1 .		People who wake up in the middle of the night often are considered insomniacs. They may spend hundreds of dollars on therapy, sleeping pills, and other medications, which can replace one problem with another. New research, however, suggests that our ideal seven or eight-hour sleep pattern is a relatively recent, western phenomenon. Psychiatrist Thomas A. Wehr has found that the presence of artificial light affects our sleeping patterns. Wehr conducted experiments in which he deprived his test subjects of artificial light. The test subjects' sleep patterns changed. Separated by a period in which they were awake, but relaxed, Wehr's test subjects started sleeping in two shifts, of approximately four hours' duration. Wehr theorizes that this period of quietude offered an opportunity to meditate and to ponder dreams, not available to those of us who sleep through the night. Wehr's research illuminates the work of historian Roger Ekirch, who explains that sleeping straight through the night became a cultural norm in the nineteenth century only. Ekrich, in fact, tells us that the two shifts were known commonly as the "first sleep" and the "second sleep." Today's "insomniacs" may learn to appreciate their "problem," if they consider this research.   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.