The purpose of this research is to investigate whether sensory cues—such as specific sounds, light, and gentle vibrations delivered via a smartphone—can help individuals experience lucid dreams (the state of being aware that you are dreaming while the dream is happening). How to participate: - Duration: 8 nights total. - Nightly routine: 20 mins of pre-sleep app training each night. - Morning routine: A brief survey every morning. - Eligibility criteria: You must sleep alone during the nights you participate (due to the sound/light cues), be 18+, and have no implanted medical devices.