Share this article:
Why Do We Dream and What Does it Do to Us?
Theories of Dreaming
Several theories of dreaming address the question of why we dream.
Expanding on the early psychologically based dream theory of Sigmund Freud, modern psychological dream theories include how brain activity affects dreams (Perogamvros and Schwartz, 2012 and Ruby, 2011).
Cognitive theories of dreaming state that dreams come about as a normal cognitive process, independent of an individual’s psychological needs. For example, dreams become more complex as our cognitive abilities mature, as evidenced by the more simple dreams of young children compared to the older children and adults (Domhoff, 2003 and Domhoff, 2001).
The Continuity Theory states that continuity exists between our waking life experiences, or issues, and our dreams (Schredl and Hofmann, 2003, Schredl and Reinhard, 2009–2010 and Domhoff, 2010). While many researchers agree there is continuity between our dreams and waking life preoccupations, others emphasize the importance of exploring the differences (Hobson and Schredl, 2011). For example, people who have had limbs amputated still dream as if they had their missing limbs. Paraplegics, for example, did not dream that they were unable to move (Voss et al., 2011 and Saurat et al., 2011). This indicates that the continuity between wake and dream experiences is not straightforward. Genetically encoded movement patterns may account for some of the content of our dreams.
Brain-based theories of dreaming combine the subjective experience of dreaming with objective measurements of brain chemistry and neural activity (Nir and Tononi, 2010 and Schwartz et al., 2005). One of the hallmark brain-based theories of dreaming was the Reciprocal Interaction and Activation Synthesis Theory (Hobson and McCarley, 1977). The theory postulated that the firing of neurons housed in the brainstem during REM activates the chemically altered brain, accounting for the common properties of dreams. These include uncertainty in place, person and era; the incongruity and discontinuity in the story line; and delusional acceptance of the dream as real.
This theory expanded into the Activation, Input–Output, Modulation (AIM) model that emphasized the importance of brain activation, input–output gating, and chemical modulation to explain the common properties of dreams (Hobson et al., 2000). Brain activation, the A in AIM, is necessary for dreaming to be initiated. Input, the I in AIM, is mostly from the internal sources, and the M in AIM accounts for changed brain chemical modulation. The AIM model and Activation Synthesis Theory did not hypothesize how the neural activation of forebrain neurons actually produces dreams.
The Self-Organization Theory of dreaming hypothesized that a dream emerged when forebrain neural activity self-organized (Kahn and Hobson, 1993, Kahn et al., 2002 and Kahn et al., 2000). The dream is created as individual memories, thoughts, and feelings self-organize without direction from the executive portion of the brain. Since there is no central control, the dream comes together with little regard to logic. This undirected process provides the dreamer with unexpected experiences.
A theory that directly postulates a function for dreaming is the Threat Simulation Theory (Revensuo, 2003 and Valli et al., 2005). Dreams have evolved to prepare for the life’s challenges by serving to simulate the threatening events in waking life. Being exposed to, and dealing with these threats when asleep helps prepare the dreamer for similar situations when awake. The theory argues that current dreams of threatening events are evolutionary carryovers from threats our ancestors encountered everyday, such as being chased by large animals, fleeing from enemies, and dealing with natural disasters.
Protoconsciousness Theory directly postulates a function for the REM stage of sleep in that REM is necessary for consciousness to develop (Hobson, 2009). While perception and emotion exist in a protoconscious state, self-reflective awareness does not. The theory postulates that brain activation in REM sleep provides a virtual model of the world from which consciousness and self-reflective awareness will develop. The brain activation occurring in REM is necessary for brain maturation before external activation becomes substantial.
Hobson (2009) states “REM sleep dreaming can be viewed as a virtual reality pattern generator used by the brain to instantiate and maintain its readiness for adaptive interaction with the world. REM sleep dreaming is as much a preparation for waking consciousness as a reaction to it.”
What Dreaming Does for Us
The benefits of dreaming are currently being explored. There is some research that shows dream content contributes to improved performance on a learning task (Stickgold et al., 2001, Payne and Nadell, 2004, Wamsley and Stickgold, 2010 and Desseilles et al., 2011). Research has also shown that sleep enhances the consolidation of memories (Diekelmann and Born, 2010, Wilhelm et al., 2011, Smith, 1995 and Walker, 2005), creativity, and problem solving (Maquet and Ruby, 2004, Barrett, 2007 and Barrett, 1993), and helps with the learning of new material, including the ability to solve problems such as finding a solution to an anagram puzzle (Walker et al., 2002a, Walker et al., 2002b and Walker et al., 2003). REM sleep has been shown to improve performance on a remote association task that requires insight to see connections between concepts (Caiet al., 2009).
Aside from the benefits of sleep-enhanced learning and memory consolidation, benefits of dreaming also occur on at psychological and emotional levels. Studies have shown that emotion regulation occurs in REM sleep. For example, negative emotions are reduced during REM. Taking the two together, improved memory consolidation and emotion regulation, we sleep both to remember and to forget (Walker and Van der Helm, 2009).
Other research emphasizes the ability of dreams to help heal emotional wounds such as the trauma of divorce or loss of loved ones (Cartwright et al., 1998a and Cartwright et al., 1998b). Furthermore, dreams may help find resolutions to difficult issues by making connections while asleep in a safe environment (Hartmann, 2010 and Hartmann, 2008).
Encyclopedia of Mental Health, Second Edition, tackles the subject of mental health, arguably one of the biggest issues facing modern society. The book presents a comprehensive overview of the many genetic, neurological, social, and psychological factors that affect mental health, also describing the impact of mental health on the individual and society, and illustrating the factors that aid positive mental health.
The book contains 245 peer-reviewed articles written by more than 250 expert authors and provides essential material on assessment, theories of personality, specific disorders, therapies, forensic issues, ethics, and cross-cultural and sociological aspects. Both professionals and libraries will find this timely work indispensable.
Researchers and clinicians in psychology work across a vast array of sub-disciplines, including applied psychology, addictions, cognitive psychology, developmental and educational psychology, experimental physiological psychology, forensic psychology, neuropsychology, and behavioral and cognitive therapy. For these professionals, and students as well, cross-disciplinary study is a given. For more than 75 years, Elsevier has cultivated portfolios of psychology books, eBooks, and journals covering current and critical issues in all of these areas. This vital content provides a sound basis of understanding for all those involved in this multi-faceted field.