It assists us in associating to other memories long forgotten. Dream symbols are different for people of separate backgrounds and beliefs. This is because they put their subjective worlds together in distinct ways. They use different ideas. This causes them to associate memories and ideas together in unique ways.
Many people confine their associations to the physical world.
This limits their associations and hampers dream recall. When you are remembering people and events learn to let your associations delve in and out of your dream memories. The reason association is such a powerful tool in dream interpretation is that when traveling in the dream world you go from one situation to another through association. It is in many ways the dream world's equivalent of physical time. Dreaming is much like telling someone a story, except while dreaming you live the story.