Published as:

Carrignon S, Brughmans T, Romanowska I. (2020) Tableware trade in the Roman East: Exploring cultural and economic transmission with agent-based modelling and approximate Bayesian computation. PLoS One. 2020;15: e0240414. doi:10.1371/journal.pone.0240414

Carrignon S, Brughmans T, Romanowska I. (2022) Copying of economic strategies in eastern Mediterranean inter-regional tableware trade. In: Brughmans T, Wilson A, editors. Simulating Roman Economies. Theories, Methods and Computational Models. Oxford: Oxford University Press. pp. 144–166.

In short

What explains the much wider distribution of Eastern Sigillata A (ESA) tableware over a period of centuries? Can this pattern emerge as a result of historical contingency (a lock-in effect caused by it being available before other products)? Is preference for this product necessary to explain it?
What explains the decline of ESA? Its competition with Italian Sigillata (ITS) and other eastern products?
What is the impact of the introduction of ITS on the distribution of eastern tablewares? Can direct competition alone explain the changes in distribution? Is preference for a new product a necessary factor?

From Carrignon et al. 2020, Fig. 2. Geographical distribution of the 178 eastern Mediterranean sites from the ICRATES database. Each point represents one archaeological site. Presumed production regions of ESA, ESB, ESC, ESD are labeled. Map created using data from Natural Earth (http://www.naturalearthdata.com/)

A bit longer

The availability of reliable commercial information is considered a key feature of inter-regional trade if the Roman economy was highly integrated. However, the extent to which archaeological and historical sources of inter-regional trade reflect the degree of economic integration is still not fully understood, a question which lies at the heart of current debates in Roman Studies. Ceramic tableware offers one of the only comparable and quantifiable sources of information for Roman inter-regional trade over centuries-long time periods. The distribution patterns and stylistic features of tablewares from the East Mediterranean dated between 200 BC and AD 300 suggest a competitive market where buying decisions might have been influenced by access to reliable commercial information. We contribute to this debate by representing three competing hypotheses in an agent-based model: success-biased social learning of tableware buying strategies (requiring access to reliable commercial information from all traders), unbiased social learning (requiring limited access), and independent learning (requiring no access). We use approximate Bayesian computation (ABC) to evaluate which hypothesis best describes archaeologically observed tableware distribution patterns. Our results revealed success-bias is not a viable theory and we demonstrate instead that local innovation (independent learning) is a plausible driving factor in inter-regional tableware trade. We also suggest that tableware distribution should instead be explored as a small component of long-distance trade cargoes dominated by foodstuffs, metals, and building materials.

Acknowledgements

TB received funding from The Leverhulme Trust ECF 2016-197 SC and IR received funding from the EPNet Project ERC-2013-ADG 340828