If there's one thing we've learned over the last few decades, it's that humans are hardwired to be horrible investors. Are there exceptions? Of course. But the vast majority of us fall, the general rule applies: Greed causes us to buy when stocks are high, and fear induces us to sell when stocks are low.

In the video below, Motley Fool contributor John Maxfield outlines how investors can circumvent these emotional weaknesses by using two broad-market, exchange-traded funds: the Vanguard Total Stock Market Index (NYSEMKT:VTI), which tracks virtually the entire universe of U.S. stocks, and the SPDR S&P 500 (NYSEMKT:SPY), which tracks the S&P 500 (SNPINDEX:^GSPC).

John Maxfield has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.