David Eagleman and Don Vaughn’s ‘defensive activation theory’: highly original and creative, but is it convincing?
‘Here’s Eagleman and Vaughn’s theory in nutshell: the role of dreams is to ensure that the brain’s visual cortex is stimulated during sleep. Otherwise, if the visual system were deprived of input all night long, the visual cortex’s function might degrade….’
— Neuroskeptic, via Discover Magazine
The question for me is the basis for their assumption that visual cortical function would rapidly degrade without stimulation, as well as the notion that what happens in REM (dreaming) sleep is primarily stimulation of the visual cortex. As much as a visual experience, I have long thought of dreaming as a captivating emotional experience. I have wondered if the main purpose of dreaming might be to provide a compelling attraction to keep us asleep so that we would not miss out on the other benefits of sleep. This is experience-near — except for nightmares, which are a perversion of the process and tend to awaken us — most people when awakening from a dream try to get back to it, loathe to give it up. Given the survival value of not being caught vulnerable and asleep, we would have evolved to need less sleep if it was possible, if there were not a good reason to sleep as much as we do. And there would have to be a strong mechanism to keep us asleep and counter the attractiveness of awakening.