Have you ever had that one reoccurring dream and you just cannot seem to understand why? Or maybe you have had dreams involving dramatic changes in your life, such as a break-up or death. I am sure you have had a few dreams involving random people that you haven’t thought about in years, which cause extreme confusion when you wake up. Why do we dream about the things we dream abou and what causes these dreams?

According to the Merriam-Webster dictionary, a dream is “a series of thoughts, images, or emotions occurring during sleep and especially during REM sleep.” While technology is greatly improving, therefore making studying dreams studying dreams much easier, “[w]hy we dream is still one of the behavioral sciences’ greatest unanswered questions. Researches have offered many theories- memory consolidation, emotional regulation [and] threat simulation.” The Department of Psychology in Tucson, Arizona supports the claim that “there is currently no convincing explanation for why we dream or what we dream about.”  However, Jessica D. Payne and Lynn Nadel believe in a strong relationship between sleep and memory. They believe that “dreams reflect a biological process of long-term memory consolidation, serving to strengthen the neural traces of recent events, to intergrade these new traces with older memories and previously stored knowledge, and to maintain the stability of existing memory representations in the face of subsequent experience.” They are aware that multiple neurotransmitters and neurohormones are involved in the dreaming process, but they chose to focus their study on a stress hormone cortisol. “Cortisol is a steroid hormone, and is produced in humans within the adrenal gland. It is released in response to stress and low blood-glucose concentration.”  Along with adrenaline, cortisol creates memories of short term-emotional events.

There are currently two major types of sleep that are heavily studied. One type is rapid eye movement, or REM sleep. REM sleep goes through roughly 90 minute cycles “and alternates with four additional stages known collectively as NREM sleep- the second type of sleep. Slow wave sleep is the deepest of the NREM phases and is the phase from which people have the most difficulty being awakened” (Payne and Nadel). The two different stages of sleep occur due to neurochemical fluctuations. Until recently, nearly all of the research on dreams was focused on REM sleep. While dreams are undoubtedly present during REM, recent studies show that dreams also occur during the NREM stages as well. However, out of 29 REM and 33 NREM studies, only 50% of those who dreamt during NREM remembered their dreams. On the other hand, nearly 81.8% of the 29 REM participants were able to remember their dreams. Researches have often found that the dreams we have during REM are the dreams that give us superpowers. In “REM dreams, it is possible to walk through walls, fly, interact with an entirely unknown person as if she was your mother, or stroll through Paris past the Empire State Building.” (Payne and Nadel). While episodic memory is highly functional in NREM sleep, it is not in REM sleep. Episodic memory “refers to knowledge about the past that incorporates information about where and when particular events occurred” (Payne and Nadel). Therefore, it seems clear that most of the bizarre dreams we have occur during the REM stages of sleep, and dreams relating to thoughts in our memory take place during NREM sleep.

Emotional regulation is another common theory on why we dream. There are strong ties between nightmares and emotional regulation nightmares and emotional regulation, and “a majority of nightmare theories converge on the view that a principal function of dreaming is the regulation of emotion and that some alteration of this emotion regulation leads to nightmares.” As believed by Freud, “adaptive functions of nightmares have been described as assimilating repressed anxiety, or transforming shame into fear. Nightmares have also been considered as emotionally maladaptive, for example, as failing to master trauma” (Nielson and Lara-Carrasco). It is evident that emotional regulation is a theme that is consistently displayed in studies of nightmares.

The threat simulation theory relates dreaming to an entire different spectrum than other scientists have previously studied. This theory “states that dream consciousness is essentially an ancient biological defense mechanism, evolutionarily selected for its capacity to repeatedly simulate threatening events.”  This has become evolutionarily useful because the dreams allow the rehearsal of “cognitive mechanisms required for efficient threat perception and threat avoidance, leading to increased probability of reproductive success during human evolution.” Whoa, so does this mean that our dreams prepare us for real life situations by introducing them to the brain beforehand? One belief on why this occurs is that threatening events that a person experiences while they are awake will lead to changes throughout their body, such as threat simulation responses. These responses cause “an increased severity of threatening events in dreams” (Valli, Revonsuo, and Ismail). This has been proven through studies comparing children who live in unstable environments compared to children who are raised in healthy environments. Children who live in an environment where their “physical and psychological well being is constantly threatened should have a highly activated dream production in threat simulation system, whereas children living in a safe environment that is relatively free of such threat cues should have a weakly active system” (Valli, Revonsuo and Ismail). Through studies on Finnish and Kurdish children of different upbringings, researchers were able to support their hypotheses further. They found that “the severely traumatized children reported a significantly greater number of dreams and their dreams included a higher number of threatening dream events” (Valli, Revonsuo and Ismail). The threats in the dreams of traumatized children were also far more severe and serious compared to the threats of less traumatized children. These results were found through administering surveys to children regarding their dream patterns. While that may not be the best and most reliable method, I cannot think of a better one to use. Personal surveys have multiple issues, including response bias and untruthful answers. However, there is no other benefical way to test individuals on whether they remembered their dreams or not, and what these dreams were about.

This study leads me to believe that trauma has a strong influence on dreams, and what we dream about. I think that our mind is subconsciously thinking about events that happen in our day-to-day life, and things that worry us. This would therefore lead to more threatening dreams for those who live in dangerous and traumatizing environments, or for individuals who are more anxious than others. I have noticed in my own life that I tend to remember dreams more when I am anxious about something. I think that it is also evident that the REM cycle plays the key role in dreaming, and that all of these functions must come together to cause us to have specific dreams involving particular people.

While all of these theories make perfect sense individually, I think that they work best when tied together. I think that dreams are a result of a multitude of functions, and that there is not one specific thing that causes them. As technology advances further, it will become easier to understand and prove why we dream. Who knows, maybe within our lifetime we will know the true cause of dreams. Until then, I think that the memory consolidation, emotional regulation and threat simulation theories are all equally likely to cause dreams.