Why Do We Forget Our Dreams?
5 min read
Last Modified 14 July 2022 First Added 10 May 2017
Having eight hours of sleep every night means we spend roughly a third of our life asleep. With this in mind, it seems strange that we don’t remember any of this time, even if we spent the whole night experiencing the most tremendous dreams. Let’s explore why this happens in more detail…
It is during REM (rapid eye movement) sleep, that we tend to do most of our dreaming as this is when our brain activity increases. A team of researchers studied mice, to discover why we forgot our dreams. They found that REM sleep may also be a period when our brain ‘actively forgets’. They suggest that after a good night’s sleep, our brain does not remember new information because of the activation of a specific group of neurons from the melanin-concentrating hormone (MCH) produced during REM sleep. This molecule is commonly associated with regulating appetite but now due to scientific research, it is also related to sleep.
Another reason why we forget our dreams so quickly is that we tend to filter out information that isn’t important or doesn’t grab our attention. And this is not just relevant to dreaming but also our everyday life, as we tend to only remember thoughts that we think about frequently or have personal resonance. Maybe you’re thinking about a job interview or to pick your kids up from school, whatever it is, thinking about valuable matters stimulates our dorsolateral prefrontal cortex (DLPFC), which is the part of our brain that aids our memory.
This would mean that we tend to forget about our dreams because our unconsciousness registers them as irrelevant. Yet, even though we forget most of our dreams, there are still some that we can recall in the morning as they must have stimulated our DLPFC. In other words, you must have dreamt about something that holds value to you.
In 2013, a study in cognitive psychology revealed that there is an existing neurological difference between those who can recall most of their dreams and those who fail in doing so. Researchers used different levels and frequencies of sound, along with occasional and random first names, to encourage both excitability and wakefulness in the patients while they were sleeping.
What they then found is that participants who were awake more often in the night had a high percentage of dream recall. They also found that those participants who had already displayed a strong ability to recall their dreams were able to process the first names they heard while awake, though no difference existed between the different sleepers once they were in REM sleep.
“In this sleep stage, the alpha waves increased and led the participants to wake up. In other words, the main difference between the groups was those who recalled their dreams woke up more periodically throughout the night. They were awake, on average, for 30 minutes during the night, whereas the low recallers were awake for 14 minutes.”
We formulate memories while we’re sleeping, which is why making sure we’re getting enough sleep is so important for learning. While we sleep, we consolidate what we’ve learnt that day into our long-term memories, but this process only occurs in a deep sleep. We spend the night moving in and out of different sleep phases, meaning at some points in the night we are more awake or more asleep, depending on what point in the sleep cycle we are in.
As mentioned earlier, it is during the REM sleep stage that we tend to dream each night. At this point, our bodies are paralysed to prevent us from acting out our dreams, while our eyes move in reaction to what it is we’re dreaming about. REM sleep usually occurs 90 minutes after you fall asleep. And because your brain is more active at this time, you have more vivid dreams – they only last between 5 and 20 minutes yet they can seem much longer.
A dream is a collection of images, thoughts, feelings, and sensory experiences that we cannot control. However, now we know that it is possible to remember them, let’s explore how we can try to remember our dreams…
1. Consciously try and remember your dreams each morning, and keep your eyes closed whilst doing so to make sure you don’t get distracted.
2. Always keep a dream journal next to your bed so that as soon as you wake up in the morning you can jot down your memories.
3. Make time to explore new places and meet new people – if you do something unusual during the day, you are more likely to dream.
4. Create a comfortable sleep environment to make sure you rest well and enter the deep sleep cycle. You can do this by optimising the temperature of your bedroom and having a good quality mattress that supports you throughout the night.
5. Ensure you have a regular sleep cycle to make sure you have good quality sleep each night – this will make it unchallenging for you to remember your dreams. Don’t worry if you do wake up during the night, as it is easiest to remember your dreams immediately following REM sleep.