This research explores the effects of culture on technological diffusion and economic development. It shows that culture's direct effects on development and barrier effects to technological diffusion are, in general, observationally equivalent. In particular, using a large set of cultural measures, it establishes empirically that pairwise differences in contemporary development are associated with pairwise cultural differences relative to the technological frontier, only in cases where observational equivalence holds. Additionally, it establishes that differences in cultural traits that are correlated with genetic and linguistic distances are statistically and economically significantly correlated with differences in economic development....