In the last decade, cultural transmission experiments (transmission chains, replacement, closed groups and seeded groups) have become important experimental tools in investigating cultural evolution. However, these methods face important challenges, especially regarding the operationalization of theoretical claims. In this review, we focus on the study of cumulative cultural evolution, the process by which traditions are gradually modified and, for technological traditions in particular, improved upon over time. We identify several mismatches between theoretical definitions of cumulative culture and their implementation in cultural transmission experiments. We argue that observed performance increase can be the result of participants learning faster in a group context rather than effectively leading to a cumulative effect. We also show that in laboratory experiments, participants are asked to complete quite simple tasks, which can undermine the evidential value of the diagnostic criterion traditionally used for cumulative culture (i.e. that cumulative culture is a process that produces solutions that no single individual could have invented on their own). We show that the use of unidimensional metrics of cumulativeness drastically curtail the variation that may be observed, which raises specific issues in the interpretation of the experimental evidence. We suggest several solutions to these mismatches (learning times, task complexity and variation) and develop the use of design spaces in experimentally investigating old and new questions about cumulative culture.
A leading idea of cultural evolutionary theory is that for human cultures to undergo evolutionary change, cultural transmission must generally serve as a high-fidelity copying process. In analogy to genetic inheritance, the high-fidelity of human cultural transmission would act as a safeguard against the transformation and loss of cultural information, thus ensuring both the stability and longevity of cultural traditions. Cultural fidelity would also serve as the key difference-maker between human cumulative cultures and non-human non-cumulative traditions, explaining why only us humans, with our uniquely high-fidelity transmission capabilities, are capable of evolving and sustaining complex traditions. But what does it mean for cultural transmission to be more or less faithful? This paper has two objectives. The first is to clarify the meaning and uses of the concept of cultural fidelity and to evaluate their explanatory import. I argue that cultural evolutionists use several fidelity concepts (episodic, propensity, and generalized fidelity), concepts that I will define and clarify. The second objective is to challenge the explanatory significance of a general notion of fidelity (generalized fidelity) as being both explanatorily meaningful and operationalizable. I conclude that if fidelity is to serve as an explanation of the key differences between human cumulative cultures and non-human non-cumulative traditions, then the concept will have to be redesigned and rely on different assumptions.
Herein, we present the first example of a benzimidazolium-based artificial transmembrane chloride transporter and a synthetic calcium ionophore that can regulate intracellular calcium concentrations in bacteria.
Among the various new challenges of chemical processes in water, research on stable, highly active, and recyclable catalysts is a prosperous field. We present here a palladium−NHC catalyst that was synthesized with good yields through a series of simple synthetic steps. This organometallic species was used as a heterogeneous catalyst in low loadings for Suzuki−Miyaura coupling in neat water, under mild conditions. Reaction conditions were optimized for a simple, green, and support-free procedure, without using any phase transfer agent. The catalyst shows excellent reactivity in short times toward different substrates and a very good recyclability.
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