Why We Hear Noises In Our Dreams
You woke up this morning with tears in your eyes. During your dream the night before, you heard the voice of a long-lost relative. Their voice warmed your heart, but you wonder why you heard their voice at all.
The brain and sleep have an incredible connection. And while you might get a little shut-eye, your brain doesn't take a siesta. One of the areas that science has found isn't shutting down completely is your auditory information processing. Research in the Journal of Neuroscience demonstrates that the auditory cortical area doesn't shut down when you are sleeping. The study explored how the neurons were affected during sleep in monkeys, showing only a slight decrease in the flow of auditory information in both the primary and secondary cortical areas. Therefore, sounds around you could affect your dreams, like the TV being on or the voices in the room while you snooze. The sounds may also come from your internal sound memories.
Learn more about the auditory sensations you might experience during a dream and the most common dream sound. We'll also explore the different theories around why you dream.
Memory sounds flood dreams
While outside sources can contribute to the sounds you hear during sleep, they can also be part of your echoic memory (sound memory). According to WebMD, echoic memory is stored in the brain's long-term memory. Per research published in the journal Sleep, 53% of dreams can be traced to past memories, so talking to your sister while dancing on a train could be a stored memory of her voice.
A small study in PLoS One in 2020 showed that most of the audio impressions in dreams are voices. The study consisted of 13 participants who recorded their dreams after waking. They were to give details about settings, feelings, sounds, and thoughts. Of those sounds, a whopping 83% were of people talking in their dreams. Another 60% were dreamers talking to someone else. The study notes that most speech was clear and easy to remember, but there were also instances of a foreign language, laughing, screaming, and cheering. Researchers state that "the available evidence suggests that normal, healthy people usually experience internally generated auditory sensations an array of times every night" (via the British Psychological Society).
What are dreams?
Why do people dream, in the first place? This area of science is still being studied, but there are a few different theories out there. For example, Medical News Today states that dreams can represent desires and be interpretations of neural signals while sleeping. Additionally, as postdoctoral fellow Dheeraj Roy told the McGovern Institute, "Every time you learn something, it happens so quickly. The brain is continuously recording information, but how do you take a break and then make sense of it all?" Dreams are how we organize all the experiences, people, and emotions we experience, even when they appear bizarre.
It's not just our memories that affect our dreams; external stimuli have an impact on dreams, too. A study published in the Journal of Sleep Research states that olfactory stimuli affect the emotional content of dreams. Researchers used the smells of rotten eggs and roses to see how they affected participants' dreams; those who smelled the latter had more "positively toned" dreams, while those exposed to the former had more "negatively toned" dreams.
Additionally, a study in Current Biology demonstrates that nightmares could be reduced by listening to a tone associated with a cheerful ending. In the study, participants with nightmare disorder used targeted memory reactivation to turn the ending of their nightmare positive. A sound was played while they did this. Then, they listened to the sound while sleeping, and it worked to create more positive dream emotions.