Investors are prone to two opposing but equally debilitating fears: the fear of missing out when times are good, and the fear of loss when markets are volatile. These two fears have a zero-sum relationship with rational decisions. The more you are dominated by these fears, the less rational you are.

So what can we do, as investors, to move toward maximum rationality? Here’s one piece of advice: Turn off the TV.

We rarely turn on business TV in our office. Stock market movements throughout the day are completely random. The same actors that are influencing the up-and-down ticks of individual stocks–actors whose goals and time horizons may have nothing in common with yours–are driving market movements. I feel for TV producers who must provide a continuous narrative to explain this randomness.

Business TV presents additional dangers to your rationality: It reprograms you to think about the stock market as a game. In encouraging you to play that game, it puts you at risk of nullifying all the research you’ve done, as you let your time horizon dwindle from years to minutes.

It also threatens to strip from you the humility that is so needed in investing. Business TV guests who provide their opinions on stocks have to project an image of infallibility (the opposite of humility). Again, I sympathize with them – they are there to market themselves and their business, and thus they must project the image that they have an IQ of 200, holding forth on every possible topic.

You are never going to hear from them the words that are the essence of investing: “I don’t know.” Being unable to admit uncertainty is dangerous, because it may cause you to stop thinking about investing in terms of probabilities. If you start thinking that the future has only one path, you may ignore other paths and thus other risks in your portfolio construction. If you tell yourself that you’re an expert on every company, then your circle of competence has no boundaries and your overconfidence may take you to places (and into investments) where you have no place being.

Also, since “I don’t know” is not part of their vocabulary, business TV guests will confidently answer questions that should never be asked, such as “What will the economy and stock market do next?” If you have been investing long enough, it is hard not to develop opinions (hunches) about what the stock market and economy will do next. However, good money managers work diligently to extinguish these hunches from their investment process, because those hunches lack repeatability.

(Read: “Stocks Have Gotten 17% More Expensive in Two Months. Here’s Why.”)

If you get the next leg of the stock market or economy right, that’s just dumb luck – nothing more and nothing less. Economic and stock market behavior, especially in the short term, are very random. God forbid your recent forecasting success goes to your head, because your ability to predict what will come next is not much different from your predicting the next card to be turned up in blackjack.

Be an investor, not a forecaster

My colleagues and I used to identify with our self-proclaimed “I am a long-term investor” brethren. However, over time this phrase has morphed to mean “I am a buy-and-hold (and never sell) investor.”

Also, the term long-term investor, in our view, is a bit redundant, since there is no such thing as short-term investing in the stock market. If you are investing in stocks, then your time horizon should automatically be long-term; otherwise you are just a trader deceiving yourself into thinking that you’re an investor. However, investing is not just about the holding time horizon. The analytical time horizon is just as important.

To us, being investors means having an attitude with which we look at stocks and process information. We buy businesses that happen to be listed on public exchanges, but our attitude toward them would not be much different if they were private. We view all news, be it quarterly guidance (whether it’s “great” or “disappointing”), upgrades or downgrades by analysts, or any headline crossing our screens in the context of one question: How does this impact the value of the business?

This perspective is liberating, because you start to process the news flow very differently. You develop a resistance to the distractions of the everyday news dump. Quarterly earnings stop being about “beating” or “missing” guidance. Ultimately, this simple question, “How does it impact the value of the business?” filters out 90% of the noise and puts us on a solid investment footing.

Vitaliy Katsenelson, CFA, is the CEO at Investment Management Associates, Inc. He writes about the markets at ContrarianEdge.com, and is the author of The Little Book of Sideways Markets (Wiley).