Fascinating and strange, what the mind can create seemingly right in front of your eyes. This book is all about different types of hallucinations that people experience- from many different causes. Oliver Sacks, neurologist, describes case studies of patients, as well as his own visual distubrances caused by migranes and intentional drug use (back in the 60’s and 70’s). Each chapter has a focus on the type of hallucination- some caused by illness, others by brain damage, sensory deprivation or chemical influences. I was surprised at how specific the different types of hallucinations are. For example, before the onset of a migrane many people smell certain things very distinctly. Other people see geometric patterns behind their eyes or superimposed on everything they look at. Still others see flashes of light. I can’t remember the cause of these (the book was so long and detailed) but some hallucinations make people see objects or figures either huge in size, or diminutive – little people marching around or going up and down stairs. This sounded so curious, I’d never heard of it. Sacks relates how the brain often imagines things just on the verge of sleep- and for some people this is heightened, so they are convinced they see figures standing in the room, or have strange sensations of shrinking or expansion (it’s very common but most people don’t remember it). Odd distortions of perception are also explored in the chapter about phantom limbs, and another about out-of-body experiences- both of which have biological explanations, what is going on in the brain that cases these perceptions. Including explanations of hallucinations of figures coinciding with an overwhelming sense of benevolence or euphoria, that many could interpret as a religious experience. I think what fascinates me most, is how hard the brain works to make sense out of things when there is no sensory input for it to use- so that people in solitary confinement for example, or deprived of their sight, will start seeing faces or brilliant colors. There’s also details in here that make me marvel, at how complex the mechanism of vision is, and how delicately the brain interprets it for us- and so easily it can go awry, making us see things that aren’t there (likewise smell or hear, he deals briefly with olfactory and auditory hallucinations too).
So much in this book I can’t even touch on or explain, as admittedly I struggled to understand some of it myself. Not that the author makes it hard to comprehend, but sometimes it goes so quickly through the material that I feel I missed some parts and had to backtrack. I listened to this one as an audiobook (read aloud by Dan Woren, ten hours) and certainly want to have it in hand someday on paper, to experience more thoroughly.
Borrowed from the public library.
