请根据短文的内容，回答题。 What Is a Dream? For centuries, people have wondered about the strange things that they dream about. Some psychologists say that this nighttime activity of the mind has no special meaning. Others, however,think that dreams are an important part of our lives. In fact, many experts believe that dreams can tell us about a person&39;s mind and emotions. Before modern times, many people thought that dreams contained messages from God. It was only in the twentieth century that people started to study dreams in a scientific way. The Austrian psychologist, Sigmund Freud, was probably the first person to study dreams scientifically. In his famous book, The Interpretation of Dreams (1900), Freud wrote that dreams are an expression of a person&39;s wishes. He believed that dreams allow people to express the feelings, thoughts, and fears that they are afraid to express in real life. The Swiss psychiatrist Carl Jung was once a student of Freud&39;s. Jung, however, had a different idea about dreams. Jung believed that the purpose of a dream was to communicate a message to the dreamer. He thought people could learn more about themselves by thinking about their dreams. For example, people who dream about falling may learn that they have too high an opinion of themselves. On the other hand, people who dream about being heroes may learn that they think too little of themselves. Modern-day psychologists continue to develop theories about dreams. For example, psychologist William Domhoff from the University of California, Santa Cruz, believes that dreams are tightly linked to a person&39;s daily life, thoughts, and behavior. A criminal, for example, might dream about crime. Domhoff believes that there is a connection between dreams and age. His research shows that children do not dream as much as adults. According to Domhoff, dreaming is a mental skill that needs time to develop. He has also found a link between dreams and gender. His studies show that the dreams of men and women are different. For example, the people in men&39;s dreams are often other men, and the dreams often involve fighting. This is not true of women&39;s dreams. Domhoff found this gender difference in the dreams of people from 11 cultures around the world, including both modern and traditional ones. Can dreams help us understand ourselves? Psychologists continue to try to answer this question in different ways. However, one thing they agree on this: If you dream that something terrible is going to occur, you shouldn&39;t panic. The dream may have meaning, but it does not mean that some terrible event will actually take place. It&39;s important to remember that the world of dreams is not the real world. Not everyone agrees that dreams are meaningful. 查看材料