Beyond Threat Simulation

Beyond Threat Simulation
While Revonsuo (2000) limits his argument to the effectiveness of dreams in preparing for real-world threats, it is our goal now to extend this argument. We propose that the fitness-enhancing benefits of dreaming is not restricted to threat rehearsal, and the evolution of other higher-order cognitive faculties has been strongly influenced by a dreaming mechanism. By commenting on other fitness-enhancing aspects of the phenomenology of dreaming, besides threat, it also becomes possible to integrate our theory with portions of Hobson and McCarley’s (1977) activation-synthesis hypothesis, with particular regards to their view on the random information that leads to dreaming.
While dream content is not completely random, as demonstrated by the fact that there tends to be an over-representation of negative affect (Hall and Van de Castle, 1966; Merrit et al., 1994)) and social interactions (Kahn et al., 2002), there still is a great deal of variability and randomness observed in dream content. We argue that this variability is likely due to activation propagated from the brainstem, and that this noise in the system is beneficial. The advantages of having noise as a crucial factor in a dream-generation mechanism could be likened to the benefits of genotypic variability in the evolution of species (cf., Darwin, 1995). Given an unpredictable and variable environment, variability in traits increases the possibility that a certain trait will randomly confer an advantage under certain circumstances, this being the crux of Darwin’s theory of natural selection. In dreams, the potential advantage of noise and variability in the system allows for a broad range of scenarios to be simulated and new scenarios to be created rather than having the same type of dream occur repeatedly. This concept relates to ideas discussed by Kahn, Combs, and Krippner (2002), in terms of stochastic resonance which they contend prevents mental activity from perseverating, which allows for novel situations to be developed through the presence of noise in the system.
Aside from our theory being in a state of consonance with theories of both activation-synthesis and threat-simulation, we also contend that increased fitness is not limited to situations of threat rehearsal and that the information processing occurring in dreams should be similarly represented in the brain as is waking cognition. This is the case because if sleeping and waking cognition are quite different, then rehearsing threatening situations in a dream may not transfer into the ability to better handle similar situations in waking life. However, evidence from lucid dream studies (described below) indicate that tasks such as counting and singing during a dream, which should activate the left and right hemispheres, respectively, do just that. When a person is singing in a dream, their right hemisphere is more active, and conversely when a person counts, the left hemisphere becomes more activated (LaBerge and Dement, 1982). A more recent PET study demonstrated that subjects trained on a serial reaction time task showed task-related increases in brain activity during REM sleep which was correlated with improved performance on the task after sleep (Maquet et al., 2000).
Also, from a neuropsychological perspective, evidence comparing bizarre dream cognition with certain psychopathology indicates another link between brain activity in dreams and waking. For example, people who suffer from damage to frontal and temporal brain areas typically report the misidentification of faces during waking life, a condition known as Fregoli syndrome. Some research has indicated that a decrease of activity in these regions, reported from neuroimaging studies in sleep, correspond to similar reports of misidentification during dreaming (Schwartz and Maquet, 2002). So, the functional architecture of our brains similarly influences both sleep and waking cognition and perception, supporting the idea that
neurophysiological correlates of cognition appear stable across the two forms of consciousness.