My "Intelligent Investor" column this weekend discusses new research on what psychologists call "shared attention"—the state of paying heed to an object or event at the same time your peers are also focusing on it. Believing that other people like you are paying attention to the same thing you are can make you more likely to remember it, to take action on it and to experience more intense emotions about it, the research finds.

As a result, I advised, the investors you follow may be as important to your financial results as the investments you own. If the people you pay attention to are excitable and impulsive, they may overreact to market moves—and you may follow suit, under the spell of shared attention. No wonder Warren Buffett so often urges that you should "hang out with people who are better than you are."

In my column, I encouraged investors to socialize "only with investors who are calm and methodical." Here's a small selection of websites, blogs and Twitter feeds that I think pass that test. It is far from complete; there are other sites I like for other reasons, but the sources I've listed here all encourage investors to ignore the markets' momentary twitches and spasms and, instead, to focus on the long term. I've listed them alphabetically. Please suggest your own favorites in the comments.

Abnormal Returns and @abnormalreturns

Edited by the indefatigable Tadas Viskanta, this "forecast-free" blog and Twitter feed is one of the best ways to put short-term events in long-term perspective. The site links each day to a carefully curated selection of the best and most analytical posts anywhere online about investing.