The Science and Psychology of Dreams: Why Do We Dream?

Research is bringing us closer to understanding the psychology of dreams and the dream state, and the functions it serves.

Why Do We Dream?

The enigma of dreams has fascinated scientists and laypeople alike for centuries. Why do we dream? What’s their purpose? Do they serve a cognitive or psychological function? Can we interpret meaning from them, or are they entirely meaningless?

Given the subjective nature of dreams, it’s difficult to test hypotheses.

These are questions that scientists have been trying to answer for decades, with Freud, the founding father of psychoanalysis and dream analysis, publishing a manifesto on the subject in 1899.

Since then, technological advancements – in particular the invention of electroencephalograms (EEGs) by psychiatrist, Hans Berger – have allowed researchers to delve more deeply than Freud was able, producing new theories and a deeper understanding of dreams.

Given the subjective nature of dreams, it’s difficult to test these hypotheses. However, supporting research does exist to support some of the ideas.

Before we come to the various theories of what dreams are and why they happen, let’s first take a look at what takes place in the brain during the dream state.

What Happens in the Brain When We Dream?

The invention of the EEG was revolutionary in the field of dream research – finally scientists were able to do what Freud never could: measure brain activity during sleep. The new technology produced a way to monitor and document the brain waves in a dream state. And the findings were surprising.

The discovery of REM sleep revolutionised our understanding of sleep and dreaming.

Eugene Aserinsky, a pioneer in sleep research, is credited with discovering REM (rapid eye movement) sleep using EEG in 1951, publishing a paper in Science journal in 1953¹.

The story goes that Aserinsky was testing the EEG on his son, Armond. Aserinsky was set up and monitoring the EEG in one room, and Armond was sitting taking his father’s instructions in an adjacent room. Armond fell asleep, and the brain activity measured by the EEG slowed down as expected. But after some time it ramped up again.

Aserinsky went to check on his son, expecting to find him awake – and was shocked to find him still fast asleep. Thus, the REM stage of sleep was discovered, leading to new research and revolutionising our understanding of sleep and dreaming.

Essentially, what the EEG readings showed Aserinsky is that brain activity during REM sleep mimics that of when we are awake, and more recent research explains what’s happening.

Research has shown that that dreams can be a source of personal insight.

A 2011 study of dreams observed that increased frontal lobe theta activity in REM sleep is the same as that used in waking life for the successful encoding and retrieval of autobiographical memories². The prefrontal cortex is responsible for executive functions such as decision-making and emotional processing, which can also explain the conscious-like experience of dreaming.

Another study used MRI techniques to show the link between vivid and emotionally tense dreams and parts of the hippocampus and the amygdala³, both of which play an important role in memory. The hippocampus is involved with the consolidation of information from short-term memory to long-term memory, while the amygdala is known to be pivotal in the processing and memory of emotional reactions.

Of course, while this goes some way to explaining what’s happening neurologically, it doesn’t address the function dreams have. But there are a handful of theories.

George Lakoff, American cognitive linguist and philosopher, suggested that abstract symbols in dreams represented real hardships. While there may not be enough research to categorically confirm that dreams are symbolic, if you ask around, you’ll likely find anecdotal evidence to support the idea.

Either way, research has shown that that dreams can be a source of personal insight⁴.

Various Theories of Dreaming

There are several different hypotheses about the psychology of dreams and the function of dreaming, with some suggesting that the only purpose they serve is in cognitive processes, and others theorising they have significant meaning for the dreamer.

Freud’s Theory of Unconscious Wish Fulfilment

Sigmund Freud, the father of modern psychoanalysis, theorised that dreams are ‘the royal road to the unconscious’. 

He believed that our dreams represent our deepest desires, and that literal events, known as manifest content, are symbolic of unconscious desires and thoughts, known as latent content⁵.

Jung’s Theory of Compensation and Self-Portrayal

Carl Jung, a contemporary of Freud, believed that dreams are symbolic and can reveal elements of a patient’s psychological and physiological needs⁶.

It’s important to pay most attention to the feelings that are invoked by a dream.

Jung theorised that unconscious needs appear symbolically in dreams, and paying attention to them can unveil messages with personal meaning. In other words, if there’s something happening in the real life of which we’re not consciously aware, our dream content can indirectly draw our attention to it.

For example, if you’re working at a job where you don’t feel stretched, you might have a dream where you’re in the office but instead of working you’re lounging around a pool which has appeared. This may demonstrate your feelings of your working be too easy.

However, it’s always important to pay most attention to the feelings that are invoked by a dream. Because using the above example, an alternative meaning could be that you feel inadequate or intimidated around your other colleagues, especially if you’re in a bathing suit and everybody else is dressed.

Threat Simulation Theory

Finnish cognitive neuroscientist and psychologist, Antti Revonsuo has a different hypothesis, known as Threat Simulation Theory (TST). He speculated that the purpose of dreaming is an evolutionary biological defence mechanism.

The TST hypothesis suggests that we may have developed dreams to enhance our threat perception and avoidance during conscious experiences.

Revonsuo evaluated the dreams of severely traumatised children and compared them with the dreams of children less exposed or not exposed to threatening events⁷. Researchers proposed that those children with severe traumatic experiences would exhibit an increase in dreams with threatening content, or frequent nightmares.

The results supported the TST hypothesis, suggesting that we may have developed these types of dreams as the brain’s way of simulating real-life threatening situations, to enhance our threat perception and avoidance during conscious experiences.

Activation-Synthesis Theory

Another theory is that dreams don’t actually have meaningful substance – they are merely a result of normal electrical brain impulses pulling random thoughts and visual images from our memories and external stimuli⁸.

According to this theory, the brain acts as a completely random dream generator, and that’s the reason our dreams often feel bizarre – because they do not follow a narrative structure; we assign meaning after the event.

Continual-Activation theory

According to the continual-activation theory, the primary role of dreams is to process memory, including discarding unimportant information and a process called sleep-dependent memory consolidation, which is essentially transferring short-term memories into long-term memories.

Conscious-related memory (declarative memory) is processed during non-REM sleep, while unconscious related memory (procedural memory) is processed during REM sleep.

The theory suggests that while the unconscious brain is engaged processing procedural memory during REM sleep, the conscious part of the brain slows down significantly. This prompts a stream of data, ie. your dreams, to flow through the conscious part of the brain, to keep it running at a reduced level of activity, in a process coined ‘continual-activation’.

Emotional Regulation

Dreaming may help us to regulate emotional states in the real world.

Another theory is that dreaming is connected to mental health, providing a ‘safe’ environment to work through traumatic life events and the associated negative emotions⁹. 

In other words, through dreaming, the unconscious mind attempts to bring a message to the surface in order to ‘force’ us to confront an issue we may be avoiding when we’re awake¹⁰. The assumption is that this process helps us to regulate emotional states in the real world.

Can You Learn to Interpret Your Own Dreams?

Scientific dream theories aside, it’s a popular belief that dreams do have personal meaning. And given the fact common themes come up again and again in the dreams of different people across different cultures, it’s not surprising that many people are convinced they hold significance.

We have the best recall about our dreams immediately after waking.

So where should you begin if you’re interested in understanding what messages your subconscious mind may be trying to convey to you via your dreams?

The best way to begin interpreting your own dreams is to keep a dream journal by your bed. We have the best recall about our dreams immediately after waking¹¹ (especially if waking from REM sleep, which is also when lucid dreams or vivid dreams are most likely to occur¹²), with clarity diminishing over time. With that in mind, it’s recommended to note down what you remember immediately upon waking to ensure details are not lost.

Learn more about lucid dreaming.

Then, consider what some of the symbols may represent from your everyday life and, critically, what feelings the dream brought up for you. Often, you’ll experience an ‘aha!’ moment if you make a relevant and valid connection to your daily life, which may be beneficial in terms of personal growth.

Sources

1. ASERINSKY E, KLEITMAN N. Regularly occurring periods of eye motility, and concomitant phenomena, during sleep. Science. 1953 Sep 4;118(3062):273-4. doi: 10.1126/science.118.3062.273. PMID: 13089671.
2. Marzano C, Ferrara M, Mauro F, Moroni F, Gorgoni M, Tempesta D, Cipolli C, De Gennaro L. Recalling and forgetting dreams: theta and alpha oscillations during sleep predict subsequent dream recall. J Neurosci. 2011 May 4;31(18):6674-83. doi: 10.1523/JNEUROSCI.0412-11.2011. PMID: 21543596; PMCID: PMC6632857.
3. De Gennaro L, Cipolli C, Cherubini A, Assogna F, Cacciari C, Marzano C, Curcio G, Ferrara M, Caltagirone C, Spalletta G. Amygdala and hippocampus volumetry and diffusivity in relation to dreaming. Hum Brain Mapp. 2011 Sep;32(9):1458-70. doi: 10.1002/hbm.21120. Epub 2010 Aug 25. PMID: 20740648; PMCID: PMC6869846.
4. Edwards CL, Ruby PM, Malinowski JE, Bennett PD, Blagrove MT. Dreaming and insight. Front Psychol. 2013 Dec 24;4:979. doi: 10.3389/fpsyg.2013.00979. PMID: 24550849; PMCID: PMC3872037. 
5. Zhang W, Guo B. Freud’s Dream Interpretation: A Different Perspective Based on the Self-Organization Theory of Dreaming. Front Psychol. 2018 Aug 23;9:1553. doi: 10.3389/fpsyg.2018.01553. PMID: 30190698; PMCID: PMC6115518.
6. Khodarahimi S. Dreams In Jungian Psychology: The use of Dreams as an Instrument For Research, Diagnosis and Treatment of Social Phobia. Malays J Med Sci. 2009 Oct;16(4):42-9. PMID: 22135511; PMCID: PMC3216128.
7. Valli K, Revonsuo A, Pälkäs O, Ismail KH, Ali KJ, Punamäki RL. The threat simulation theory of the evolutionary function of dreaming: Evidence from dreams of traumatized children. Conscious Cogn. 2005 Mar;14(1):188-218. doi: 10.1016/S1053-8100(03)00019-9. PMID: 15766897.
8. Hobson, J. A., & McCarley, R. W. (1977). The brain as a dream state generator: An activation-synthesis hypothesis of the dream process. The American Journal of Psychiatry, 134(12), 1335–1348. doi: 10.1176/ajp.134.12.1335.
9. Scarpelli S, Bartolacci C, D’Atri A, Gorgoni M, De Gennaro L. The Functional Role of Dreaming in Emotional Processes. Front Psychol. 2019 Mar 15;10:459. doi: 10.3389/fpsyg.2019.00459. PMID: 30930809; PMCID: PMC6428732.
10. Malinowski, J. (2017). High thought suppressors dream more of their negative waking-life experiences than low thought suppressors. Dreaming, 27(4), 269–277. doi: 10.1037/drm0000061
11. Dal Sacco D. Dream recall frequency and psychosomatics. Acta Biomed. 2022 May 11;93(2):e2022046. doi: 10.23750/abm.v93i2.11218. PMID: 35546027; PMCID: PMC9171870.
12. Ursula Voss, Romain Holzmann, Inka Tuin, Allan J. Hobson, Lucid Dreaming: a State of Consciousness with Features of Both Waking and Non-Lucid Dreaming, Sleep, Volume 32, Issue 9, September 2009, Pages 1191–1200, doi: 10.1093/sleep/32.9.1191