Different phases of sleep assist in daily functioning. As adults, we spend an average of two hours (about 25 percent of our total sleep time) each night dreaming (p. 135). By late adulthood, humans will spend nearly six years of their lives dreaming. Dreaming, an interesting facet of sleep, is studied heavily. Interestingly, if an individual is awakened during their REM sleep cycles and prohibited from dreaming for a prolonged period of time they will experience what is referred to as a dream rebound. Dream rebounds usually are comprised of increased dream activity, with individuals sometimes reporting more vivid and enhanced dream content. A study published in the Journal of Personality and Social Psychology revealed that adults in diverse cultures believe that dreams are meaningful and, often, that they contain important hidden truths. Theorists also have long been interested in why we dream, as well as in the content of our dreams. As you begin this activity, reflect on your own beliefs about dreams.