Deric Bownds


BIOLOGY OF MIND
PREFACE

Until recently the study of mind, consciousness, and feelings has been a subject for philosophy and religion, outside the province of hard science. This has changed in just the past few years, as advances in anthropology, animal behavior, evolutionary theory, linguistics, molecular neurobiology, psychology, and cognitive neuroscience have brought us to the threshold of resolving questions that have occupied philosophers for millennia:

" How does the human brain generate a "self"?

" What is the nature of the narrative "I" that we experience in our heads?

" What is the relationship between reason and emotion?

" How do genetic and environmental factors interact to determine the structure of our brains?

Interdisciplinary approaches to these questions are making it possible to construct models of mind and emotion that are amenable to experimental tests. The message of this book is that each of us is a society of minds that emerge from our evolutionary history and from the way our brains form as we grow up in a particular natural ecology and cultural setting. Each chapter contributes a few perspectives on the society of mind that forms, describing a subset of its elements. From our evolutionary history we derive the genetic instructions with which we begin life, and the particular mind and brain that each of us then grows are shaped and patterned by our surroundings. There are many roads to understanding our minds, many different windows through which we must peer. We approach the target from different directions when we take up the perspectives provided by neurobiology, cognitive psychology, animal behavior, linguistics, and evolutionary biology. We need to consider successive glimpses of different aspects of "mind." There are many ways to model ourselves, multiple versions of "this is I." We can utilize information on how our nervous systems evolved over millions of years, as well as high-technology gadgets designed to peer inside our brains as they work. This book tries to mix these two approaches---to assemble a description of our minds as a vast collective of agents that interact to construct an unconscious background out of which a narrative "I" emerges. You may well discover that the new ideas we suggest change your everyday perceptions and actions.

This writing began for the purpose of supporting a course for both science and non-science majors at the University of Wisconsin in Madison. It has proved useful in offering a continuous background, overview, and storyline that supports presentation of current work in each of the areas covered. Each chapter provides the core material for 1 to 3 of the approximately 45 lectures in a standard semester. This present book is an effort to share with a wider audience some of the fascination and excitement that have permeated both public and university lectures on the subjects it addresses. It falls somewhere in between a traditional academic text and a popular account. You will have an easier time with the book if you have had an introductory high school or college biology course. Sidebars are used at intervals to emphasize main points or self-exercises. At the end of each chapter is a summary, followed by thought questions and suggestions for further reading. Key words are italicized and defined in a glossary at the end of the book. If you would like more information on a particular subject that interests you, the references provided for each chapter should enable you to pursue the matter further. Detailed citations that support many of the factual statements made in the text can be found in a draft of this book on the World Wide Web at http://mind.bocklabs.wisc.edu.

In parts of this book, topics have been grouped in a way that corresponds to our subjective living experience, things we do every day---hence the chapters on perceiving mind, acting mind, emotional mind, and linguistic mind. The ideas can become more real and interesting if we use our subjective experience to engage them, and occasionally simple exercises are suggested to illustrate some of the mechanisms we consider. Such exercises can be instructive and fun if we don't lose sight of two points. First, what we think and feel is just the tip of the iceberg, compared with what is really going on in our brains. What we are aware of is something like the display on a computer screen as distinguished from the inner working of the computer. Second, our subjective experience can be very biased and distorted by factors of which we are unaware. Numerous psychological experiments have documented that our perceptions are not necessarily naive, reporting actual events outside or inside our bodies. Rather, they can be influenced by what we or someone else expects us to perceive. This is why traditional scientific inquiry insists on eventually putting our subjective insights into a form that can be tested impersonally by independent observers. Each of us can imagine that a particular process is going on inside our head, but it will remain thoroughly hidden there until its presence can be inferred from a third-person experimental demonstration.

This book encourages you to weave, through its ideas about how our minds work, a fabric of your own personal experience, feeling the richness deepen as these ideas inform your introspection about the mechanisms of your thinking, feeling, and acting. Our brains can rearrange space, time, thoughts, and emotions. Some of these processes can be made accessible to our awareness through simple mental exercises. It is not too difficult to sense motor programs of which we are usually unaware, to separate thoughts from emotions, and to note some of the ways in which we generate selves. Being aware of the mind's activities in the fractions of a second after new situations arise can have the practical consequence of offering some new options for our behavior. Questioning our common-sense perceptions of reality can also create a feeling of strangeness. Brain mechanisms are not guaranteed to feel familiar, warm, and cuddly. The objective reality we assume to be outside ourselves depends on our particular processes of perceiving it.

We begin with some background information in Chapter 1, Thinking About Thinking, which defines some terms and considers how a biological explanation of mind and consciousness might be approached. It is a necessary background for the four main parts of the book. Part I, Evolving Mind, is a description of our evolutionary history, starting with the Big Bang that created the universe and culminated in minds that can write and read a page like this one. Chapter 2, Origins of Mind, is an overview of the path from the appearance of the first simple behaviors of bacteria to the complex routines of our own brains, discussing the possible origins of such phenomena as sensations, perceptions, and emotions. It also offers a simple description of some of the basic processes that underlie organic evolution. Chapter 3, Structures of Mind, describes how our modern human minds encapsulate a series of more primitive minds and brains that arose during vertebrate evolution. It provides an introduction to brain structures and some modern techniques used to study the brain. Chapter 4, Primate Mind, begins with a brief general discussion of the minds of animals and then focuses on the primate line from which we are derived, examining similarities and differences between our minds and those of monkeys and apes. Chapter 5, Hominid Mind, discusses stages in the evolution of intelligence in early hominids, the origins of language, and the emergence of modern humans. We consider some of the arguments that there is a universal evolved human psychology: that in many of our reproductive and social behaviors, we appear to express unconscious psychological mechanisms that evolved to meet conditions of a vanished time hundreds of thousands of years ago, long before the invention of agriculture and cities, when humans existed as bands of hunter-gatherers.

Part II, Developing Mind, describes how the templates set by our evolutionary history engage an ongoing interaction with the actual physical and cultural environment we face to generate the structures and modules of our modern minds and selves. Chapter 6, Plastic Mind, gives a brief outline of the development of our brains and discusses the plasticity in this process that evolved to permit us to adapt to novel or unpredictable environments. This plasticity is maintained to some extent in our adult brains, and it underlies both the learning of new skills and facts and the ability to recover from brain injuries. Our brains can actually rewire themselves when we learn new manual skills or learn to discriminate some sensory input in a more detailed way. Far from being locked in, as was thought until only a few years ago, many nerve connections in our brains are constantly shuffling about, testing what works best. Chapter 7, Minds and Selves, discusses the development and construction of our human selves. This process requires elaborate feats of learning and memory and draws on mechanisms that are a continuation of those that were active during the early development of the brain. We look at stages in human development and then consider interesting clues to the nature of a self that are obtained from studies on genetics, abnormal development, and patients with brain lesions. Nothing escapes the nudging of our genes. They set the limits on our repertoires of development and behavior. This is not to say we are their prisoners, but rather that we should appreciate how our options have been shaped by them.

Part III of the book, ""Society of Mind, takes a plunge into thinking about the many mind, brain, and body modules that underlie our perceptions and actions in the world---modules that form as a consequence of our evolutionary and individual developmental histories. Chapter 8, Perceiving Mind, offers a brief description of how our brains automatically filter and select, through processes of which we are largely unconscious, what fraction of the mass of incoming sensory information impinging on us is relevant for awareness. We frequently see in the external world what our previous experience leads us to expect to see, not what is really there. This is contrary to our common-sense notion that we see a world out there as it is, objectively. After a brief review of some characteristics of our sensing and perceiving, we shift our focus to visual competence. Studies on the visual brains of cats, monkeys, and humans have yielded fascinating insights into what visual consciousness is and where it resides. Chapter 9, Acting Mind, emphasizes the perspective that the most fundamental role of a biological mind is to move a biological body, and to do so quickly if danger is nearby. Mind and brain need to be defined in a way that considers the whole body and its ongoing reciprocal interactions with its world. This chapter offers a brief description of some of the brain structures involved in movement control and also considers models for movement control.

In Chapter 10 of Part III, Emotional Mind, we continue a discussion, begun in Chapter 2, of emotions as evolutionary adaptations, and then we review modern experiments that suggest that our emotional minds are the foundation of our rational minds. The cathedrals of our intellect are infused by the inborn emotional wiring of our reptilian brainstem. It is much better to be informed of the ways in which our reason can be distorted as well as enhanced by our emotions than to imagine that we can always face the problems of the world in an objective way. Brain pathways that process emotional responses are more rapid than those that underlie reasoned ones, and some simple exercises will permit you to experience this distinction for yourself. The chapter ends with a topic of contemporary significance for most of us: how emotions that evolved as adaptations to our ancestral conditions can easily be misapplied to our modern circumstances, leading to debilitating stress and disease. Chapter 11, Linguistic Mind, continues discussions begun in Chapter 5, on the evolutionary origins of language, and in Chapter 7, on the development of language, to review evidence that underlying brain mechanisms support the language competence that we have evolved. This leads to the formation of localized modules in the brain that specialize in different aspects of language comprehension and generation. The location of some of these modules is revealed by brain lesions and also by imaging the activity of the brain during language performance.

Part IV of the book, Modern Mind, draws together a number of threads that run through the book to summarize our current understanding of the selves generated by our brains---selves generated just as automatically as a bird builds a nest or a beaver builds a dam. Chapter 12,Conscious Mind, looks from several different angles at the consciousness we construct. Ingenious experiments of cognitive psychology reveal agents of our minds that reorder time and space, and suggest that our perceptions and actions can be modeled as the result of an ongoing competition between alternative outcomes. This chapter makes the point that there is no central place in the brain where "it all comes together" and mentions some classical debates on whether the problem of consciousness can be solved. There isn't any "I" inside our heads, at least in the way we commonly suppose. Societies of neuronal agents carry out chores in a way that is more analogous to the performance of a chamber music group than to an orchestra with a central conductor. Further insight into the nature of our consciousness comes from studies on its altered states, as during sleep. We are left with the clear message that our conscious awareness is a very, very small fraction of what is going on in our brains---that most of the activity in our heads is being carried out by another "creature" largely inaccessible to our introspection, as alien to us as occupation by an extraterrestrial interloper.

Chapter 13, Theoretic Mind, brings the evolutionary story to the present by first considering the emergence of the human mind that is the basis of the explosion of human activity and culture in the past 4000 years. This is the mind that has generated external forms of symbol storage, such paraphernalia of our modern lives as the books and electronic media that account for much of what is in our heads. We all have modern minds coexisting with emotional and psychological machinery that evolved to meet the conditions of the Paleolithic era, and such machinery frequently is poorly suited to the conditions of modern industrial societies. The modern rational and individualistic self that many of us take for granted is a relatively recent phenomenon. Over most of human history, a more collective identity prevailed. But now, more than ever before, we are not just an unconscious part of organic evolution, but consciously and actively direct it. Does our knowledge of the mind and the past give us a crystal ball for predicting the future evolution of mind? The answer is no, but what we have learned does suggest some appropriate mental tools and attitudes for approaching an understanding of the evolution of evolution, or how change changes itself.

There is, in our efforts to understand how our human minds work, an urgency that derives from more than just our natural curiosity, for on its present course the human mind may be driving itself to extinction. In the last 50 years, the human population has increased more rapidly, and we have learned more about biology, than in all of previous human history. The rate of extinction inflicted on animal and plant species by humans is so great that our grandchildren may know only half the plant and animal species we see today. It is as though we all shared a secret, unspoken plan to go on consuming the world until there is no more left. If more people took to heart the material we will be considering---which illustrates the relativity of our mental processes and cultural styles, how intimately we are bound to our environment, and how many of our behaviors are adaptations to a long vanished past---perhaps we might be less intrusive on each other and on the environment. If we hope to shape our future in an intelligent way, we must understand both the evolutionary past that shaped our current behavioral repertoire and the details of how that repertoire is played out in the present.


Acknowledgments

I would like to acknowledge the early encouragement given to this book project by Owen Flanagan, Daniel Dennett, and Stephen Kosslyn. Marlin, Helen, Jonathan, and Sarah Bownds, and my partner Len Walker, have provided crucial family support. Several reviewers have provided invaluable comments, and I am indebted in particular to my colleague A.O.W Stretton for his close and critical reading of the manuscript. Several students, Cosma Shalizi, Deana Sasaki and Jean Hetzel, have provided crucial assistance with editing, and glossary and manuscript preparation. Finally, I have thoroughly enjoyed interactions with publisher Patrick Fitzgerald, developmental editor Amy Marks, and production editor Susan Graham..

 

 
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