Scientists are finally coming closer to solving one of humanity’s oldest mysteries: why we dream. In a comprehensive study released this week by the International Institute of Sleep Science (IISS) in Geneva, researchers from Europe, the United States, and Japan revealed new findings about when dreams occur, how they are formed, and what they mean for emotional and cognitive health.
The multi-country research, conducted between 2022 and 2025 across sleep laboratories in Geneva, Berlin, Boston, and Tokyo, involved more than 600 volunteers who were monitored using advanced neural imaging, REM eye-tracking, and early-stage AI brain-to-text decoding systems. The data collected from these controlled lab experiments has produced the most detailed scientific map of dream activity to date.
According to the findings, dreams primarily begin during the REM (Rapid Eye Movement) stage of sleep, which usually starts about an hour after a person falls asleep. This stage shows brain activity nearly as intense as wakefulness, especially in the visual cortex and memory-processing regions, which explains why REM dreams are vivid and emotional.
However, the study also confirms that dreaming happens during non-REM stages, particularly in lighter sleep phases (N1 and N2), though these dreams tend to be less visual and more fragmented. Deep sleep (N3) remains the least dream-filled phase. Scientists have long debated why humans dream, but the new evidence strengthens four major theories: emotional healing, memory consolidation, creativity enhancement, and neurological maintenance.
Brain scans show the amygdala becomes highly active during REM sleep, supporting the idea that dreaming helps us regulate stress and emotions. Meanwhile, the hippocampus replays and reorganizes memories, stitching them into symbolic narratives that help the brain decide what to retain. Experiments also recorded “creative recombination,” where the dreaming brain merges unrelated ideas, hinting at why solutions often appear in dreams. Other researchers argue that dreams act like a nightly “software update,” strengthening key neural pathways.
The process of dreaming itself follows a remarkable sequence. As the body falls asleep, it gradually shuts down external sensory input. With the outside world muted, the brain generates its own imagery, sounds, and emotions. Memory, imagination, and emotional centers begin to communicate intensely, forming story-like sequences even though the prefrontal cortex, the logical control center, is less active. This explains why dreams feel vivid yet irrational. Scientists note that if a person is awakened during REM sleep, they recall the dream about 80 percent of the time; in contrast, awakening from deep sleep results in less than 10 percent recall, contributing to the common feeling that dreams “disappear.”
One of the most groundbreaking aspects of the study involves dream decoding. Using neural-visual AI models developed in Berlin, researchers managed to reconstruct blurry, color-based outlines of images participants reported seeing in their dreams. While still in early development, the technology represents the first step toward partially recording dreams. Another Boston-based experiment focused on lucid dreamers, people aware that they are dreaming. Scientists communicated with them using pre-agreed eye-movement signals. Astoundingly, some participants solved math problems inside their dreams and responded correctly with their eyes, marking the first successful two-way communication between the dreaming and waking world.
These developments could have far-reaching consequences. Mental health professionals are already exploring how dream-tracking technologies might help treat PTSD, anxiety, or recurring nightmares by allowing therapists to identify emotional patterns more precisely. Creative industries may also benefit, as artists and writers could one day transfer dream imagery into digital form. Although the mystery of dreams is not fully unlocked, the latest research proves that our nighttime world is far more structured, purposeful, and scientifically revealing than previously understood. What once felt like random, fleeting illusions may soon become a powerful window into the subconscious mind.
