Making matters worse is that research shows being “smart” actually makes certain behavioral biases worse: The smarter you are, the better you are at constructing a narrative that supports your held belief.
Duke cites the research of Richard West, Russell Meserve and Keith Stanovich, who tested the blind-spot bias. They found we are much better at recognizing biased reasoning in others but are blind to recognizing it in ourselves.
Surprisingly, at least to me, West, Meserve and Stanovich also found that the better you were with numbers, the worse the bias—the better you are with numbers, the better you are at spinning those numbers to suit your narrative. Quoting Duke: “Our capacity for self-deception knows no boundaries.” So, what does this have to do with investing?
Invest By Playing The Odds
When it comes to investing, there are no clear crystal balls. Just as in poker, the best we can do is put the odds in our favor and invest (bet) accordingly.
As I recently discussed, using factor data from Dimensional Fund Advisors from 2007 through 2017, the value premium (the annual average difference in returns between value stocks and growth stocks) was -2.3%. Unfortunately, resulting, hindsight bias and recency bias led many to conclude it was a mistake to invest in, or overweight, value stocks.
Another way to look at the situation is that, over 10-year periods since 1927, value stocks outperformed growth stocks 86% of the time—the same percentage as in the aforementioned poker hand. The value premium’s now-decade-long underperformance was not unexpected, in the sense that in 14% of the alternative universes that might have shown up, we expected value stocks to underperform.
Similarly, again using Dimensional Fund Advisors data, the market-beta premium has been negative (U.S. stocks underperformed riskless one-month Treasury bills) in 9% of the 10-year periods since 1927.
In other words, investing is risky. To be successful, you must accept that fact there will be periods, even very long ones, when the right strategy leads to poor outcomes. Even at 20-year horizons, the market beta premium has been negative 3% of the time. That is why Warren Buffett has said investing is simple, but not easy. It takes discipline to earn risk premiums.
One of the hardest things for investors to do is to stay disciplined when their strategy delivers poor results. It certainly is possible that the strategy was wrong. To determine if that is the case, look to see if the assumptions behind the strategy were correct. Seek the truth, whether it aligns with your beliefs or not. For investors, the truth lies in the data. When your theory isn’t supported by the data, throw out your theory.
While it’s certainly not an investment book, investors can learn many lessons from Duke’s “Thinking in Bets.”
Larry Swedroe is the director of research for The BAM Alliance, a community of more than 140 independent registered investment advisors throughout the country.