Do you dream? Do you know why you dream? What even are dreams? Dr Rosie Gibson, Senior Lecturer at the Sleep/Wake Research Centre, Massey University dives into the surreal worlds that we inhabit while we sleep.

Dreaming is an experience that many of us can relate to. An understanding of dreaming has relied on self-reports in order to document and define typical contents or scenarios. This has allowed an exploration into how dreams can differ or change within and between people providing a foundation for spiritual and psychological theories of dreaming. Modern neurological research adds evidence concerning the function of dreams and how they support waking life.

The dream experience

The dream experience has some common features which differ from waking^[1]. When considering sensation, dreams are often visual, contain audible sound and sensations of movement, and can be highly emotive whilst conversely lacking in sensations of smell, taste, and pain. The movement of characters can be continuous as well as shifting. Physical laws and spaces can be abnormal. Scenarios are often bizarre, and time frames can be unstable. People and places have the ability to metamorphosise into others, inexplicably appear, or fade away.

Furthermore, we typically lack thoughtful insight during our dream experience. Plot features can shift quite radically and suddenly without explanation. However, dream scenarios and their shifting behaviour are typically accepted by the dreamer and it often feels as though they are somehow linked. Our social judgement is often altered, therefore the choices and assumptions we make as a dream character do not always reflect those of our waking selves.

Research has compared reported dream content between ages, exposures, and health status^[2]. Such differences indicate that dreaming is a life experience and part of who we are whether in a spiritual sense, psychological, or as physiological by-product of our processing brain. By documenting and sharing dream experiences we are able to identify times of unusual dreams, for example frightening reoccurring nightmares, or dreams of heightened lucidity^[3]. Such documentation subsequently strengthens the relationship between our dreaming and waking lives.

The function of dreams

The function of dreams has been an area of interest for centuries. Dreams were traditionally interpreted as spiritual and meaningful in nature and frequently used therapeutically^[4]. For example, ancient Egyptians believed that the Gods communicated through dreams. Dreams have also been proposed to provide a simulated opportunity to rehearse real-life waking events or problem solve^[5]. And early psychoanalysts, such as Sigmund Freud and Carl Jung, believed that dreams had latent content and symbols concerning wish fulfilment or the collective unconscious and therefore took place in the safe space of sleep.

Rapid eye movement

In the mid 1950s, the science of sleep and dreaming was greatly impacted by research finding a high correlation between the presence of rapid eye movement (REM) and dream activity.

This provided evidence of a relationship between objective neurological changes of the brain with the subjective experiences of the mind. Theories such as Hobson’s Activation Synthesis Model^[6] state that the properties of the dream (e.g. visual perception, bizarre scenarios, and intense emotion) are the consequence of changes within the brain’s physiology and therefore more as meaningless side-effects of the brain’s offline processing occurring during sleep.

Recall is therefore only facilitated when the frontal cortex and the neurotransmitters associated with making sense and memories and experiences are reactivated on waking and synthesised into a dream narrative that can be shared.

Neurological research

Modern neurological research also provides alternate explanations for the substance of dream experiences. For example, during REM sleep the brainstem is limited in its ability to receive and respond to external stimuli. Instead, it spontaneously activates itself and signals conveying sensory information are generated. This activates channels within the brain that we use when awake therefore creating the perception of experience.

This is particularly evident with activity from the eyes and visual cortex internally creating and processing random visual information as well as the reactivation of the limbic system, an area of the brain associated with emotions and sensations, as well as triggering of memories.

The neurological study of dreaming has led to a raft of work exploring their function. With evidence supporting the notion that dream processes play an important role in learning^[7] and the consolidation of memories, emotional regulation^[8], and the neural cleansing^[9] of the brain important for mental health.

Footnotes

1. Kendra Cherry, 5 Major Characteristics of Dreams (Very Well Mind, 2020)
2. Piroska Sándor, Sára Szakadát, and Róbert Bódizs, Ontogeny of dreaming: a review of empirical studies (National Library of Medicine, 2014)
3. Stephen Laberge: Lucid Dreaming (excerpt) — A Thinking Allowed DVD w/ Jeffrey Mishlove (YouTube, 2010)
4. Drew Dawson, Explainer: what is dreaming? (The Conversation, 2012)
5. Antti Revonsuo, Jarno Tuominen, and Katja Valli, The Avatars in the Machine: Dreaming as a Simulation of Social Reality (Open MIND, 2015)
6. J. Allan Hobson and Edward F. Pace-Schott, The cognitive neuroscience of sleep: neuronal systems, consciousness and learning (Nature Reviews Neuroscience, 2002)
7. Sleep, Learning, and Memory (Division of Sleep Medicine at Harvard Medical School, 2007)
8. Serena Scarpelli, Chiara Bartolacci, Aurora D’Atri, Maurizio Gorgoni, and Luigi De Gennaro, The Functional Role of Dreaming in Emotional Processes (Frontiers in Psychology, 2019)
9. Matthew Walker, Why your brain needs to dream (Greater Good Magazine, 2017)

Fall into the dream worlds of Salvador Dalí, René Magritte, Marcel Duchamp, Leonora Carrington, and Man Ray at Surrealist Art: Masterpieces from Museum Boijmans Van Beuningen (at Toi Art at Te Papa until 31 Oct).