What's the purpose of dreaming?
We all dream — but why? As with many mysteries of the mind, science doesn't have one neat answer.
'You'll get as many answers to the question 'What is the purpose of dreaming?' as there are dream psychologists,' says Deirdre Barrett, dream researcher at Harvard University and author of The Committee of Sleep.
According to Austrian neurologist and founder of psychoanalysis Sigmund Freud, dreams offered vital clues to unresolved conflicts buried deep within our psyche. But Freud's theory, introduced in his 1899 book The Interpretation of Dreams, sparked plenty of controversy. Critics argued that his dream interpretations were overly focused on sex, highly subjective, and impossible to verify—two analysts might offer entirely different readings of the same dream, with no objective way to know who was right.
In the decades since Freud, other scientists have offered alternative explanations for why we dream. One of the most prominent is the threat simulation theory, proposed by Finnish neuroscientist and psychologist Antti Revonsuo in 2000. According to this view, dreaming is an ancient biological defense mechanism. By simulating dangerous situations, our brains rehearse the skills needed to recognize and avoid threats—a kind of virtual reality training ground for survival. A 2005 study lent support to this theory by examining the dreams of Kurdish children exposed to war and trauma. Compared to non-traumatized Finnish children, these children reported more frequent dreams filled with severe threats, suggesting that their minds were practicing how to cope with danger.
But even the threat simulation theory is debated. A 2008 study comparing residents of high-crime areas in South Africa to those in low-crime parts of Wales found that South African participants, despite facing more real-world threats, actually reported fewer threatening dreams than their Welsh counterparts. This result challenges the idea that the brain uses dreams to simulate danger when exposed to trauma.
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Another theory suggests that dreams are simply a side effect of memory consolidation—the brain's way of replaying and reinforcing new memories while we sleep. As the brain's hippocampus and neocortex work together to file away fresh information, they may also blend it with older memories, creating the often strange mashups we experience as dreams.
Dreams may also help us process and manage emotions, especially negative ones, according to the emotion regulation theory of dreaming. Research focusing on recently divorced individuals experiencing depression found that participants who dreamed about their ex-spouses were more likely to show significant improvement in their mood one year later, particularly if their dreams were vivid and emotionally rich. Another study found that people who dreamed about stressful events they had experienced before sleep woke up feeling more positively about the events the next day, suggesting that dreams can help transform emotional distress into resilience.
Recent brain imaging studies support this idea. People who frequently experience fear-related dreams show reduced activation in fear centers of the brain during waking life, hinting that these dreams may serve as a kind of overnight therapy session, helping us better regulate our emotions when awake.
Ultimately, Barrett suggests that we may be asking the wrong question. 'We'd rarely ask the analogous question: 'What is the purpose of thinking?'' she says. Just as waking thought serves many functions—from planning to problem-solving to daydreaming—dreams likely do too. 'The value of dreaming lies in its difference. It's a distinct mode of thought—one that supplements and enriches our waking cognition.'
In fact, some researchers believe dreams offer a unique mental space for solving problems that stump us during the day. In this altered brain state, regions responsible for imagery become more active, allowing the mind to solve problems requiring visualisation. History is full of famous examples: Mary Shelley reportedly dreamed the central scenes of Frankenstein; German chemist August Kekulé envisioned the ring structure of benzene in a dream; and Russian chemist Dmitri Mendeleev dreamed his final form of the periodic table of the elements.
In the end, dreams may serve many purposes—or none at all—but they remind us that even in sleep, the brain never truly rests.
This story is part of Popular Science's Ask Us Anything series, where we answer your most outlandish, mind-burning questions, from the ordinary to the off-the-wall. Have something you've always wanted to know? Ask us.
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New York Post
5 days ago
- New York Post
Lock into longevity at Lanserhof Sylt, the iconic German wellness retreat
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Yahoo
6 days ago
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Half of ordinary matter in universe has long been 'missing.' Astronomers just found it.
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6 days ago
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Half of ordinary matter in universe has long been 'missing.' Astronomers just found it.
Half of ordinary matter in universe has long been 'missing.' Astronomers just found it. Revelations made possible by studying radio waves hurtling through space suggest that violent cosmic forces have played a role in the remote locations of almost all of the "missing" matter. Astronomers have long estimated that ordinary matter – basically, anything other than dark matter – makes up only a fraction of the known universe. The conclusion stemmed from a complex calculation involving observed light left over from the Big Bang roughly 13.8 billion years ago. But there was one major problem: they had no clue where about half of it was. Now, it seems as if a team of astronomers has finally tracked down that missing "ordinary" matter, which they discovered hiding as gas spread out in the vast expanses between galaxies. Revelations made possible by studying radio waves hurtling through space suggest that violent cosmic forces have played a role in the remote locations of almost all of the "missing" matter. "The question we've been grappling with was: Where is it hiding? The answer appears to be: in a diffuse wispy cosmic web, well away from galaxies," Harvard University astronomy Liam Connor, lead author of the study, told Reuters. What is 'missing' matter? Ordinary matter makes up everything from the cosmic (planets and stars) to the earthly (people and trees.) But it only accounts for about 15% of matter in all of the known universe. The vast majority of matter is dark – invisible until it is detected only through its gravitational effects. Unlike dark matter, ordinary matter emits light in various wavelengths, which allow it to easily be seen. Still, scientists have long struggled to account for where all of it is located since a large chunk of ordinary matter is spread so thin among galaxies and the vast spaces between them. For that reason, about half of ordinary matter has long been considered missing. What are fast radio bursts? Cosmic waves help measure matter Until now. Powerful bursts of radio waves emanating from 69 locations in the cosmos have helped researchers at long last find the missing matter. The discovery came from a team of astronomers at the California Institute of Technology and the Center for Astrophysics, a research institute jointly operated by the Harvard College Observatory and Smithsonian Astrophysical Observatory. The team studied brief, bright radio flashes in the distant cosmos, called fast radio bursts (FRBs), to illuminate the matter lying between the radio waves and Earth. Astronomers have been studying fast radio bursts from across the universe since 2007 when the first millisecond-long burst was discovered. The bright burst of electromagnetic radiation may be brief, but fast radio bursts are so powerful that they produce more energy than what our sun emits in an entire year, astronomers say. The 69 radio frequencies the team studied were located at distances ranging up to about 9.1 billion light-years from Earth – making the furthest one the most distant fast radio burst ever recorded. The previous record was a fast radio burst documented about 8 billion light-years away in 2023. By measuring how the light from the radio bursts spread and dispersed – not unlike how a prism turns sunlight into a rainbow – while traveling toward Earth, the astronomers were able to determine how much matter was in their path. "If you see a person in front of you, you can find out a lot about them," Vikram Ravi, a Caltech astronomer who coauthored the study, said in a statement. "But if you just see their shadow, you still know that they're there and roughly how big they are." Findings will help understand galaxy growth The results revealed that about 75% of the universe's ordinary matter resides in the space between galaxies, also known as the intergalactic medium. How did it all end up in the middle of nowhere? Astronomers theorize it happens as gas is ejected from galaxies when massive stars explode in supernovas, or when supermassive black holes inside galaxies expel material after consuming stars or gas. The remaining 15% of the "missing" matter exists within either galaxies in the form of stars and cold galactic gas, or in the halos of diffuse material around them, according to the researchers. While this distribution is in line with predictions from advanced cosmological simulations, this is the first time it has been observed and confirmed, the researchers claim. The findings will help researchers better understand how galaxies grow. Caltech is also planning for its future deep-space radio telescope in the Nevada desert, the DSA-2000, to build upon the findings when it becomes operational. The radio array is being planned to detect up to 10,000 fast radio bursts per year. The findings were published June 16 in the journal Nature. Contributing: Reuters Eric Lagatta is the Space Connect reporter for the USA TODAY Network. Reach him at elagatta@
