The key ideas

Making Up the Mind: How the Brain Creates Our Mental World

Chris Frith, 2007

The world seems to simply lie there in front of our eyes. Neuroscientist Chris Frith shows that the brain builds a model of it, guesses what comes next and hides all of that work from us. This book explains why knowing about an illusion does not make it go away, why you cannot tickle yourself, and how the same guessing machine helps you understand other people.

Who it is for

For anyone who has ever doubted their own eyes and wants to know where illusions, hunches and the feeling of "I am doing this" come from. No knowledge of the brain needed.

Our perception of the world is a fantasy that coincides with reality.

What the book is about

At a party, Chris Frith explains what he does for a living, and the woman he is talking to says, with disappointment, "Oh, so you're a psychologist!" A professor of English is sure that by studying the mind with scientific methods, he is killing what is human in us. Frith answers these complaints with a whole book, and the professor argues with him to the very last page.

Frith is a British neuroscientist who studies how the work of the brain turns into sensations and thoughts. His central idea sounds strange: we do not see the world directly. The brain builds a model of the world, guesses what will happen next, checks the guess against the signals from the senses, and hides all of this work from us. That is why the world seems to simply lie there in front of our eyes.

Ahead of you: an illusion you cannot stop seeing, the reason you cannot tickle yourself, and how the same guessing machine helps you understand other people.

Idea 1. The brain knows more than it tells us

A woman suffered carbon monoxide poisoning, and it damaged the part of her visual system that handles the shape of objects. She cannot say whether a stick in front of her is upright or at an angle. But when she is asked to pick it up, her hand turns in advance to exactly the right angle.

Her brain "knows" how the stick lies, but she herself does not. Frith puts it this way: the brain knows, but it does not tell us.

This shows even more vividly in a condition called blindsight. A person's primary visual cortex, the main entry point for signals from the eyes, is damaged, and they are blind in part of their field of vision. Lawrence Weiskrantz was the first to describe such people in detail. A bright spot moved in the blind area, and the person was asked to guess which way it was going. The person said they saw nothing. Yet they guessed right more than 80% of the time.

What this means for you: if you see nothing, that does not mean your brain saw nothing.

You are walking down the pavement, your mind busy with yesterday's conversation. Your foot steps aside on its own, and only then do you notice the puddle. It was not your conscious mind that decided to go around it, but the part of your brain that was watching the road the whole time.

Consciousness receives only a small part of what the brain processes. Much of what we do right, we do without its knowledge.

Read in Livria

About the author

Chris Frith is a British neuroscientist, emeritus professor at University College London and a Fellow of the Royal Society. For many years he used brain scanners to study how the brain works, including in people with schizophrenia.

All books by this author: Chris Frith

Terms from the book

  • Scanner
  • Rizzolatti
  • Mirror neurons
  • Blakemore
  • Bayes
  • Neuroscientist
  • Helmholtz
  • Schizophrenia
  • Johansson
  • Primary visual cortex: An area of the cortex at the back of the brain where the signal from the eyes arrives first. When it is damaged, a person goes blind in part of their field of vision.
  • Blindsight: A condition in which a person with a damaged visual cortex says they see nothing in the blind area, yet correctly guesses what is happening there.
  • Weiskrantz: Lawrence Weiskrantz, a British psychologist at Oxford. He was the first to describe blindsight in detail.
  • Hering: Ewald Hering, a nineteenth-century German physiologist. He gave his name to an illusion in which straight lines over a background of radiating rays look curved.
  • Unconscious inferences: Helmholtz's idea: the brain draws conclusions about the world from the signals of the senses, and we see only the result of those conclusions, never noticing them being drawn.
  • Ames: Adelbert Ames Jr., an American vision researcher. In 1946 he built a distorted room that looks ordinary, and people inside it seem to be of different heights.
  • Change blindness: Failing to notice even a large change in a picture when you do not know in advance where to look.
  • Prior knowledge: The expectation the brain already has before new signals arrive. In Frith's model, every act of perception starts from it.
  • Prediction error: The difference between what the brain expected to sense and what actually came in from the senses. The brain uses this difference to correct its model of the world.
  • Blind spot: The place on the retina where the optic nerve leaves the eye and there are no light-sensitive cells. The brain fills in the gap in the picture by itself.
  • Libet: Benjamin Libet, an American neurophysiologist. In 1983 he compared the moment of a conscious wish to move a finger with the moment brain activity changes.
  • Wolpert: Daniel Wolpert, a British scientist who studies how the brain controls movement and predicts its consequences.
  • Sense of agency: The feeling that I am the one performing an action and that its consequences are caused by me.
  • Delusions of control: A firm belief that your movements or thoughts are being controlled by an outside force. Found in schizophrenia.
  • Hallucination: Perceiving something that is not there: a voice, an image or a sound that, for the person, cannot be told apart from the real thing.

All terms

Similar books