on April 12, 2007
With his book "The Accidental Mind", David Linden has given us a wonderful tour of our own brains. He describes this organ and its many interweaving functions 'from the ground up', carefully using terms and analogies that a non-scientist would understand. Dispelling the notion that the brain is either perfect or efficient, David examines this organ as it exists in animals and humans, with the focus on the latter. We begin with basic brain chemistry and mechanisms, and then delve chapter by chapter into such fascinating topics as memory, emotions, personality, sexuality, and dreams. As a professor at Johns Hopkins University, David has access to all the latest research. He covers each subject in just enough detail while leaving out the more technical aspects. This is not another dull textbook, as David laces it with both humor and the occasional personal anecdote. Near the end, David suggests why the human mind would believe in God. He delicately handles this contentious subject by not saying whether God exists (or not). Rather, David proposes reasonably why the mind would be inclined to believe.
David Linden's "The Accidental Mind" is a neat little book. He has two main purposes: (a) to write a readable introduction on brain science, accessible to nonspecialists; (b) to make the case that (page 6) `. . .the brain is an inelegant and inefficient agglomeration of stuff, which nonetheless works surprisingly well." As to the first point, this volume is a far cry from the magnificent work, Michael Gazzaniga's The Cognitive Neurosciences III: Third Edition. However, if one is not well steeped in knowledge and understanding of the neurosciences, Gazzaniga's edited work is close to impenetrable. This book is well and crisply written, explaining simply how neurons work the structure of the brain, how the brain develops, and so on.
As to the second point? He asserts that, quoting Francois Jacob (Page 6), "'Evolution is a tinkerer, not an engineer." That is, evolution operates on organisms as they are and then the process of change takes advantage of the material already existent to adapt to new conditions and challenges. Thus, the human brain is mounted on older, more primitive structures, in an ill fitting complex. As he says (page 21): "The brain is built like an ice cream cone (and you are the top scoop): Through evolutionary time, as higher functions were added, a new scoop was placed on top, but the lower scoops were left largely unchanged."
Thereafter, he speaks of the structure of the brain, how the fully mature human brain develops (with both nature and nurture having roles to play), how the brain is associated with all manner of emotions, learning, religion, and so on.
The Ninth chapter has a title that speaks directly to Linden's first theme--"The Unintelligent Design of the Brain." Here, he slyly critiques advocates of the "Intelligent Design" perspective by noting that the brain is hardly an exemplar of some great design. As noted already, he sees the brain as inefficient and "jury-rigged."
This is a book that provides plenty of insight into how neuroscientists study the structure and function of the brain--and presents some of the exciting possibilities for future research.
In sum, this is a work that ought to be attended to by those interested in the brain sciences, but who cannot readily read the technical literature.
on May 19, 2007
This book is a good introduction to many of the things we know and don't know about how mammalian (especially human) brains work. I see it as a story, starting with some basic bio and neuro chemistry, hitting some brain architecture, and proceeding to touch on learning and memory, sleeping and dreaming, love, and even religion. The climax of the story is the "unintelligent" design of the brain and how it relates to arguments of intelligent design.
This book is fairly easy reading but is aimed at those with at lease some background in science. Prof. Linden is at the top of his game professionally and has a great sense of humor (check out the Absolut Purkinje on his web page at Johns Hopkins!). As you'd expect from a general intro, there isn't too much depth here. When you get hungry for more, The Quest for Consciousness by Christof Koch delivers the next step up in a technical overview of brain function and contains a much more extensive bibliography.
The greatest fear among those who reject Charles Darwin's "Dangerous Idea" is the implications the concept holds for human beings. Our brain, they often claim, demonstrates how far we are from the other animals. It must have been designed by "divine intelligence". Not so, says David Linden. Our brain is something cobbled together over millions of years, parts and functions being added over time to produce that kilogramme of matter in our heads. He likens the building-up process to a multi-scoop ice cream cone. In this finely written overview, he explains the brain's structure and functions, relating them to earlier sources with clarity and wit.
The bottom of the ice-cream cone is the brainstem, an ancient structure controlling much of the body's major systems like heartbeat and breathing. Many of the body's communication with the rest of the brain pass through this part. Above the brainstem is the cerebellum, the first "scoop". The cerebellum acts as a signal filter, inhibiting "expected" sensations like your clothing against your skin. When something detectable as not part of "normal" conditions arises, the cerebellum passes those signals to the rest of the brain. That's when the real action begins. Above the cerebellum lies the midbrain, which is the first recipient of visual and sound signals. In some animals, such as frogs, he notes, this is the primary sensory area. Our midbrain, Linden declares, is symbolic of what he calls "brain kludge". It's an archaic region retained from earlier ancestral creatures for very limited processes. Moving upward and forward we encounter two elements, the thalamus and hypothalamus, the former being a major relay station for signals within and to and from the brain. Near these two is the amygdala, the centre of fear and aggression - the "flight or fight" controller that is an obvious holdover from early times.
If there is a "human" area in our brains, it is the cortex. In dealing with its role, the author takes us through how neuronal cells are structured and operate. They are, he notes, a flawed example of "design". Brains are often compared to computers, but the network of neuronal cells is a patchwork of bad connections, leaking signals and is depressingly slow. Copper wire is several orders of magnitude better at passing information. Describing somebody as being "quick minded" reveals we don't really know what's going on in there. There are, Linden reminds us, 100 billion neurons residing in the brain, with 500 trillion synapses - the contact point for brain signals - connecting them. But the distribution is unequal with contact points ranging from 0 to 200 000. No wonder some thoughts "go astray" and "memory fails"!
Knowledge of the brain rests heavily on those who have suffered injury or lesions in particular areas. Today, these are identified by electronic scanners, but no account of the brain would be complete without the early 19th Century story of Phineas Gage. A steel rod through his skull failed to kill him, but his personality was changed forever. Linden recounts the studies initiated by this accident, and goes on to describe the roots of other behaviour traits. He discusses vision, hearing, sleep and dreaming, and, of course, sex. Studies performed on what happens in the brain during orgasm make almost hilarious reading. Even Linden is left wondering just how the subjects coped. His explanation of why humans seem to bond better than other creatures, even our primate cousins is of particular interest. Although the word "love" appears in the subtitle, there's little mention of it in the text. It's not really related to how the brain works. You are cautioned not to jump to Chapter Six before reading the introductory material.
Linden's chapter on why humans have religion is necessarily thin. Little work has been done on this topic. Even what has been done is rudimentary and sketchy. He compares some representative ideas about gods and spirits, noting that there is some uniformity among them. He dismisses any suggestion of a "god part of the brain" or genes prompting for "faith". Instead, he says, there is a tendency for the brain, seen in other mental functions such as vision, to seek "coherent, gap-free stories". The brain "fills in" when it isn't receiving continuous information. There are many forms of this "filling-in", as some patients have exhibited, which Linden refers to as "confabulation". This isn't a form of "making up" stories, since the individuals truly believe what they are saying. They simply have no way of knowing the tale isn't true. It was a surprise to this reviewer that no mention of sensory deprivation studies dealing with this topic was introduced by the author.
Finally, as all writers of science in the US seem compelled to do, Linden responds the rising challenge of "intelligent design". The simple answer is that the notion is a weak attempt to explain what is either unknown or poorly understood. Why US scientists or science journalists must descend to sparring with this elusive concept is both astonishing and worrying. Many astute thinkers and writers have demolished "ID". Why does it need yet another post-mortem? Linden does as good a job as any at demonstrating the falsity of proponents like Behe, Dembski and Johnson. In doing so, he concludes with an appeal for more work to build on what is known about the brain and its evolutionary foundation. [stephen a. haines - Ottawa, Canada]
on January 30, 2008
The subtitle was the hook: "How Brain Evolution Has Given Us Love, Memory, Dreams and God." I expected a real intellectual ride on a par with "The Origins of Consciousness" or "The Social Construction of Reality," with Linden making provocative assertions with the neurology pointing the way, or better, announcing some spectacular recent finds. Though the author does cover those bases, he is much too good a scientist (read: cautious, incremental) to justify the editor's or publicist's perfunctory tagline.
No, this isn't a mind-bender for the general reader, but more like a sound, responsible textbook (or college lecture, with rock music and pop culture analogies to liven the talk) on the state of the science. What isn't mentioned in the subtitle is his best point: that evolution has given us an inefficient agglomeration of add-ons and annexes (a "kludge") rather than a streamlined brain design.
Love? Derived from the opportunism that favored lifelong reproductive human pairings. Memory? Some good points are communicated, though hardly revelatory. Dreams? Interesting and subtle functionality, though we need to know more. God? The end product of dreams and our constant creation of narratives to explain the world. The sociologists have more compelling--and focused--recent theories here.
I'm glad I read Linden's book, but I'm not sure I would have bought it without that witty pumpkin on the cover or clever subtitle. "Consciousness: A User's Guide" or "Consciousness Explained" might have been more what I was looking for.
on April 26, 2007
With this fun and clearly written book the author addresses a common misconception about the brain: that its design is optimal. The brain is amazing, it makes us amazing, but Linden walks us through science showing that its design is better described as haphazard. Using a computer program as a metaphor, the brain's design is not indicative of great forethought and upfront planning. Instead, it looks more like a simple program that was then adapted to be more complex again and again. The result, like simple computer programs that are slowly adapted to be more complex, is that some of the organization is unfortunate, non-optimal, and at times even a little bizarre. David Linden develops this argument with great wit, clarity and sound logic. Read this book to broaden your view of yourself and the world.
on May 7, 2007
I picked up the book in the bookstore to browse through it, and just could not put it down. Linden is a first-class educator. His book describes the physical and computational architecture and development of the brain/mind with clear and memorable analogies. Personally, I enjoyed the chapter on sleep and dreaming the best, but Linden covers a lot of ground. His main point is that the brain isn't a highly-optimized computer, but instead is a layered design that keeps a lot of out-moded machinery around in the lower layers. I have read several other books on this topic (Ratey, Ramachandra, Sacks, Carter), and Linden's book seems to strike the best balance between information and entertainment. P.S. Since I'm a computer scientist, this book also gives me some hope that one day we'll mimic the brain. Since the brain is so inefficiently made, that means we can design an artificial one without all the overhead.
"The Accidental Mind" is basically a neural guide to the brain showing how the brain is basically a kluge of lots of things evolving over millions of years. Not that I have to be convinced about evolution, but the book does present some interesting thoughts along the way, like:
1. Human experience (feelings, perceptions, actions, etc) has taken the inefficient design of the brain and evolved its structure into the remarkable thing it is, our very humaness.
2. The brain is like an 'ice cream scoop', with the highest functions being added to the top, scoop by scoop, so to speak, during the course of evolution. Highest functions at the top, lowest at the bottom.
3. Human constructs of neurons, gliel cells, axons, dendrites, synapses, etc. are not much different from a worm, hence evolution is a logical conclusion.
4. Nature vs nurture - result is in the middle - for instance, about 50% of intelligence is because of genes, the rest is not genetic.
5. There are critical periods for certain aspects of learning - after 6-12 months a baby exposed to two languages can no longer have perfect accents in both languages. Also, there is an argument that whole language vs just phonetic learning of language is better during the critical early time period.
6. Sensations and emotions don't result in totally accurate pictures, so the brain fills in gaps (saccades). e.g. eyes jumping around.
7. Higher brain functions involve both memory and emotion, emotion basically 'underlining' something for easier recall. A memory is really a distributed network of associated memories, and are the building blocks of logic, reasoning, decision-making and social cognition. That is why if some memory is forgotten (misattribution - error), it can sometimes be pieced together from scattered locations. The reason young child-abuse victims are more open to suggestibility during interviews is because the brain/memory network is still growing.
8. Human sexual behavior is mainly influenced by culture, less by genes. That is why human females have concealed ovulation and humans engage in recreation sex - perhaps in order to build long-term bonding, longer times needed to raise children and for the male to more likely be around long enough.
9. Gender identity is a complex interplay of biological and social factors. Male homosexuality likely linked to the X chromosome. Also, a mom's stress could affect the male fetus.
10. Women are better at arithmetic, while men are better at mathematical reasoning, in general. Different cognitive styles - not necessarily genetic, but likely.
11. Oxytocin surges during childbirth and breastfeeding - likely in order to enhance bonding.
12. Sleep deprivation can make the brain delusional, suggestible, and/or psychotic - hence can be considered torture if intentionally caused. REM sleep, dreams are important for memory consolidation.
13. Religion is cross-cultural, even its variety is constrained. Why? The brain looks to develop narratives to fill in gaps, like visual 'saccades'. Narrative functioning of the brain can't be shut off. Confabulation - piecing together old memories for a narrative context. Therefore, we are predisposed to believing things we can't prove.
14. Intelligent Design is not even a scientific theory since it is not falsifiable.
So, the book does give a pretty good overview of human brain function - many technical details of the brain, plus explanations and scientific thoughts about what makes us 'human'.
on April 25, 2007
It's rare that a brainy scientist studying something as complex as the brain can explain his field of study in a way non-scientists can even begin to understand. It's even more rare that a scientist can write a page-turner about his field of study that makes his science accessible to the average reader. But that is just what Linden has accomplished. Reading this book not only provided enough cocktail party quips to last a lifetime (did you know that the brain is built like an ice-cream cone?), it also caused me to consider dreams, memory, religion, sight and my narrative perception of the world in different and mind-blowing ways. A great book to have and to share.
on May 30, 2007
I found The Accidental Mind a well written, humorous and thought-provoking introduction to neuroscience and to some profound ideas about evolution and other topics. It's the kind of book that makes you interrupt your partner's reading every five minutes with "Hey, listen to this...." If Dr. Linden lectures as entertainingly and interestingly as he writes, his classes at Johns Hopkins University must be in great demand.