Better Than One

How We Each Have Two Minds

David J. Uings

• Publisher: Routledge
• Year: 2018
• Topic: Psychology
• eBook ISBN:
  9780429911361
• Subtopic: History & Theory in Psychology
• Index: Psychology

Starting with research by Nobel laureate Roger Sperry into split-brain patients, this book sets out the evidence that there is a conscious mind in each hemisphere of the human brain. Two forms of consciousness are distinguished, and the difference in the consciousness of each mind revealed. The two different pathways within the human visual system and their effect on human behaviour are described, as well as differences in the memories formed by each mind. Evidence for two minds in the intact human brain is analysed, including psychological experiments and every-day experiences such as sleep-walking and driving on "automatic pilot". Reasons are suggested to explain why the evidence from split-brain patients has been largely ignored, and the views of six authors who have addressed the issue are considered. The presence of two minds - each with its own memories, thoughts, desires, and decisions that are inaccessible to the other - has important implications for all those whose work involves the mind, including psychologists, psycho-therapists and lawyers.

Part I
The Background

As a postgraduate research student of philosophy, I set out to investigate the phenomenon called self-deception. I saw no point in limiting my reading to what philosophers had to say on the subject, but wanted to find in addition empirical evidence about the mind and brain. I came across a web site where it was claimed that during the course of human evolution a second mind had developed in the left hemisphere alongside the development of language.

Pursuing this line of enquiry led me to the research of Roger Sperry and his colleagues into patients whose brains had been split in two by cutting the link between the hemispheres. I was amazed to find that this research had been almost totally ignored by philosophers concerned with the mind, and by academic psychologists.

The evidence that there are two minds at work in split-brain patients led me to search for evidence that there are two minds in all of us. This book sets out the evidence for two minds and considers some of the implications.

Part I provides the background information that is needed in order to assess the evidence. After setting out the basis of my claim in Chapter One, I provide a brief introduction to the structure of the human brain. I then consider three key concepts—mind, consciousness, and language—before ending this part by looking at the human visual system and memory.

NOTE: Throughout this volume, the terms “he”, “him” and “his” will be used of unidentified individuals without any implications of gender, to avoid the cumbersome use of “he or she” and so on.

Chapter One
The case outlined

Throughout history, we have been reluctant to accept new ideas when they conflict with our well-established picture of the world and of ourselves. It took time to accept that the world is round; to recognise that the earth is not the centre of the universe; to acknowledge that the earth is far older than the six millennia suggested by the Bible, and that humans have evolved through natural selection. This book is about another new idea that has been generally ignored or rejected, especially by those with a particular interest in the issue: philosophers and psychologists. I refer to the growing evidence that we human beings have not one, but two, minds.

The blurb on the back cover of the book In Two Minds: Dual Processes and Beyond (Evans & Frankish, 2009a), claims that it “explores the idea that we have two minds”. Within the book, however, very little is said to justify this claim. In the opening chapter, for example, there are numerous references to “dual systems” and “dual processes”, but only two occurrences of “two minds”.

Indeed, the idea that we have two minds is dismissed as “probably wrong” by Evans, one of the book’s editors. This is what he says:

I define “mind” as a high-level cognitive system capable of representing the external world and acting upon it in order to serve the goals of the organism. The two minds hypothesis is that the human brain contains not one but two parallel systems for doing this. Animals, according to this view, have but one system corresponding to the “old mind” in human beings. Humans have a second “new” mind, which coexists in uneasy coalition with the first, sometimes coming into direct conflict with it. This is a strong, even start-ling hypothesis, which makes it very interesting (if probably wrong!).¹ (Evans, 2009, p. 35)

The contributors to the book comprise psychologists and philosophers, with the two editors coming from either camp. The central claim is of two systems, but the contributors cannot agree on whether we have two systems or two processes, or more than two systems or processes, or on what basis to distinguish between different systems or different processes. These disagreements are symptomatic of the whole field of mind studies.

Confusion among philosophers

The philosopher Jonathan Lowe begins his An Introduction to the Philosophy of Mind by explaining that minds do not exist (2000, pp. 1–2). There is mind, he claims—on a par with terms such as music or commerce—but not individual things called mind. Contrast this approach with that of another philosopher, Peter Carruthers, whose book The Architecture of the Mind treats the mind as an entity comprised of many modules (2006, pp. 1 ff.).

There is a similar breadth of disagreement on the related subject of consciousness. One philosopher, John Searle, claims that consciousness is a natural biological phenomenon, on a par with digestion (1992, p. 1). By contrast, Colin McGinn (1989) has argued that we will never be able to explain consciousness because our brains are not equipped to do so.

Given the extent of disagreement that exists among psychologists and philosophers of mind, you might expect that they would seize on any information available from neuroscientific research that would throw light on the problem. Two neuroscientists, Roger Sperry and Gerald Edelman, have made specific claims about the existence of two minds/ two forms of consciousness in humans. But you will find no mention of either claim within any of the contributions to In Two Minds.

It is also noteworthy that little mention of such research can be found in the philosophical literature. Of the three books mentioned two paragraphs earlier, neither Lowe nor Carruthers make any mention of either Edelman or Sperry, and Searle only mentions Edelman in order to attribute to him the term “remembered present”. In a major anthology on consciousness (Block, Flanagan, & Güzeldere (1997)), in which forty authors contribute fifty articles on the subject, only one article makes reference to Sperry’s research results.

Although philosophers and psychologists have largely ignored Sperry, three recent publications—by a neuro-anatomist (Bolte Taylor, 2008), a psychiatrist (McGilchrist, 2009), and a student of English literature (Tweedy, 2012)—have made reference to his work and to differences between the two hemispheres of the human brain. I will discuss their views and how they relate to the claim of two minds in Part III. Before then, my aim is to show that each of us does, in truth, have two minds, using the insights from Sperry and Edelman as a starting point. I will summarise Sperry’s conclusions at this point, but defer a review of the supporting evidence to Part II.

Sperry's research

Roger Sperry obtained a master’s in psychology and a doctorate in zoology, before joining the California Institute of Technology in the 1950s as professor of psychobiology. In that post he led a team researching “split-brain” patients. These were individuals who had undergone an operation in the 1960s² to treat severe epilepsy. Using a procedure called callosotomy, surgeons in California had severed the corpus callosum, the bundle of nerve cells forming the link between the two halves of the brain (see Figure 3, p. 15).

Many essential brain processes are carried out in only one or the other hemisphere (see Chapter Two), so you would expect the severing of the link between them to have a major impact on the lives of those undergoing it. Sperry’s investigations into the effects of the operation led to a remarkable finding: after a recovery period of six months to a year, the patients were able to lead a normal life. In his speech accepting the Nobel Prize in Physiology or Medicine, Sperry reported that these patients could go through “a casual first meeting or conversation or even through an entire routine medical exam” without their condition being detected (1981, p. 2).

His second finding was even more remarkable: split-brain patients had two minds! Because of the way that functions such as sight and hand control are divided between the two hemispheres of the human brain (see Chapter Two), Sperry and his colleagues were able to examine the operation of each half of the brain independently.

Until then, the classic view was that in humans the left hemisphere was dominant, and the right hemisphere performed a minor, subsidiary role. But Sperry concluded that the right hemisphere is “a conscious system in its own right, perceiving, thinking, remembering, reasoning, willing and emoting, all at a characteristically human level, and … both the left and the right hemispheres may be conscious simultaneously in different, even in mutually conflicting, mental experiences that run along in parallel” (cited in Horowitz, 1981, p. 3).

I will discuss the meaning of the terms “mind” and “consciousness” in more detail in Chapters Three and Four, but if split-brain patients have indeed two conscious systems—a mind in each hemisphere—a question immediately arises.

Question 1. If split-brain patients provide evidence of a mind in each hemisphere after their operation, did these separate minds exist before the operation? Or, put another way, do we all have two minds?

As a first step to answering that question, I turn to the work of another winner of the Nobel Prize in Physiology or Medicine, Gerald Edelman. After training as a medical doctor, Edelman entered medical research, and won his Nobel Prize for his work on the structure of antibodies. He then turned his attention to the structure of the brain, and developed the Theory of Neuronal Group Selection (1987) as the biological basis of consciousness.

My concern is not with the detail of his theory, but with a central claim that he makes about consciousness. He draws a distinction (2004, pp. 8–9) between primary consciousness, which humans share with the higher animals, and higher-order consciousness, only found—at least in a complete sense—in humans, and associated with the development of language. He claims that animals with primary consciousness are conscious of their environment: they can think about what they sense, and act accordingly. But, he asserts, they have no awareness of being conscious.

By contrast, he says, humans “know what it is like to be conscious … and are conscious of being conscious” (Edelman, 2006, p. 14). But he concludes that “at all times when higher-order consciousness is present, we also possess primary consciousness” (ibid., p. 15). Although Edelman makes reference to Sperry’s conclusions that each hemisphere is independently conscious (ibid., pp. 111–112), he does not propose a specific location for either primary or higher-order consciousness. So we come to a second question.

Question 2. Can the evidence provided by split-brain patients be used to identify different forms of consciousness in each half of the brain?

The answer to this question is a clear “Yes”, but the evidence in support of that conclusion must await a detailed look at the evidence from split-brain patients in Part II. However, I can now set out the claim that I am making.

Each of us has two minds: one mind in the right hemisphere, which I will refer to as the R-mind, and one in the left hemisphere (the L-mind). The R-mind is inherited from our animal ancestors, shares many of its characteristics with animals, and exhibits primary consciousness. The L-mind evolved in humans in association with the development of language, and exhibits higher-order consciousness.

Question 3. How does this claim fit with the claim that there are two systems within the human brain?

The table below lists some of the most commonly accepted properties of these two systems.³

Table 1. Two systems within the human brain.

System 1	System 2
Evolutionarily old	Evolutionarily recent
Shared with animals	Distinctively human
Unconscious	Conscious
Automatic	Controlled
Unassociated with language	Associated with language
Fast	Slow
Not linked to IQ	Linked to IQ

There are some obvious parallels between the pairs of attributes used to distinguish the two systems, and the attributes I claim for the two minds. System 1 is described as evolutionarily old, shared with animals, and unassociated with language. This is consistent with my description of the R-mind. By contrast, System 2 is described as evolution-arily recent, uniquely human, and associated with language, which is consistent with my description of the L-mind. Despite these surface parallels, I will show that it is the presence of two minds that is ...

Table of contents

• Cover
• Half Title
• Title
• Copyright
• Contents
• LIST OF FIGURES
• LIST OF TABLES
• ACKNOWLEDGMENTS
• ABOUT THE AUTHOR
• PART I: THE BACKGROUND
• PART II: THE EVIDENCE
• PART III: REFLECTIONS
• NOTES
• REFERENCES
• INDEX