Abstract:

Physicist Max Planck famously said that “A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die”. This is basically a theory of human cultural change, one rooted primarily in the mechanisms of differential recruitment, inheritance and demography. If the Planck Principle (as it has come to be known) is a key explanatory force, it has major implications for the study of cultural evolution, which has instead traditionally focused on the role of social and individual learning (as people ‘see the light’). Although there have been several projects focusing on the role of demographic turnover in cultural evolution, evidence to date has been mixed and equivocal. A key theoretical limitation has been the lack of a principled way to compare the relative strength of different forces of cultural evolution.

To solve this problem, we adapt the method of *evolutionary decomposition* pioneered in mathematical demography, which applies Price’s Theorem to trajectories of phenotypic change. Using a novel derivation of this approach tailored to historical archives of creative human culture, we can measure (for the first time) the relatively explanatory strength of three categories of force in cultural evolution, namely, the entrances of new cohorts, the process of attrition, and the “changiness” of individuals over the course of their creative careers. Taking this to a variety of high-resolution longitudinal datasets, including song lyrics, board game strategies, and stylistic themes in European literature and musical compositions, we find strong evidence for the importance of population turnover and the entrance of new cohorts with splashy, disruptive ideas. Rather than Planck’s formulation of cultural change “one funeral at a time”, however, we find instead many circumstances where cultural change occurs “one birth at a time”. We also find systematic differences in the relative strength of these three categories of force, with some systems being driven by social learning and strategic adoption dynamics consistent with the canonical models of social learning, while others being mostly characterized by the slower process of demographic replacement. Our results demonstrate the value of an expanded, force-centric approach to studying long-term cultural change.

Zoom link:

https://ucla.zoom.us/j/94308730584?pwd=0YGsaJFEdLd5cMsOhTh465nwJubz9o.1

Meeting ID: 943 0873 0584

Passcode: 308291