Did technology transfer more rapidly East–West than North–South?

We offer evidence of the role of continental orientation in the historical diffusion of technologies. Diamond (1997) argued that technologies spread more slowly North–South (N–S) than East–West (E–W) for two reasons. First, it was relatively costly for individuals to transport innovations when experiencing N–S variations in climate. Second, some innovations (e.g., selectively bred seeds) would have been less likely to survive N–S movements. Continents with E–W orientation, then, were characterized by less costly and/or more successful sharing of technologies. We employ Comin’s et al. (2010) data on ancient and early modern levels of technology adoption in a spatial econometric analysis. Historical levels of technology adoption in a (present-day) country are related to its lagged level as well as those of its neighbors. The E–W spatial correlations are generally larger, more likely to be positive, and more likely to be statistically significant. While acknowledging that the difference between E–W and N–S effects is not significant in every estimation, taken together the results offer compelling support for the Diamond hypothesis.