You thought you dreamed this before, but you didn't: How our mind blurs reality, memory and emotions

The brain’s mechanisms for recognising familiar experiences can misfire

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5 MIN READ
When we sleep, our brains don’t simply shut off. Instead, they embark on a process of sorting, consolidating, and reconstructing memories.
When we sleep, our brains don’t simply shut off. Instead, they embark on a process of sorting, consolidating, and reconstructing memories.
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Dreams are the real mind games.

Dubai-based Anushree Samolienko, a homemaker was sure that she had this dream before: She was running on an athlete’s track as she used to do in school and her opponent tripped her up and she fell, and everyone was watching her. “It felt so real that I woke up with a start and the feeling that I’ve had this dream before,” she says. As she wracked her brains, she just couldn’t remember exactly when or what it was.

Finally, she came to the rather unsatisfying conclusion that she hadn’t ever dreamt of such a thing before. But she remembers the intense feeling of deja-vu and anxiety of why she was suddenly dreaming of her school and the athlete’s track, when in fact, she had left behind athletics years ago.

It’s a curious and disorienting experience when your mind blurs the lines between reality, memory, and dreams. Did you truly dream that before, or is your mind simply playing tricks on you?

A dream may feel strangely familiar because it’s pulling fragments of memories and weaving them into an entirely fresh narrative, one that mirrors something from your past, even if the events themselves never actually happened.

How memory works

According to Melina Samuel, a UK-based neuropsychiatrist, "Our brain processes memory and perception. The brain’s mechanisms for recognising familiar experiences can misfire, creating a sense of familiarity where none exists." This phenomenon is often explained through the theory of dual processing, where two systems in the brain—one conscious and one unconscious—work in parallel but sometimes produce conflicting sensations.

When you wake from a dream feeling as though you’ve experienced it before, it's your brain’s way of creating a sense of familiarity. This can be traced to how the brain handles memories—both in waking life and during sleep.

Recurring themes in dreams are often tied to unresolved emotional experiences or chronic stress.

How our brain reconstructs and mixes memories during sleep

When we sleep, our brains don’t simply shut off. Instead, they embark on a process of sorting, consolidating, and reconstructing memories.  Our minds draw from the vast reservoir of past experiences, mixing them with current thoughts, emotions, and even unconscious impulses to create a dream. However, this process isn’t flawless, and sometimes the boundaries between what’s real and imagined blur.

So, if you’ve ever woken from a dream feeling like you’ve experienced it before even though the scenes are new, it’s because our brain has a knack for reconstructing memories, explains Samuel. “A dream may feel strangely familiar because it’s pulling fragments of memories and weaving them into an entirely fresh narrative, one that mirrors something from your past, even if the events themselves never actually happened."

This phenomenon is rooted in the consolidation of memories, a process where the brain takes new information from the day and stores it for the long term. During sleep—particularly during REM sleep, which is the phase most associated with vivid dreams, —the brain revisits memories, strengthening and embedding them in the neocortex, while the hippocampus plays a pivotal role in organizing and stabilizing those memories, as a 2010 study The memory function of sleep, published in  Nature Reviews Neuroscience.

However, the brain doesn’t just neatly file memories: It blends fragments from the past, with current sensations, emotions and even unconscious thoughts. This unusual fusion results in a dream that feels oddly familiar, even though it’s entirely fabricated. According to a 2001 study, Sleep-dependent memory consolidation, published in Nature, this memory reconstruction during dreaming helps explain why our dreams often seem to incorporate bits and pieces of our waking lives—sometimes in distorted, unexpected, or surreal ways.

So, the next time you wake up with a lingering feeling of having “dreamed this before,” it’s simply your brain’s way of piecing together the puzzle of your past and present in ways that make sense—at least to your subconscious.

If you frequently dream about a specific place, person, or event that hasn’t been a part of your waking life, it might still feel like a recurring dream.

Why does a dream keep returning?

Have you ever had a recurring dream where you're falling, being chased, or running endlessly? It may not be the same dream each time, but the emotional patterns are strikingly similar. According to neuropsychiatrists Samuel and Sushmita Chatterjee, these recurring themes in dreams are often tied to unresolved emotional experiences or chronic stress.

For example, if you frequently dream about a specific place, person, or event that hasn’t been a part of your waking life, it might still feel like a recurring dream. "Even though the details change, the emotional essence of the dream can remain constant, giving the illusion of repetition," explains Chatterjee. Your brain draws upon patterns from past emotional experiences, making these dreams feel familiar, even when the events themselves are entirely fabricated.

Emotions: The glue that binds dream themes

What emotional residue did your dream leave behind? Did you wake up with anxiety or a sense of dread? According to Chatterjee and Samuel, the emotional intensity of a dream plays a huge role in shaping how we perceive it. Dreams that stir up strong emotions—like fear, anger, or even joy—tend to trigger vivid recollections. If you’ve had similar emotions in previous dreams, your brain may use those emotional patterns in a new dream, creating an emotional familiarity even though the details differ.

“Even though the events are different, the emotional patterns can trick the mind into thinking it's experienced something before,” Chatterjee adds.

Understanding the mystery of dreams

Despite decades of research, dreams continue to perplex and vex us. A 2005 study published in Sleep Medicine Reviews suggests that dreams also serve to consolidate emotional memories, especially those that remain unresolved. When such emotions aren’t fully processed, they may manifest as recurring dreams that feel oddly familiar, even as the details shift. The emotional essence of the dream remains constant, tricking your brain into believing you've experienced it before.

There’s something almost charming in the mystery. After all, dreams are one of the few realms where time and reality can blur, allowing us to experience moments where past and present seem to melt together.

So, next time you wake up with that unsettling sense of déjà vu from a dream, remember: It’s simply your brain making sense of the world, sometimes in ways that feel a little too familiar.

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