Memory, innovation and vertical learning

One of the most controversial and actively debated questions about both human and non-human animal culture concerns its relationship with adaptation – under what circumstances might we expect culture, and the ability to learn socially from others, to be beneficial, and favored by natural selection? Existing theory posits that the benefit of social learning depends on the rate at which the environment changes, and recent work has shown that this relationship is mediated by how much information an individual can retain over time - by memory. Based on extensive ethnographic research, vertical learning—social learning from parent to offspring—appears to be an extremely salient and important type of social learning. Here we develop large-scale agent-based simulation models to investigate the evolutionary relationship between vertical social learning in particular and the memory and retention of cultural information.We show that the benefit of vertical learning depends on how quickly those information is forgotten and on the exact way in which individuals innovate. This work points to the importance of a complex interplay between the size of cultural repertoires, the benefits of cultural preservation, changing selective environments, and the mechanism of innovation - none of which can be fully understood in isolation.Author summary: One of the most debated questions about both human and animal culture is when it is beneficial and supported by evolution? Existing theory posits that this depends on the speed of environmental change, and new research shows that memory, or how much information someone can hold, plays a big role, too. Ethnographic studies indicate that learning from parents (known as vertical learning) is a particularly important form of cultural learning. In this study, we use large-scale simulations to explore the interplay between vertical learning and memory in the retention of cultural knowledge over time. Our findings show that the advantage of vertical learning depends on how quickly individuals forget information and how they come up with new ideas through innovation. This highlights the complex interaction between the environment, the amount of cultural knowledge both held by the individual and transmitted across generations, and the process of innovation.