Why do we dream?

Why do we dream? This question has intrigued scientists, philosophers and dreamers for centuries. Dreaming is complex and multifaceted. There are many theories and scientific research as to why dreams occur and what they mean, but there is still no concrete answer, and many aspects of this fascinating process remain a mystery.

Many people are fascinated by their dreams and actively try to understand them, often keeping dream journals or seeking interpretations from experts. This curiosity spans cultures and history, with dreams being a significant part of many traditions and philosophical and psychological practices. This blog aims to expand on this and explore scientific theories, cultural interpretations and the ongoing mystery of dreaming.

What Are Dreams?

Many definitions of dreams exist, and they can differ depending on the perspective, for example:

• From a psychological perspective – “A physiologically and psychologically conscious state that occurs during sleep and is often characterized by a rich array of endogenous sensory, motor, emotional, and other experiences” (American Psychological Association). Psychologically, dreams are often seen as a window into the unconscious mind, revealing desires, fears and unresolved conflicts.
• From a neurological perspective – “Dreams are experiences that occur during sleep, while we are disconnected from the environment” (Siclari et al. 2020). Neurologically, scientists believe dreams are the brain’s attempt to process information, emotions and experiences from the day.

Dreams predominately occur during the rapid eye movement (REM) sleep stage, which is part of the sleep cycle:

• Non-REM sleep (NREM) stage 1 – the lightest stage of sleep, where you drift in and out and can be awakened easily.
• Non-REM sleep (NREM) stage 2 – involves deeper sleep but is still a light state of sleep. Your body temperature drops and your heart rate begins to slow.
• Non-REM sleep (NREM) stage 3 – is often referred to as deep or slow-wave sleep, and you are less likely to be woken up by noise. Some may feel disorientated if woken up from this stage of sleep. This stage is crucial for physical restoration and memory consolidation.
• Rapid eye movement (REM) sleep stage 4 – characterised by rapid side-to-side eye movement, increased brain activity and vivid/memorable dreams. According to Mindwell, about 20% of a night’s sleep is in this stage.

It is interesting to note that while REM sleep is the most common time for dreaming, some dreams can also occur during the non-REM stages, though they tend to be less vivid and more fragmented. Sleepstation has further information on the sleep stages.

Dreaming is a remarkable and universal experience shared by all humans, regardless of cultural background, age or sex. However, the content, themes, frequency, vividness and recall of dreams can be highly variable across individuals:

• Content – can be influenced by daily experiences, emotions, memories and current life situations. For example, someone experiencing stress might have anxiety-laden dreams, while another might dream of pleasant events from their past. People from different cultures may have dreams that reflect their unique societal norms and values.
• Themes – common themes can be universal and experienced by many people, such as falling or losing teeth. However, the specific details and emotions associated with the dreams can vary widely.
• Frequency, vividness and recall – some people frequently remember their dreams in great detail, while others might recall only fragments or not at all. It can be influenced by many factors, such as age, sex, culture, personal experiences, health, sleep quality, stress levels and lifestyle choices. For example, women typically dream more often than men and can remember them more easily (Dreams).

Theories on Why We Dream

The purpose of dreams has fascinated thinkers for centuries, resulting in numerous theories, such as Freud’s Psychoanalytic Theory, Activation-Synthesis Theory, Information Processing Theory, Emotional Regulation Theory and Threat Simulation Theory.

Freud’s Psychoanalytic Theory

Sigmund Freud (1856-1939) was an Austrian neurologist and the founding father of psychoanalysis whose work has profoundly impacted the fields of psychology, psychiatry and even popular culture. He published a book in 1900, The Interpretation of Dreams, which provided a groundbreaking theory of dreams and an innovative method for interpreting them (Freud Museum London).

Freud believed dreams serve as a window into the unconscious mind (below the surface of conscious awareness), revealing hidden desires, memories, fears and unresolved conflicts. These elements are often repressed because they are socially unacceptable or cause psychological discomfort.

He also proposed that dreams represented the fulfilment of repressed wishes, often rooted in childhood experiences. They allow us to experience desires we cannot satisfy in our waking life and provide a safe space where individuals can express these wishes without consequence.

He suggested that two main parts make up our dreams:

• Manifest content – the actual storyline of the dream, including the images, thoughts and content we remember upon waking.
• Latent content – represents the hidden psychological meaning of the dream. Freud developed techniques for interpreting dreams to reveal the underlying latent content.

Freud’s theories have received significant criticism and reinterpretation over the years and can be deemed by some as controversial. Nevertheless, his psychoanalytic theory is one of the most famous relating to dreams and continues to influence how we think about the mind and its mysteries.

Activation-Synthesis Theory (Hobson and McCarley)

Two neuroscientists, J. Allan Hobson and Robert McCarley, proposed the Activation-Synthesis Theory of dreaming in the late 1970s, which considers the biological processes behind dreaming rather than psychological interpretations, i.e. the brain’s activity during sleep.

• Activation
  • The brainstem generates random electrical impulses during REM sleep.
  • These impulses activate various regions of the brain, particularly those responsible for emotions, memories and sensory experiences.
• Synthesis
  • The brain, always striving to make sense of information, attempts to synthesise these random signals into a coherent narrative, i.e. tries to make sense of them.
  • The cerebral cortex, the part of the brain involved in higher-order thinking, constructs dreams by integrating these disjointed signals into a storyline.

The theory suggests that dreams:

• Do not necessarily have inherent meaning and are largely random.
• Have a bizarre and illogical nature because of the random activation of different brain regions.
• Are a natural byproduct of the brain’s normal functioning during sleep.

It challenges Freud’s theory that dreams are deeply symbolic or reflective of unconscious desires.

We have further information on this theory in a separate article.

Information Processing Theory

This theory proposes that dreaming is a way for the brain to process, organise and consolidate information, including new knowledge, emotions and memories, collected throughout the day.

Think of it as a nightly mental spring clean; the brain chooses the new information and memories to keep and discard and how to connect the new things learned to existing knowledge. This process can help us learn, adapt and remember better.

Some proponents of this theory suggest that dreaming can aid in problem-solving. The brain continues to work on unresolved issues or puzzles from our waking life, leading to insights and solutions that might appear in our dreams.

There have been several studies on learning and memory improvement post-sleep. Here are some examples:

• Carbone & Diekelmann (2024). An update on recent advances in targeted memory reactivation during sleep – a review that aims to highlight the most recent advances of this research.
• MacDonald & Cote (2021).Contributions of post-learning REM and NREM sleep to memory retrieval – a detailed review of the scientific literature indicating beneficial effects of post-learning sleep on memory retrieval.
• Paller et al. (2022). Memory and Sleep: How Sleep Cognition Can Change the Waking Mind for the Better – suggest that changes in memory storage during sleep may shape not only what we can remember but also who we are.
• Potkin & Bunney (2012). Sleep Improves Memory: The Effect of Sleep on Long Term Memory in Early Adolescence – found that memory is significantly improved by sleep in a sample of normal adolescents.
• Staresina (2022). Sleep research: Can sleep improve our memory? – discusses research into the effects of sleep on memory consolidation.

Emotional Regulation Theory

This theory suggests that dreaming:

• Has an important role in processing our emotions, such as anxiety, fear, sadness and also joy, which we may avoid or suppress during the day.
• Helps regulate our emotions and achieve a better emotional balance, thus helping us to cope more effectively with daily challenges and stresses.
• Provides a safe space for us to experience, explore and work through our emotional states, stress or trauma without the constraints and inhibitions of waking life.
• Enables our brains to consolidate memories and connect emotional experiences to them, thus influencing our feelings about past events, usually during REM sleep.

Overall, dreaming can help us improve our understanding of our emotions and regulate them better, thus promoting good mental health, well-being and resilience. There have been many studies that have linked dreaming to mental health and resilience, and here are some examples:

• Krishnan (2021). Orchestration of dreams: a possible tool for enhancement of mental productivity and efficiency – their review “observed that dreams in distinct phases, can be directly/indirectly related to development of cognition, skill enhancements, learning, healing, and even stress management affecting overall performance and productivity of an individual”.
• Palagini et al. (2023). The connection between dreaming, the brain and mental functioning: where are we now? – provides details on current research and future topics of interest.
• Palagini & Rosenlicht (2011). Sleep, dreaming, and mental health: A review of historical and neurobiological perspectives – their review outlines the history of theories about the genesis and function of dreams and sleep and their relationship to mental illness.
• Soffer-Dudek (2020). Are Lucid Dreams Good for Us? Are We Asking the Right Question? A Call for Caution in Lucid Dream Research – discussed that lucid dreams are associated with increased mental health and self-confidence and with psychological resilience in the face of traumatic stress.

Threat Simulation Theory (TST)

This theory argues that dreams serve an evolutionary function by stimulating threatening situations or events and allowing the dreamer to rehearse responses. It suggests that stimulating threats in dreams:

• Serve an evolutionary purpose by enabling us to practice survival skills in a safe environment.
• Helps us develop better strategies and improve our responses to dangerous situations, thus increasing our chances of survival if we encounter similar threats in real life.
• Enables us to become emotionally desensitised to fear and anxiety when repeatedly exposed to threatening events in our dreams, which can promote calmness in real-life stressful situations.

Threat dreams involve events where the dreamer faces some manner of danger or threat. Here are some examples and possible interpretations:

• Being chased – one of the most common threat dreams. It often symbolises running away from something in your waking life that you find overwhelming or frightening and do not want to confront, such as a problem or a difficult situation.
• Falling – can indicate a loss of control or fear of failure. It might reflect insecurities or anxieties about an inability to handle a situation or not meeting expectations.
• Natural disasters (e.g. earthquakes, floods, hurricanes and volcanic eruptions) – might reflect feelings of instability or lack of control in your life and can indicate that you are facing significant changes or challenges.
• Teeth falling out – this is also one of the most common dreams. It can symbolise a loss of power or confidence and is often linked to anxiety, stress, or fears around ageing and even teeth grinding (Cambridgeshire Live). It might indicate feelings of vulnerability or concerns about your appearance or how others perceive you.
• Being attacked or threatened – often represents feelings of vulnerability, fear or powerlessness. They might reflect real-life situations where you feel threatened or unsafe by someone or something.
• Accidents (e.g. car or aeroplane crashes) – often reflect anxieties about safety and control. They might suggest that you are concerned about the direction your life is taking or the potential risks ahead.

Dreams have some further examples of common threat dreams.

Cultural and Historical Interpretations

Dreams have fascinated people across different cultures and time periods, each interpreting them in unique ways.

• Ancient civilisations
  • Ancient Egyptians saw dreams as messages from the gods that conveyed divine insights, warnings or guidance. Dreams were often inscribed on papyrus or discussed with priests for interpretation and prophecies. They even had dedicated dream temples where people went to sleep, hoping to receive divine insights.
  • In ancient Greece, dreams were considered divine messages or omens from the gods and were thought to provide insights into the future. They played a significant role in decision-making and healing practices.
• Medieval and Renaissance periods
  • In Medieval Europe, dreams were often viewed as omens or prophecies, with dream interpreters playing significant roles in society.
  • During the Renaissance period, dreams were linked to artistic inspiration and the subconscious mind, influencing literature and art.
• Indigenous cultures
  • Many indigenous cultures view dreams as a bridge between the spiritual and physical worlds. Dreamcatchers, for instance, are used to filter out bad dreams.
  • Native American Tribes often view dreams as a way to connect with their ancestors and the spirit world.
  • Australian Aboriginals believe dreams hold deep cultural and spiritual significance and are considered a bridge to this spiritual dimension.
• Modern perspectives
  • Sigmund Freud and Carl Jung, pioneers in modern psychology, explored dreams as windows to the unconscious mind, each offering their theories on how dreams reveal hidden desires and archetypes.
  • Modern neuroscience explores dreams as part of the brain’s activity during sleep, focusing on their roles in memory consolidation, emotional regulation and problem-solving.

Modern Scientific Approaches to Dreams

In modern times, there has been a move towards more scientific approaches to dreams, and neuroscience has played a significant role. It explores the brain’s activity during sleep, particularly during the Rapid Eye Movement (REM) phase when most vivid dreams occur. In fact, the discovery of REM sleep in the 1950s revolutionised dream research (Palagini et al. 2023).

Scientists have discovered that many areas of the brain are involved in dreaming, such as:

• The prefrontal cortex – is associated with behaviour, decision-making and executive functioning. It is less active during REM sleep, which is why dreams can be strange and are often irrational.
• Amygdala – is crucial for processing emotions. It is very active during REM sleep, which is why dreams can feel intensely emotional.
• Hippocampus – has a crucial role in forming, organising, storing and retrieving memories. Its role in dreaming is not completely understood, but it is believed it incorporates memories into our dreams.
• The thalamus – is a crucial structure located deep within the brain, acting as a central relay station for sensory information. During sleep, it helps transmit sensory and visual information to the cortex, influencing dream content.
• Brainstem – connects the brain to the spinal cord and controls many essential functions necessary for survival. It plays a crucial role in regulating sleep cycles, including the transition between different sleep stages, such as REM and non-REM sleep. It also controls the paralysis of most muscles during this phase to prevent us from acting out our dreams.
• Occipital lobe – is located at the back of the brain and is primarily responsible for processing visual information. During REM sleep, the occipital lobe is active, contributing to the vivid imagery in dreams.

These brain regions work together with one another to create rich, often surreal experiences that characterise our dreams. By understanding their roles, scientists can start unravelling the mysteries surrounding dreaming and its impact on our mental processes. They can conduct sleep studies to improve understanding of brain activity and connections.

Sleep studies, also known as polysomnography, have significantly expanded our knowledge and understanding of dreams and their mechanisms, functions and impacts on our waking lives through various tests, tools and experiments. Researchers can monitor individuals’ brain activity to understand the neural activity associated with dreaming. They can also adopt dream reporting, where participants are awakened during REM sleep and asked to report their dreams, which helps correlate specific brain activity with dream content and themes.

Technology has also revolutionised dream research, enabling scientists to explore the complexities of dreaming in ways previously impossible. Here are some examples:

• Neuroimaging – various techniques can monitor brain activity during sleep, providing insights into the neural correlates of dreaming, e.g.:
  • Functional magnetic resonance imaging (fMRI) – measures brain activity by detecting changes in blood flow. It helps identify which brain regions are active during dreaming and how different areas interact.
  • Electroencephalography (EEG) – measures and records the electrical activity within the brain by using electrodes placed on the scalp. It is particularly useful for identifying different sleep stages, including REM sleep, where most dreaming occurs.
  • Positron Emission Tomography (PET) – measures metabolic activity in the brain using radioactive tracers, helping researchers understand the biochemical processes involved in dreaming.
• Wearable devices and mobile apps – help individuals track their sleep patterns and dream occurrences. By logging dreams and sleep data, researchers can gather large datasets for analysis, leading to more comprehensive insights into dream patterns and their correlations with mental health.
• Artificial Intelligence (AI) and machine learning – AI algorithms can analyse vast amounts of dream data, identifying patterns and predicting dream content. This technology is also used in dream interpretation, helping decode dreams’ symbolism and emotional significance.
• Virtual Reality (VR) – VR technology has been used in experiments where participants control virtual environments from within their dreams. This innovative approach helps researchers study the interaction between conscious control and dream states.

While there has been a vast amount of research on dreams, there are significant challenges in studying this fascinating area due to their inherently subjective and personal nature. Dream experiences can vary significantly between people, can be influenced by various factors, such as psychology and mood, and their interpretation can vary across cultures. Individuals can also find it difficult to remember and report dreams accurately, and the process of waking up can alter or erase dream memories.

As dreaming involves complex and dynamic brain activity that is not yet fully understood, it is challenging to pinpoint specific mechanisms or causes of dreams. While technological tools have helped and expanded our understanding, they have their limitations and manipulating sleep patterns or inducing specific dream content can also raise ethical concerns.

Common Types of Dreams and Their Potential Meanings

Human experiences of dreams and their frequency, vividness and content will vary greatly. However, there are some common types or categories of dreams, for example:

• Recurring dreams – are repetitive dreams with little variation in story or theme. They often point to unresolved issues, persistent anxieties or repetitive patterns in life that require attention.
• Nightmares – frightening or disturbing dreams that can cause us to wake up feeling anxious, distressed, scared and even feelings of terror. These dreams are often linked to stress, anxiety or unresolved fears, which may indicate issues need addressing, or it could be a way of processing difficult experiences and past traumas. Frequent nightmares might also indicate underlying mental health issues, such as PTSD or anxiety disorders.
• Lucid dreams – being aware that you are dreaming while still asleep. Some people can influence and control the narrative and content of these dreams to an extent. These dreams can indicate a strong sense of self-awareness, becoming more in tune with your inner self and control over your waking life. Soffer-Dudek (2020) has further information on lucid dreams.
• Daydreams – a state of mind where you are awake, but your attention drifts away from the current task to a more relaxed or imaginative state and may involve imagining or fantasising about scenarios. Zittoun & Cabra (2023) define it as: “The process by which we partly or fully decouple from what seems to be one’s current activity in the world”. Daydreams can reflect desires, goals and unfulfilled wishes but may also indicate a desire to escape reality or current challenges.
• Prophetic dreams – some believe that dreams can predict future events. These dreams are often interpreted as spiritually significant or indicative of an intuitive connection to upcoming events. Scientific evidence supporting prophetic dreams is limited and typically seen as a coincidence.

Unanswered Questions and Ongoing Mysteries

There are still unanswered questions and ongoing mysteries surrounding dreams today, such as:

• What is the purpose of dreams? We still do not fully understand why we dream, and the purpose remains unclear despite numerous theories.
• What do dreams mean? While some believe dreams can provide insights into our subconscious, others argue that they might not have any specific meaning.
• Why do some people remember dreams vividly while others do not? While researchers have identified some factors that influence why some people remember their dreams more vividly than others, the complete picture remains elusive.
• Why do we have nightmares? Nightmares can be distressing and disruptive, but understanding their exact causes and effectively treating them is still a challenge.
• Are dreams purely biological, or do they have deeper psychological or spiritual purposes? The full picture is still unfolding, and dreams likely have multiple purposes, encompassing biological, psychological, and potentially even spiritual dimensions.
• Can we control our dreams? Lucid dreaming, where a person becomes aware they are dreaming and can control the dream, is a fascinating phenomenon, but the mechanisms behind it are not fully understood.
• Can dreams predict the future, or is this just a coincidence? Some people believe that dreams can offer glimpses into the future, but there is no scientific evidence to support this idea.
• Why do certain dreams keep recurring throughout a person’s life? Recurring dreams can be particularly puzzling. Researchers are still trying to understand why certain dreams repeat and what they might signify.

While significant strides have been made in understanding some of the mechanisms behind dreams, there are still a lot of unknowns. Dreams are deeply personal and complex experiences, and science is still working to unravel all their mysteries. Those taking a more philosophical and spiritual approach are also working towards understanding. The more we study sleep and dreaming, the closer we get to answering these intriguing questions.

There is some exciting new research on the horizon, and here are some links with further information:

• Bloxham (2024). The Conversation – an article on four breakthroughs that are changing our understanding of dreams, including research exploring the possibility of two-way communication between lucid dreamers and researchers.
• Mallett et al. (2024) – a review of recent interdisciplinary advances that have now opened up new opportunities for studying dreams.
• University of Leeds (2024) – will EEG be able to read your dreams? The future of the brain activity measure as it marks 100 years.

Conclusion

The fascination with dreams spans history, and they have captivated the imagination across different eras and cultures. Despite extensive research over centuries, there is no single, universally accepted answer to why we dream.

Several compelling theories have been proposed, such as Freud’s Psychoanalytic Theory, Activation-Synthesis Theory, Information Processing Theory, Emotional Regulation Theory and Threat Simulation Theory. While they offer valuable insights, the true purpose of dreaming remains one of the great mysteries of neuroscience and psychology.

We may dream for numerous reasons, encompassing biological, psychological, and potentially even spiritual dimensions. It is known that there are common themes to dreams, and they seem to be more vivid during REM sleep. They can also contribute to our mental and emotional well-being in various ways. However, the experience is highly variable and personal, thus making research challenging.

The interdisciplinary nature of dream research means that various perspectives are continuously being explored. While modern science provides valuable insights into the biological mechanisms of dreaming, psychological and spiritual interpretations add rich layers of meaning that science alone might not fully explain.

The full picture is still unfolding, and while we have learned a great deal, dreams remain one of the brain’s greatest enigmas. Their complexity and mystery make it a fascinating subject for study and personal reflection.