Can You Measure Dream Meanings?

In the 19 sixties and seventies, a psychologist named David folks studied dreams in children. He found that pre schoolers had very simple dreams about themselves or animals but as they got older, their dreams involved more people and the stories got more complicated. But recently, as some researches have shown, if you record dreams, not in the laboratory, but if you go to the children's home to record the dreams, they are richer. That's really interesting,. But why would that be?