Why do we forget our dreams?


You are halfway through saving a doomsday world from extraterrestrials or spending a night with a lost lover, when suddenly the sound of your alarm enters these storylines and comes to spoil the party. We’ve all been there, the feeling of waking up from a vivid dream that had us thinking we were among the likes of Quentin Tarantino or Christopher Nolan, but why then almost uncontrollably do we seem to forget these dreams as the day goes by. While scientific knowledge of dreams is still very undeveloped, there are two interesting evolutionary theories for why this happens.

Both theories stem from the fact that remembering these dreams, regardless of how cool they may be, are nonessential and sometimes even harmful to humans.

The first theory explains that our forgetfulness occurs as a natural response to continue learning and survival: for instance, in early cavemen, dreams of escaping lions by leaping off a cliff would not bode well when chased by a real lion.

The second evolutionary theory for dream forgetfulness was developed by Francis Crick, the co-discoverer of DNA. Crick believed that the function of dreams is to weed out unneeded thoughts and memories that accumulate over time in the brain, and dream recall defeats this primary evolutionary goal of dreaming. Our forgetfulness is generally attributed to neurochemical conditions in the brain that occur during REM sleep, a phase of sleep characterized by rapid eye movements and dreaming (1). It is interesting to note that after five minutes of a dream ending, we forget 50 percent of its content, and 90 percent of our dream’s detail is lost only 10 minutes later. Since most people wake up and immediately start thinking about how to start their day or other significant thoughts, these end up being the ones that get remembered. According to Crick, remembering dreams can leave the brain cluttered with useless information.

But what is it about dreams that make them so easy to forget, even when they can be so fascinating and graphic? It turns out it has to do with the nature of dreams, compared to reality. We are accustomed to remembering the past chronologically, linearly, and in terms of cause and effect. Dreams, however, are not always neatly arranged in time and effect — they meander and drift through different memory and emotional connections (2). Also, since dreams occur in deep sleep when a person is at rest, moving too much upon waking up can disrupt the memory of the dream much quicker.

After reading this, it may seem like grasping on to those vivid details of your precious dreams are not possible. While this is partially true, there are clearly methods to help with dream recall if one really cares to do so. Having to face and realize the construct of dreams (nonlinear, non sequential, etc), thinking about the dreams and only the dreams upon waking up, and limiting movement upon waking up can help someone remember more and more of those meaningful details of a lifelike dream. Also, writing down one’s memories of a dream upon waking up helps to recall more of the specific details. Using these methods can help to find those dreams our subconscious slept on.



Hartmann, E. (2011, May 01). Why Do Memories of Vivid Dreams Disappear Soon After              Waking Up? Scientific American. Retrieved February 20, 2018, from                                    https://www.scientificamerican.com/article/why-do-memories-of-vivid-dreams/

Oldis, D. (2015, August 27). Why Do We Have Trouble Remembering Our Dreams?               Retrieved February 20, 2018, from                                                                                     https://www.huffingtonpost.com/dreamscloud/remembering-                                           dreams_b_8009552.html