Introducing Mind and Brain E-Book

Angus Gellatly

• Herausgeber: Icon Books
• Kategorie: Geisteswissenschaft
• Serie: Graphic Guides
• Sprache: Englisch

Seitenzahl: 109

Veröffentlichungsjahr: 2018

Beschreibung

How do emotions affect your basic decision making? Why do certain smells prompt long-forgotten memories, and what makes us suddenly self-conscious? How does the biological organ, the brain, give rise to all of the thoughts in your head – enable you to think, to feel, to be conscious and aware – to have 'a mind'? Introducing Mind and Brain explains what the sciences have to say about planning and action, language, memory, attention, emotions and vision. It traces the historical development of ideas about the brain and its function from antiquity to the age of neuro-imaging. Clearly explained by Professor of Psychology Angus Gellatly and award-winning artist Oscar Zarate, they invite you to take a fresh look at the nature of mind, consciousness and personal identity.

Leseprobe

Published by Icon Books Ltd, Omnibus Business Centre, 39–41 North Road, London N7 9DPEmail: [email protected]

ISBN: 978-178578-314-2

Text copyright © 1998 Angus GellatlyIllustrations copyright © 2013 Icon Books Ltd

The author and illustrator have asserted their moral rights

Originating editor: Richard Appignanesi

No part of this book may be reproduced in any form, or by any means, without prior permission in writing from the publisher.

Contents

Cover

Title Page

Copyright

Mind and Brain: a Brief History

Inventing the Mind

What is the Mind?

Meet the Brain

Matter or Spirit?

Pioneer Map-Makers

The Mind of the Gaps

Ventricles, Tissues and the Mind

A Fish Called Wondercure

Bumps on the Head

The Beginning of Localization

Beginning to Assemble Brain Functions

Tracing the Progress

Neurons and Glia

Grey and White Matters

The Electric Brain

Abnormal Firing

The Chemical Brian

Chemical Malfunctions

Brain, Hormones and Body

The Geography of the Human Brain

Evolution and Development

The Hindbrain

The Midbrain

The Forebrain

Left and Right Hemispheres (LH and RH)

Mental Abilities

Simple Minds 1: the Sea Slug

Simple Minds 2: Frogs and Toads

Simple Minds 3: Birds

Simple Minds 4: Human Beings

Complex Minds and Computers

Language and the Brain

Disorders of Language: the Aphasias

A Model of Language Use

Language and All the Brain

Language, Interpretation and Action

Movement and Mind

Tuning the Movements

Two Motor Movement Control System

Levels of Control of Movement

The Motor System

Damage to the Motor System

The Origins of Voluntary Movement

Proprioception and Body Ego

Smells and Emotions

Emotional Reaction

The Anatomy of Fear

Fearful Symmetry

Sub-cortical Learning

Knowing When to be Afraid

Emotions “Left and Right”

Emotional Tone

Emotion and Reason

Emotions Involved in Decisions

Memory Makes You Flexible

What Amnesia tells us about Mind

Two Kinds of Memory

Memory with and without Emotions

The Location of Memories

The Complexity of Memory

Sensing and Seeing

The Anatomy of Vision

Visual Areas: Colours, Directions and Shapes

Loss of Colour

Motion Blindness

Higher Level Vision

The Lower Visual Pathway: Effects of Injury on Recognition

A Recognition Test

The Middle Visual Pathway: Relative Spatial Positions

The Upper Visual Pathway: Effects of Parietal Damage

Mind Spaces

Visual, Motor and Imaginai Spaces

Representations of Space

Attention and the Mind

Experiments with Attention

The Attentional Network

Mental Grasp

What is Consciousness?

Blindsight

Working Memory

The Central Executive in Area 46

Narrative Consciousness

Free Will and the Frontal Lobes

Responsive Movements

Effects of Frontal Lobe Damage

FL Damage and Unwanted Responses

What is Free Will?

The Self

Loss of Self

Denial of Loss

Dissolution of Self

Feelings of Transcendence

Alternative Perceptions

Sanity: Beliefs and Pathologies

Explaining Delusions

Hearing Voices

The Impostors Delusion

What Do We Learn About the Mind from Studying the Brain?

Evolution of the Mind

The Social Intellect

Mind Reading

Do Mental States Exist Outside Our Experience of Them?

The Heider Experiment

What About Personal Responsibility?

Crime and Punishment

Further Reading

The Authors

Acknowledgements

Index

This book is about a biological organ, the brain, and what it does, the mind.

As with all body parts, evolution has adapted brains to suit particular environments and ways of life. If the brain has evolved, and is the vehicle of the mind, does it follow that the mind has also evolved? The answer to this question must be both “Yes” and “No”. The brain and “biological mind” of primates evolved for life in the jungle or out on the savannah. They are adapted to solve the particular problems of finding food and shelter, of reproducing and caring for young.

However, in addition to being an evolved “biological mind”, the human mind is also a “cultural mind” socialized in how to solve a host of “unnatural” problems thrown up by the invention of music-making and reading, painting, computer-programming and voting in elections. The cultural mind is reflexive – it reflects upon itself. To an extent, the mind is how we talk and think about it.

Mind and Brain: a Brief History

Human beings have known about the brain for a long time without being at all clear exactly what it is for. The large number of early hominid skulls which show signs of deliberate damage suggest that by three million years ago our predecessors had at least worked out that the brain is a vital organ.

The opening scene from Stanley Kubrick’s sci-fi film classic, 2001 (1968), depicts our hominid ancestors discovering homicide.

A better-intentioned knowledge was in evidence by 10,000 years ago. Neolithic skulls from around the world exhibit holes trepanned – that is, scraped or drilled – in them. The holes jj have smooth edges and show H clear signs of healing.

IT IS LIKELY THAT TREPANNING WAS A TREATMENT FOR HEADACHES, CONVULSIONS AND INSANITY – OR “SPIRIT POSSESSION”.

Trepanning was practised until relatively recent times in Europe, and continues in many cultures. Theoretical arguments for the modern technique of electro-convulsive therapy (ECT) are scarcely stronger than those for trepanning.

When Neolithic “doctors” trepanned a “patient”, did they believe they were treating the body, the mind, the spirit or the soul? We can never know. But they probably would not have recognized these distinctions.

Inventing the Mind

The epic poems of Homer in the 8th century B.C. are Europe’s earliest substantial pieces of writing. The Iliad recounts the Siege of Troy and the Odyssey tells of the journey home from Troy of the hero Odysseus (Ulysses to the Romans).

Amazingly, these works scarcely refer to what we would call “The Mind”. Homer’s vocabulary does not include mental terms such as “think”, “decide”, “believe”, “doubt” or “desire”. The characters in the stories do not decide to do anything. They have no free will.

WE ACT ONLY BECAUSE INSTRUCTED BY VOICES OR DRIVEN BY AN INNER TENSION. OR COERCED IN SOME WAY BY A GOD

Where we would refer to thinking or pondering, Homer’s people refer to speaking to or hearing from their own organs: “I told my heart”, or “my heart told me”. Feelings and emotions are also described in this half-strange, half-familiar manner. Feelings are always located in some part of the body, often the midriff. A sharp intake of breath, the palpitating of the heart, or the uttering of cries is a feeling. A feeling is not some inner thing separate from its bodily manifestation.

The Iliad and Odyssey are written versions of “songs” originally sung by non-literate bards that expressed the beliefs and ideas of their oral culture.

WE INVENTED THE MIND AS OUR ORAL CULTURE GRADUALLY TRANSFORMED INTO A LITERATE CULTURE.

People in oral cultures do not explicitly recognize the difference between a thought and the words which express it. What you say is what you intend. Your word (not your signature) is your bond. Speech is gone the moment it is uttered. Written records, by contrast, stay fixed. You can study them at leisure. This encourages a distinction between the persisting symbols on the page and the ideas they represent. “Literal” meaning gets consistently discriminated from “intended” meaning (as in the “letter” and the “spirit” of the law).

IDEAS AND THE WORDS WHICH EXPRESS THEM ARE NO LONGER ONE AND THE SAME. WRITING AND SPEECH ARE NOW ACTIONS EXPRESSING PRE-EXISTING THOUGHTS.

The ratio of rational thought branches off from the oratio of speech to become a separate concept. People’s actions express their thoughts and decisions they have made.

Literacy, it is argued, drives a wedge between two worlds. One is the world we hear and see, the world of talk and action. The other is the imperceptible mental world of thoughts, intentions and desires. Just as talk and action take place within the physical world, so literate Greeks at the time of Plato and Aristotle created a space in which to house thoughts, intentions and desires. This metaphorical space was first called the psyche, but now is known as the mind.

JUST AS THE BODY AND LIMBS EXECUTE PHYSICAL ACTIONS, SO A NEW ENTITY WAS NEEDED TO EXECUTE MENTAL ACTIONS. THIS WAS THE EGO OR SELF.

What is the Mind?

We can see that this question has no simple answer. Efforts to understand the relationship between brain and behaviour, or mind and brain, are really investigations of what these words ought to mean. Some brain functions – for example, control of body temperature – happen completely unconsciously. Other functions are usually unconscious but not always: for example, breathing, except when you voluntarily hold your breath. These might be called bodily rather than mental functions, but the distinction is not sharp.

WHEN YOU RECOGNISE AN OBJECT, YOU BECOME CONSCIOUS OF WHAT IT IS – A BOOK, SAY. BUT YOU ARE NOT CONSCIOUS OF HOW YOU RECOGNIZE IT. IN CONSCIOUSLY RECALLING SOMEONE’S NAME YOU ARE NOT OFTEN AWARE OF THE PROCESSES BY WHICH YOU RETRIEVED IT.

So perhaps recognition and recall could be thought of as bodily processes, the results of which can (sometimes) become conscious.

Although we cannot say definitely what the mind is, we have ideas about what it does. The mind allows us to see the world and act voluntarily on it. Seeing, hearing, touching and all other sensations take place in the mind. So does the experience of emotions.

MOVEMENT (OFTEN CALLED MOTOR ACTION), THINKING, REMEMBERING AND PLANNING SEEM TO ISSUE FROM THE MIND. MIND ALSO INCLUDES THE SENSE OF SELF AND THE SENSE OF FREE WILL.

The Greeks gave us a mentalistic psychology full of words like feel, think, want and decide. This became our common sense or folk psychology. But is it adequate for present day purposes? How well do the metaphors of mind and self map onto our knowledge of how the brain works? These questions lie at the heart of this book.

Meet the Brain

The average human brain weighs around three pounds or 1.4 kilos. Its most obvious features are the left and right hemispheres (LH and RH), which enclose most other (sub-cortical) parts, and the walnut-shaped cerebellum (little brain) at the rear where the spinal cord emerges. The surface of the hemispheres is cortical tissue (from the Latin, cortex, “bark”) which is crumpled or convoluted. The convolutions increase the cortical surface area available within the confines of the skull. In many ancient languages, the word for brain and bone marrow

In many ancient languages, the word for brain and bone marrow was the same. The ancient Greeks and the Chinese thought both of these grew from semen.

Egyptians of The Middle Kingdom (c. 2040–1786 B.C.) were so unimpressed by the brain that they did not preserve it with the rest of the body, as they did the heart, lungs, liver, and kidneys.

WE SCOOPED IT OUT THROUGH THE NOSTRILS AND THREW IT AWAY.

Matter or Spirit?

The Greek physician Hippocrates (c. 460–377 B.C.) rejected the idea that gods and spirits cause physical and mental ill-health. He gave a purely materialist account of body and mind.

Plato (429–347 B.C.) did not accept all of this materialist humoral theory. He believed in a Soul with three parts.

ALL SENSATION, THOUGHT AND CONTROL OF THE BODY ARE IN THE BRAIN.

The balance of the four humours – blood, phlegm, bile and black bile – etermined health, mood and temperament. Procedures such as bleeding, starving or purging were used to treat harmful imbalances.

The first part of the soul was immortal, but the second and third were perishable.

Aristotle (384–322 B.C.) knew that touching the brain does not cause any sensation. He judged that the heart must be where sensations happened.

SINCE BLOODLESS ANIMALS DO NOT HAVE BRAINS, THE FUNCTION OF THE BRAIN MUST BE TO COOL HOT BLOOD RISING FROM THE HEART. THAT’S WRONG!

Galen (129-c. 199 A.D.), a Greek physician in Roman times, relied on animal dissection, experiments, clinical practice and perhaps observations of wounded gladiators. He concluded that the brain is the organ of sensation and voluntary movement.

Debate over the brain hypothesis versus the cardiac hypothesis

Pioneer Map-Makers

The great age of European map-making and navigation began in the Renaissance. Maps were being drawn not only of “new worlds” across the seas, but up there in the skies by astronomers like Nicholas Copernicus (1473–1543) and Galileo Galilei (1564–1642), and also inside the body by pioneer anatomists, Leonardo da Vinci (1452–1519), Andreas Vesalius (1514–64) and others.

IN EVERY DIRECTION, THERE IS NEW KNOWLEDGE.

The Mind of the Gaps

From early Greek times, supporters of the brain hypothesis believed that the soul and mental faculties were located not in the tissue of the brain but in the internal cavities known as the ventricles.

Vesalius taught that inhaled air and vital spirits rising from the heart came together in the ventricles and were transformed into animal spirits. These were distributed through hollow channels to the organs of sensation and motion. This was an early approximation to a chemical theory of how nerves work.

ANIMAL SPIRITS GIVE OFF WASTE PRODUCTS, SUCH AS RISING VAPOURS AND DESCENDING PHLEGM.

Ventricles, Tissues and the Mind

There were arguments over just how many ventricles the brain had. Different functions – such as memory, thought, judgement and reason – were said to be localized in different ventricles. This went on until the arrival of Franciscus de la Boë (known as Sylvius, 1614–72) and Thomas Willis (1621–75).

For the philosopher