When we sleep, especially during the rapid-eye movement (REM) phase, our brains become highly active, almost as if we were awake. This heightened activity is what gives rise to dreams—vivid, often strange experiences that can feel incredibly real while they unfold. But how does the brain end up confusing these fictional dream worlds with reality? To understand this, we need to explore the complex interplay of brain regions, neural signals, and the way our minds try to make sense of fragmented information during sleep.
Dreams don’t just consist of random images flashing by; they usually form a narrative, a story that our brain constructs. This storytelling aspect is crucial because it shows how the brain tries to impose order on what is essentially chaotic and incomplete data. During REM sleep, many parts of the brain that are active when we’re awake become only partially active or behave differently. For example, the sensory areas responsible for processing real-world input are mostly shut down since we aren’t actually seeing or hearing anything outside. Yet, the brain’s visual centers still fire, creating vivid images internally. This means the brain is generating its own “sensory” experiences without any external input.
At the same time, the brain’s “interpreter” — a concept referring to the left hemisphere’s tendency to create explanations and stories — kicks into gear. It takes the scattered, random neural signals produced during sleep and tries to weave them into a coherent narrative. This interpreter doesn’t have access to the usual sensory checks and balances that keep us grounded in reality when we’re awake. Instead, it works with incomplete, distorted, or even nonsensical information. The result is a dream story that can seem perfectly logical while we’re experiencing it, even though it might be bizarre or impossible when we wake up.
One reason the brain confuses fiction with reality during sleep is that the usual mechanisms that help us distinguish between what’s real and what’s imagined are less active or altered. For example, the prefrontal cortex, which is responsible for critical thinking, judgment, and self-awareness, shows reduced activity during REM sleep. This reduction means we’re less likely to question the strange events happening in our dreams or realize that we’re dreaming at all. Without this critical oversight, the brain accepts the dream’s narrative as real, at least temporarily.
Moreover, the emotional centers of the brain, like the amygdala, are highly active during REM sleep. This heightened emotional activity can make dream experiences feel intense and convincing. Emotions add a layer of realism to dreams, making the fictional scenarios feel personally significant or urgent. This emotional charge can further blur the line between what’s real and what’s imagined.
Another factor is memory processing. During sleep, the brain is busy consolidating memories, sorting through the day’s experiences, and integrating new information. This process can mix fragments of real memories with invented or distorted elements, creating dream content that feels familiar yet altered. Because these dream fragments often come from our own experiences, the brain’s narrative interpreter can easily stitch them into stories that feel plausible, even if they never actually happened.
The sensory experience in dreams is also convincing because the brain’s visual and auditory areas are activated in ways similar to waking perception. The brain essentially “replays” or simulates sensory input internally. Since there is no external sensory input to contradict these internal simulations, the brain accepts them as real. This internal simulation is why dreams can be so immersive and why we can sometimes wake up feeling disoriented, unsure if what we experienced was real or just a dream.
In some cases, the brain’s confusion between fiction and reality during sleep can lead to phenomena like false awakenings, where a person dreams of waking up and going about their day, only to actually wake up later. This happens because the brain’s narrative system creates a convincing scenario that mimics reality so closely that the dreamer believes it is real until they truly wake.
Lucid dreaming is an interesting exception to this confusion
