Hallucinations Book Summary - Hallucinations Book explained in key points
Listen to the Intro

Hallucinations summary

Oliver Sacks

What hallucinations tell us about the organization and structure of our brains

4.3 (16 ratings)
15 mins
Table of Contents

    summarized in 8 key ideas

    Audio & text in the Blinkist app
    Key idea 1 of 8

    Visual hallucinations can be caused by blindness, impaired sight or sensory deprivation.

    Have you ever seen, smelled, heard, or felt something, only to realize it was your imagination? Hallucinations are perceptions that occur without a corresponding external reality. In other words, you hallucinate when you involuntarily sense something that's not really there.

    People who become blind, or whose sight is otherwise impaired, often experience visual hallucinations. In fact, one study showed that out of nearly 600 elderly people with visual problems, about 90 percent experienced some form of hallucinations. Fifteen percent experienced complex hallucinations, where they “saw” things like people, animals or entire scenes. Eighty percent had simple hallucinations, meaning they saw shapes, colors and sometimes patterns.

    When a person with partial or severe blindness experiences visual hallucinations, it's called the Charles Bonnet Syndrome (CBS). Charles Bonnet, a Genevan naturalist, first described it in 1760. He observed it in his grandfather, and later, in himself.

    Oliver Sacks once had a blind patient named Rosalie who had complex CBS hallucinations that played before her like a movie. She saw highly realistic people wearing colorful Eastern dress, and they walked in and out of the scene before her without addressing her in any way.

    One reason blind or partially blind people experience hallucinations like this is that the hallucinations spring from the same areas of the brain as visual perception. That means they're physiologically distinct from the images we create when we deliberately imagine something.

    Sensory deprivation can also cause visual hallucinations. For example, people hallucinate when they're exposed to the same monotonous scene, like darkness, for a prolonged period of time. This is often called the prisoner's cinema.

    The prisoner's cinema is so powerful that all people seem to experience it eventually after some period of isolation. Visions can range from simple geometric patterns to complex scenes, because of the increasing excitability of the visual cortex.

    Want to see all full key ideas from Hallucinations?

    Key ideas in Hallucinations

    More knowledge in less time
    Read or listen
    Read or listen
    Get the key ideas from nonfiction bestsellers in minutes, not hours.
    Find your next read
    Find your next read
    Get book lists curated by experts and personalized recommendations.
    Shortcasts New
    We’ve teamed up with podcast creators to bring you key insights from podcasts.

    What is Hallucinations about?

    This book explores the complex realm of hallucinations, and explains how they happen not only to people who are ill, but also to those who are completely healthy. Drawing on various studies, patient cases and the author’s own experiences, it describes the different causes and types of hallucinations, and shows that they're actually a common phenomenon that manifest in a variety of ways.

    Best quote from Hallucinations

    Though she had not seen anything at all for several years, she was now seeing things, right in front of her.

    —Oliver Sacks
    example alt text

    Who should read Hallucinations?

    • Anyone interested in psychology
    • Anyone who's ever seen, heard, smelt or felt something that wasn't there
    • Anyone who wants to understand the science and neurology behind hallucinations

    About the Author

    Oliver Sacks is a world-renowned neurologist, writer and professor at the New York University School of Medicine. He's written several successful books, including Musicophilia: Tales of Music and the Brain and The Man Who Mistook His Wife for a Hat. His book Awakenings was adopted into an Academy Award-nominated film.

    Categories with Hallucinations

    Books like Hallucinations

    People ❤️ Blinkist
    Sven O.

    It's highly addictive to get core insights on personally relevant topics without repetition or triviality. Added to that the apps ability to suggest kindred interests opens up a foundation of knowledge.

    Thi Viet Quynh N.

    Great app. Good selection of book summaries you can read or listen to while commuting. Instead of scrolling through your social media news feed, this is a much better way to spend your spare time in my opinion.

    Jonathan A.

    Life changing. The concept of being able to grasp a book's main point in such a short time truly opens multiple opportunities to grow every area of your life at a faster rate.

    Renee D.

    Great app. Addicting. Perfect for wait times, morning coffee, evening before bed. Extremely well written, thorough, easy to use.

    People also liked

    Start growing with Blinkist now
    26 Million
    Downloads on all platforms
    4.7 Stars
    Average ratings on iOS and Google Play
    Of Blinkist members create a better reading habit*
    *Based on survey data from Blinkist customers
    Powerful ideas from top nonfiction

    Try Blinkist to get the key ideas from 5,500+ bestselling nonfiction titles and podcasts. Listen or read in just 15 minutes.

    Start your free trial