Because if your mind tries to convince you you're incapable of something, and you believe it, then like those two toddlers, you'll begin to feel helpless and you'll stop trying too soon, or you won't even try at all.
Porque se a mente trata de convencelos de que son incapaces de algo e o cren, entón, como aqueles dous cativos, comezarán a sentirse impotentes e pronto deixarán de intentalo tamén, ou nin sequera probarán en absoluto.