We find evidence of selective exposure to confirmatory information among 400,000 users on the investor social network StockTwits. Self-described bulls are five times more likely to follow a user with a bullish view of the same stock than are self-described bears. Consequently, bulls see 62 more bullish messages and 24 fewer bearish messages than bears do over the same 50-day period. These “echo chambers” exist even among professional investors and are strongest for investors who trade on their beliefs. Finally, beliefs formed in echo chambers are associated with lower ex post returns, more siloing of information, and more trading volume.

中文翻译：

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回声室

我们在投资者社交网络 StockTwits 上的 400,000 名用户中发现了选择性接触确认信息的证据。自称多头的人跟随对同一股票看涨的用户的可能性是自称空头的人的五倍。因此，在相同的 50 天内，多头看到的看涨消息比空头多 62 条，看跌消息少 24 条。这些“回音室”甚至存在于专业投资者中，并且对于根据自己的信念进行交易的投资者来说最为强大。最后，在回声室中形成的信念与较低的事后回报、更多的信息孤岛和更多的交易量有关。