You wake in the early hours of the morning with your heart beating fast and the unsettling sense that you’ve just emerged from a strange dream — but what was it? Vague images swim through your mind, faces you only half-recognize, and for a second you think it’s all coming back to you. Then you blink, and the memory is gone.
The subject of dream recall — that is, how and when and to what extent we remember our dreams — is a tricky topic, and one that’s fascinated researchers for decades. Why do we remember our dreams some nights, but not others? Why do some people seem to remember their dreams more often than others? We don’t have all the answers, but we know that our ability to remember our dreams in the morning most likely involves a complex set of factors including how we wake up, what our personalities are like, and what happens inside our brains while we sleep.
The Critical Waking Period
The first thing to keep in mind is that you most certainly dream, even if you don't remember doing it. Scientists generally believe that humans dream every night — and, probably, all night long.
“In every sleep stage, there’s some kind of subjective experience,” said Michael Schredl, a researcher in the sleep laboratory at the Central Institute of Mental Health in Mannheim, Germany, and an expert on dream recall. Researchers widely agree that the reveries experienced during REM sleep are generally more intense, he said, but some type of dreaming is likely present in all stages.
“Sometimes it can take up to 15 minutes that the brain is fully switched from one mode to another. This is the critical area for dream recall.”
And whether or not you remember your dream, according to Schredl, is probably influenced by a critical moment during the waking process.
“When the sleeper awakes, there’s this moment the brain has to switch from the sleep mode to wake mode,” he said. “Sometimes it can take up to 15 minutes that the brain is fully switched from one mode to another. This is the critical area for dream recall.”
Over the years, researchers have attempted to determine if distractions or interference during this critical waking period can have an effect on the sleeper’s ability to remember what he or she dreamed. But different studies have produced different results, meaning it’s still an open question. Schredl pointed out that some research suggests that waking suddenly — as opposed to gradually — can increase the likelihood of remembering dreams. But even this is a question that deserves more attention.
Personality Plays a Part
As we’re all subject to our own particular genetic makeup, there’s some evidence to support the idea that certain personality traits play a role in remembering dreams. Several studies have suggested that traits such as creativity and openness to different experiences may be associated with more frequent dream recall. One 2003 study in particular showed that people who were more imaginative and prone to daydreaming were more likely to remember their dreams.
People who frequently remember their dreams — “high recallers” — were twice as wakeful during the night as low recallers.
Other, more concrete, individual factors have been shown to play a role as well. In a 2007 chapter in the book The New Science of Dreaming (Vol. 2), Schredl pointed out that several large-scale surveys have suggested that the frequency of dream recall decreases with age.
Schredl and colleague Iris Reinhard also authored a 2008 meta-analysis on gender differences in dream recall. Drawing on 175 different studies over the years, they found that, overall, women tend to recall their dreams slightly more often than men do, although this effect is also somewhat dependent on age, as the trend seemed to be strongest among adolescents.
It’s All in your Head
In more recent years, researchers have begun looking at whether neurobiological processes — those occurring inside the brain — might also also affect dream recall.
In 2013, Perrine Ruby, a scientist at the French Institute of Health and Medical Research, along with a group of colleagues published a study suggesting that people who frequently remember their dreams — “high recallers” — were twice as wakeful during the night as low recallers. Additionally, high recallers’ brains were more reactive to sound stimuli (such as hearing names called out) while sleeping.
Ruby and her team demonstrated in a 2014 study that high recallers have greater blood flow in certain areas of the brain (which can indicate greater brain activity in these regions), both during sleep and wakefulness. Specifically, they found differences in brain activity in the temporoparietal junction, a part of the brain involved in processing information, and the medial prefrontal cortex, which contributes to decision-making and generating certain phases of sleep.
High recallers have greater blood flow in certain areas of the brain (which can indicate greater brain activity in these regions), both during sleep and wakefulness.
These results are in line with previous research, which already suggested that these brain regions play a key role in dream recall. Studies have indicated that people with damage to these parts of the brain can lose their ability to remember dreams at all, evidence that dream recall does originate from a specific area.
The Write Stuff
Despite all the research that’s been done, Schredl feels that the subject of dream recall remains poorly understood. But for those who remain unsatisfied with their dream-recall rates, there may be at least one way to increase the likelihood of remembering dreams — and it comes down to the power of suggestion.
Research has found that keeping a dream diary can substantially boost a person’s recall frequency (avid lucid dreamers always profess journaling as an excellent way of triggering in-dream awareness). It’s not clear why, but it may be that something about going to bed each night with the intention of remembering dreams in the morning and writing down the elements you remember — no matter how large or small — is a powerful tool.