Which of the following sleep stages is most associated with vivid dreams?

REM sleep, or Rapid Eye Movement sleep, is the stage of sleep most strongly associated with vivid dreaming. During REM sleep, the brain exhibits heightened activity similar to that of waking hours, and this heightened brain activity is believed to facilitate more complex and vivid dreams. The characteristic rapid eye movements and irregular brain waves seen in this stage distinguish it from other stages of sleep.

In contrast, other stages of sleep such as Stage 1, Stage 2, and Stage 3 largely involve lighter sleep and deeper restorative processes, where dreams may be less vivid or even not remembered at all. Stage 1 is a transition period between wakefulness and sleep, Stage 2 is characterized by sleep spindles and K-complexes which indicate deeper sleep, and Stage 3 (also known as slow-wave sleep) involves very deep sleep that is crucial for physical recovery and consolidation of memories, without the intense dream experiences associated with REM.