What is your favorite color? Do you like yellow, orange or red? If you do, you must be an optimist (乐观者), a leader, an active person. Do you prefer grays and blues? Then you are probably quiet, shy and you would rather follow than lead. If you love green, you are strong-minded and determined. At least this is what psychologists (心理学家) tell us. They have been seriously studying the meaning of color preference (爱好), and the effect that colors have on human beings. They tell us that we don't choose our favorite color as we grow up. If you happen to love brown, you did so as soon as you opened your eyes, or at least as soon as you could see clearly. A yellow room makes us feel more cheerful and more comfortable than a dark green one. On the other hand, black is depressing. Light and bright colors make people not only happier but more active. It is a fact that factory workers work better, harder, and have fewer accidents when their machines are painted orange rather than black or dark gray. Remember that you will know your friends and your enemies better when you find out what colors they like and dislike. And don't forget that anyone can guess a lot about your character when you choose a piece of handkerchief. According to this passage,______.