The popularity spectrum applied to a cross-cultural question

Area of Science:

• Archaeology
• Cultural Evolution
• Social Network Analysis

Background:

• Understanding cultural transmission is key to explaining cross-cultural similarities and differences.
• Distinguishing between vertical (parent-to-offspring) and horizontal (between peers) transmission is challenging.

Purpose of the Study:

• To introduce a novel analytical framework for quantifying horizontal transmission's contribution to cultural similarity.
• To apply this framework to archaeological and ethnographic data.

Main Methods:

• Development of analytical and simulation models based on popularity spectra.
• Fitting models to archaeological and ethnographic datasets using Bayesian Markov Chain Monte Carlo (MCMC) methods.
• Validation using individual-based models simulating different population structures.

Main Results:

• Popularity spectra are sensitive indicators of horizontal transmission.
• Evidence suggests stronger horizontal transmission in oceanic cultural datasets compared to continental ones.
• Dataset structure (e.g., island vs. lattice) can influence estimations of vertical transmission rates.

Conclusions:

• The developed method effectively identifies and quantifies horizontal cultural transmission.
• Horizontal transmission plays a significant role in shaping cultural similarity, particularly in geographically dispersed (oceanic) groups.
• Further research is needed to clarify the distinction between borrowing of functional versus stylistic traits.