摘要：Many information structures generate correlated rather than mutually in-dependent signals, the news media being a prime example. This paper showsexperimentally that in such contexts many people neglect these correlationsin the updating process and treat correlated information as independent. Inconsequence, people’s beliefs are excessively sensitive to well-connected infor-mation sources, implying a pattern of “overshooting” beliefs. Additionally,in an experimental asset market, correlation neglect not only drives overop-timism and overpessimism at the individual level, but also affects aggregateoutcomes in a systematic manner. In particular, the excessive confidenceswings caused by correlated signals give rise to predictable price bubbles andcrashes. These findings are reminiscent of popular narratives according towhich aggregate booms and busts might be driven by the spread of “stories”.Our results also lend direct support to recent models of boundedly rationalsocial learning.
