What is your favorite color? Do you like yellow, orange or red? If you do, you must be an optimist, a leader or an active person who enjoys life, people and excitement. Do you prefer grays and blues.'? Then you are probable quiet, shy and you would rather follow than lead. If you love green, you are strong-mined and determined. At least this is what psychologists tell us, and they should know, because they have been seriously studying the meaning of color preference, and the effect that colors have on human being's emotions. 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. Light and bright colors make people not only happier but also more active. It is a fact that factory workers work better when their machines are painted orange rather than black or dark gray. Remember, then, that if you feel low, you can always brighten your day or your life with a new shirt or a few colorful things. Remember also that you will know your friends or your enemies better when you find out what colors they like and dislike. And don't forget that anyone can guess about your character when you choose a piece of handkerchief. The author believes in the passage that ______.