Communication and the Emergence of a Unidimensional World

Abstract While individuals hold, exchange, and update opinions over multiple issues, these opinions are often correlated, and a unidimensional spectrum is enough to summarize them. But when should one expect opinions to be unidimensional? And how important is the underlying structure of communication? Our experimental results validate the crisp predictions by DeMarzo, Vayanos, and Zwiebel (2003) when individuals update their opinions on a fixed network, always trusting the same neighbors, and confirm the importance of the communication structure in predicting whether individuals hold relatively moderate or extreme opinions. We also provide a theoretical result, simulation results, and experimental evidence suggesting that unidimensionality may arise even when individuals’ networks vary over time.