"Lucid dreamers report being able to freely remember the circumstances of waking life, to think clearly, and to act deliberately upon reflection, all while experiencing a dream world that seems vividly real" (LaBerge, 1990). In lucid dreaming, people become conscious enough to realize what they are dreaming, and therefore can change the dream they are having. A theory widely accepted by many researchers, is "That lucid dreams are not typical parts of the dreaming thought, but rather brief arousals" (LaBerge, 1990). The researchers came up with the fact that the arousals were frequently happening during REM sleep and this became the platform for lucid dreams. In the late 1970's, evidence started showing up that lucid dreams occur during REM sleep. To test this hypothesis out, 4 scientists by the names of: LaBerge, Nagel, Dement and Zarcone got together and set up an experiment. In this experiment, the scientists had to use some sort of signal or response to determine the exact time the lucid dream was occurring. In the experiment, the scientists used five subjects and studied each from two to twenty nights, depending upon how long the scientists thought they needed. All in all, they studied the subjects a total of 34 nights and came up with a total of 35 lucid dreams from various stages of sleep. Of the 35 lucid dreams, 32 occurred during REM sleep, and the other three took place during other stages of the sleep cycle. "A later analysis extending these data with two additional subjects and 20 more lucid dreams produced identical results" (LaBerge, 1990). This led LaBerge and the three other scientists to believe that lucid dreaming usually occurs during REM sleep. Many other researchers were also studying lucid dreaming and the time of their occurrence. Two such researchers, named Keith Hearne and Alan Worsley, designed a study of lucid dreaming. In their experiment, the subject spent 50 non-continuous nights in the Hull University sleep lab while the experimenter monitored the polygraph.