Why Do We Remember or Forget Our Dreams?

It's quite common to be in the midst of an enthralling dream, only to have it end abruptly by the act of waking up. While the memory of the feeling remains, the memory of the actual dream, unfortunately, fades away. Why does this happen? Why do we remember certain dreams, while forgetting others? Let's find out...


Dreams are a combination of images, ideas, emotions, and sensations, that are witnessed involuntarily by the mind during specific stages of a sleep cycle. Some of these are wondrous to behold, elating us to a new level, while others speak to our innermost fears and strike terror. However, this all ends when a person wakes up, comes back to reality, and realizes all of it was just a figment of their imagination.

However, when people try to share the details, they find themselves at a loss, as they can't manage to remember what they had dreamed. This is quite common; in fact, the majority of the population does not even remember dreaming, much less the content of that dream, and hence, believe themselves to be incapable of this mental phenomenon. Very few people can claim to successfully remember their dreams, but even in case of such people, the entirety of the dream is not remembered, but mere fragments of the whole. According to various scientific studies, within the first five minutes of waking up, we manage to forget almost 50% of the dream, and the remaining 50% fades out gradually as we go about our routine activities.

The scientific study of dreams is called oneirology, and deals with deciphering the content, meaning, and purpose of dreams. The exact reason why we dream has not been elucidated, and the reason for their occurrence is yet unknown. However, it is not only humans who dream, but the phenomenon has been observed in various animals too, like cats, dogs, mice, etc. Hence, it is a universal phenomenon. In order to probe the depths of our dreams and decipher their meaning, one must first analyze them. But therein lies the problem, since, as mentioned earlier, remembering a dream is a fickle endeavor.

Why are Some Dreams Remembered, But Not Others?
Over the years, various theories have been suggested by researchers to explain why we forget or remember our dreams. These theories base their claim on a wide range of evidence, ranging from brain wave study to psychoanalytic motivation behind the dream itself. These theories are as follows:

➤ Sigmund Freud, a famous psychologist, proposed the theory of repression. He claimed that, all content matter visualized and sensed in a dream is a direct result of the brain's attempt at wish fulfillment. Hence, if one were unable to recall a dream, it implied that the brain had blocked out the episode, either because the wish itself was too emotional to be handled by our system, or that the whole dream or the wish behind it were somehow traumatic. He claimed that, in forgetting the dream, the brain was enforcing self-preservation.

➤ The salience theory suggests that some dreams are forgotten simply because they are not interesting enough. If nothing noteworthy occurs in the dream, the brain chooses not to expend energy in recording a memory of it. This is supported by various studies which have concluded the same results. Another point in favor of this theory is the fact that, the neurotransmitters responsible for converting short-term memories into long-term memories are suppressed during REM sleep, when dreams occur. Therefore, it causes us to retain no memory of the dream.

➤ The interference theory, associated with the loss of stored information in the brain, is also another plausible explanation for forgetting a dream. According to this claim, due to the interference of old memories and the new data presented by the dream, confusion is caused between the two sets of data, causing the brain to forget the new data.

➤ A recent study has proved that, the chances of recollection of a dream depend on the level of brain activity exhibited by the medial prefrontal cortex and the temporoparietal junction, areas of the brain associated with attention orienting towards external stimuli. Higher levels of activity in both areas, while awake as well as while sleeping, increased the recall of a dream. This is thought to occur since the increased activity promotes intra-sleep wakefulness, which in turn facilitates successful memory encoding.

➤ Another theory proposes that, we remember dreams only when we awake during the REM stage of the sleep cycle. This is due to the fact that, during the REM stage, theta waves are produced on a higher level, and alpha wave production is reduced. Theta waves have been claimed to facilitate the formation of declarative and explicit memories, while alpha waves are associated with wakefulness that renders the brain sensitive to external stimuli. Hence, in the REM stage, high levels of theta waves would facilitate the remembrance of a dream, while low levels of alpha waves would suppress the brain from reacting to environmental stimuli that may disrupt the dream. People who wake up during the non-REM stages show very little or no recollection of the dream, since the levels of alpha waves are high and those of theta waves are low during the non-REM stages of the sleep cycle.

Other factors also affect the dream recall ability of an individual. On an average, women are more likely to have vivid dreams and remember them after waking up as compared to men. Also, children show an increased capacity to remember their dreams as well. The ability to recall dreams is however, still not an exact science, and needs further research to elucidate fully.