children in transmission chains (each consisting of 10 successive children) were asked to build something as tall as possible from plasticine and sticks. Children in the chains were presented with the constructions of the two preceding generations (endstate demonstration). Results showed that tower heights did not increase across the chains nor were they different from the height of baseline towers, demonstrating a lack of improvement in tower height. However, we found evidence for cultural lineages, i.e., construction styles: towers within chains were more similar to each other than to towers from different chains. Possible explanations for the findings and directions for future research are suggested.

Are there signature limits in early theory of mind?

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 (FB) 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 (in line with previous findings) 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.