Not everyone in the world requires the same amount of living space. The amount of space a person needs around him is a cultural(文化的) difference, not an economic (经济的) one. Knowing your own psychological (心理的)space needs is important because they strongly affect your choices, including for example, the number of bedrooms in the home. If you were brought up in a two-child family and both you and your sister or brother had your own bedrooms, the chances are, if you have two children or more, that you also will offer separate bedrooms for them. In America, for example, they train people to want to have their own rooms by giving them their own rooms when they are babies. This is very rare in the world. In many other countries, the baby sleeps in the same bed with his parents or in bed near them. The space in the home also shows a lot about psychological space needs. Some families gather closer to each other and the size of their house has nothing to do with it. Others have separate little comers where family members go to be alone. Although it is true that psychological space needs are not decided by economic reasons, they sometimes have to be changed a little because of economic pressures. It is almost impossible, however, to completely change your psychological space needs. The first sentence in Paragraph 1 means ______.