Consciousness and Cognition

It is a proposal both magnetic and unlikely: Can we really engineer dreams, these internal worlds that feel so fundamentally out of our control? The incubation of specific dream content has fascinated people for millennia, from Ancient Egyptian spiritual practices to contemporary treatments for posttraumatic nightmares, yet reliable techniques have proven elusive. This Special Issue outlines a series of novel technological protocols designed to test the degree to which we can direct dream content, and to reveal the ways in which nightly dreams contribute to waking cognition. For quite a while, the sleeping brain was thought of as a light switch turned off. Benefits from a night of sleep were considered passive: a product of a lack of sensory interference during sleep (Jenkins & Dallenbach, 1924). It is only in the last half-century, after Eugene Aserinsky placed electrodes on his sleeping 8-year-old son and saw separate, identifiable stages of REM and non-REM (NREM) sleep, that researchers began testing whether specific aspects of sleep physiology enable the cognitive and emotional benefits we get from a night in bed (Aserinsky & Kleitman 1953; Walker, 2009). There has been a veritable explosion in the sleep neuroscience field since, and much of it reveals a crucial contribution of sleep in daytime functioning, from emotional stability to creative output and memory encoding (Walker, 2009). The brain, it turns out, is not passive during sleep, just differently active than wake. And this whirring of activity is not just ongoing in the sleeping brain, it is experienced in the sleeping mind, active in dreams even as we lie still and silent. Overnight while we dream we are remade, soothed by adaptation to stress (Wassing et al., 2019) and molded by consolidation of memory (Spencer, Walker & Stickgold, 2017). There is some scientific support suggesting that our nightly dreams can be a source of overnight therapy (Cartwright, 1991), memory strengthening (Wamsley et al., 2010), or even creative inspiration (Barrett, 2017)—yet more experiments and more induction protocols are needed to explore the benefits of dreams in depth. Without reliable ways to control dream content, the study of the active role of dreams in conferring sleep-related benefits has been largely stagnant. In fact, a leading theory maintains that dreams are the result of random neural firing, unimportant for learning or task benefits (Hobson & McCarley 1977; Fosse et al., 2003). This dismissal of dreams is reminiscent of the earlier notion of sleep as passive, rather than active; many attribute the benefits of sleep only to the brain state in which dreaming happens, as opposed to the dream itself. And the vast majority of sleep studies that assess changes in cognition before and after sleep do not collect dream reports, choosing to overlook mental experience in the intervening period. It seems the cognitive revolution, which has brought neuroscience back from behaviorism and rekindled the ambition to understand the mind, has somehow skipped over much of sleep science. The primary roadblock in forming a scientific understanding of the dreaming mind is that while dream reports can be reliably elicited via targeted awakenings, the content of dreams remains largely beyond our control. The logic is simple: If we cannot control dream content, then we cannot do controlled experimentation on dream content (Nir & Tononi, 2010). Control and capture of dream content has been an object of fascination in popular culture and brain and behavioral sciences for decades. To this end, sleep laboratory techniques have been developed with the goal of manipulating dream content across sleep onset, NREM and REM sleep: These range from influencing dream content with pleasant or unpleasant smells, inflating a pressure cuff on a sleeper’s leg, playing a video game prior to sleep, or inducing lucid dreams with light stimulation (Goodenough et al., 1975; LaBerge & Levitan, 1995; Sauvageau, Nielsen, & Montplaisir 1998; Stickgold et al., 2000). Our renewed interest in dream engineering aims to expand on and improve protocols that enable the direction of dream content. With this vision, we can eventually investigate and even actively drive sleep and dream functions, rather than passively assess potential dream-related benefits such as creative insight or emotional healing following sleep. The innovative dream engineering collection presented here includes new applications of technologies for dream content incubation, novel protocols for lucid dream induction, and finally the case of lucid dreaming as a viable avenue for dream experimentation: