As preeminent science populizer Richard Dawkins has previously cogently explained, natural selection has ingrained in us a tendency to understand the events around us as the product of a conspiracy theory rather than random accident. You and your future offspring are more likely to survive if you always assume that the rustle in the grass next to you is a tiger, even if 99 times out of 100 it is just the wind. Linden takes this one step further and explains how the brain must impose its own explanations on events, because we are physiologically limited in how much information our senses can take in at one time, and so our left brains must fill in the gaps. Basically our entire experience is based on our brain fooling us into thinking that we are seeing and experiencing the real world in a smooth succession of events, when what we are actually seeing are snippets with our brains filling in the rest. Our tendency to believe that there is some supernatural explanation imposing causality on what would otherwise seem like random events (along with our tendency to believe any governmental conspiracy that is suggested) are products of our brain biology. Our job in life as 21st century rational human beings is to recognize where our brain is biasing us away from the unglamorous truth that in general there is no causality, and to compensate for those tendencies. One only wishes that more scientists would stand up to the second and eighth century fundamentalists who are prisoners of their biology and are seeking to impose their antediluvian views on the rest of us through force. Unfortunately, scientists are timid.

"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'.

I have read books. Books that explain how our brain works. Most of the digestible books tend to explain the brain and the associated human behaviors from evolutionary perspective. In general, they are outwardly focused. However, this book is different. It is taking an inwardly outward approach to understanding our brain. Starts with current inefficient, unfathomable brain whose design seems highly inelegant and ad hoc. For instance, our brain which is only 2% of the body consumes 20% of the energy. On similar lines, the author supports observations with facts. For instance that automatic functions are at the bottom and the higher level functions at the top which supports the incremental design philosophy. Right at the beginning, the author plants the key modules of the brain in very simple manner. Explains the approach scientists take to understand brain. Once the platform is set, the author deep dives into more internal details. Gets into the neurons, axons. Explains the nitti-gritties around it without boring, scaring the reader. Touches up on the effects of well known psychotropic chemicals and poisons and how they interplay at these levels. After which the author zooms out in the realm of sleep, dreams, memory, love and more.

What I liked about this books is the simplicity. No tongue twisting words. Nicely organized right from the beginning to end. Additional thing I liked about this book is that the author has attempted to address all the interesting aspects of brain like learning, memory, human individuality, dreams and inherent religious impulses. I liked how the book progresses from a inelegant design and ends on a philosophical level. The topics are nicely tied together like a beautiful necklace.

All in all the author has stayed true to the philosophy of "Imagine that your audience has zero knowledge but infinite intelligence." Definitely, a must read for all human beings!

-Sachin

Ever wonder why we have dreams; a longer childhood than any other species; recreational sex and long-term pair bonding; other things? Read David Linden's "The Accidental Mind." It's a fascinating exploration of the human brain from one of the leading neuro-scientists in the country.

Our brains are actually not paragons of good engineering, according to Linden. They're more like Rube Goldberg contraptions. For example, the parts of the brain that control lower-level functions are essentially no different from those of rats or frogs. Our brains just have more stuff piled on top. Linden compares the brain to an ice-cream cone, and the bigger parts of our brains that distinguish us from other animals are just more "scoops" piled on top of the lower scoops through our evolutionary history. In addition, primitive functions persist in parts of our brain, giving rise to interesting phenomena such as blindsight. Further, one problem with our brains is that we have evolved functions that are useful in some situations but can be counter-productive in others. For example, the escalation of shoving matches in schoolyards and bars is not all about social dynamics. Indeed, a large part of it is neurological. When you initiate a movement, you tend not to pay attention to the sensations from that movement; you generally don't notice your clothes rubbing up against you when you walk. The cerebellum sends inhibition signals so that the body doesn't feel sensations from self-initiated movements as much. The reason why is that due to our evolutionary history, it's more advantageous to notice a touch from an outside source than from yourself. I'll let Linden describe it- "The cerebellum uses these signals to predict the sensations that are likely to result from this motion. Then the cerebellum sends inhibitory signals to other brain regions to subtract the `expected' sensations from the `total' sensations and thereby change the way they feel to you." (p. 10) In other words, when shoving back, you will try to match the perceived force, but you will always overcompensate by shoving harder than the inhibitory signals. This can become counter-productive. Incidentally, the cerebellum inhibitory signals is also why you can't tickle yourself.

Interestingly, we don't have sex, dreams, long childhoods, and all the rest in spite of our klugish brain design, but because of it. Brain activity is controlled by the firing of neurons and dendrils and synapses. I'll let you read the book to get all the juicy details, but the bottom line is that neuronal activity is actually very inefficient. So to get a brain that can function like ours can, we need lots of neurons firing at once, and that can only happen with a large brain and a large skull. But the number of neurons and synapses is so large it cannot all be specified in the genome- it must come through experience. So our species has neuronal plasticity that can be molded through experience. Hence, our long childhoods. With most other mammals, the male will leave right after mating to find another female. With humans, however, it is advantageous for a female to find a long-term mate, since children cannot fend for themselves for a considerably longer time than other mammals. To have this long-term pair bonding, concealed ovulation developed. "Males tend to buy into this arrangement for two reasons. One is that if the male plays along he can be confident of paternity: he won't be wasting his resources supporting the offspring of another male. Another is that he, and the female, will enjoy the bonding that comes from frequent sex. This bonding and reward is enough to keep humans having sex even when conception is impossible (during pregnancy or even after menopause)." (pp. 149-150)

One important part of building experience is memory. You go through the world with the help of memories of previous experiences. But we need a way to organize and cross-reference this memory for it to be useful. That's where sleep comes in. According to Linden, the best research in the field indicates that the cycles of REM and non-REM sleep help memory to be organized and cross-references, a function that is best done without competing sensory bombardment. Dreams are a result of the bizarre combination of brain functions during sleep- the emotional parts of the brain (amygdala, anterior cortex) are heightened, while the part of the brain that is responsible for logic and decisions (dorsolateral prefrontal cortex) is "turned off." And all of this while the left-brain narrative structure is still on. Linden speculates that religion may have partly originated with some form of dream recollection.

There's lots more that Linden discusses that I could mention- the nature/nurture debate, gender-based brain differences, homosexuality, and the future of brain research. Suffice it to say that this will be a fascinating book for anyone to read. I believe that understanding why we are the way we are will give us a firmer ground for addressing the problems in our world. A reader who wants to understand that could hardly do better than to read this.

The prologue begins, "The Best Thing about being a brain researcher is that, in a very small number of situations, you can appear to have the power of mind reading. Take cocktail parties. Chardonnay in hand, your host makes one of those introductions where he feels compelled to state your occupation.... [Then I say] `You're about to ask if it's true that we only use 10 percent of our brain, aren't you?'"

So, the author is A-list on the cocktail party circuit, and perhaps that accounts for his ability to weave a fascinating tale that is this book. Oh, yes, he is a distinguished scientist as well, so there are some dashes of new science that are fun to know. It is science with an Attitude.

Here's what the author says he tries to do, which is dead-on for a review of this book: "I will be your guide to this strange and often illogical world of neural function ... pointing out the most unusual and counterintuitive aspects of brain and neural design.... I will try to convince you that the constraints of quirky, evolved brain design have ultimately led to many transcendent and unique human characteristics: our long childhoods, our extensive memory capacity (... the substrate upon which our individuality is created by experience), our search for long-term love relationships, our need to create compelling narrative and, ultimately, the universal cultural impulse to create religious explanations.

"Along the way, I will briefly review the biology background you will need to understand the things I am guessing you most want to know about the brain and behavior. You know, the good stuff: emotion, illusion, memory, dreams, love and sex, and, of course, freaky twin stories." [The author knows well what is the "good stuff."]

There is much more. A stunning plus for the book is the illustrations, all of them original, excellent to behold, and some of them an entrancing story in their own right. Evidently, someone found a talented creator, as the illustrations just have to be examples of Intelligent Design.

Did you know that non-REM sleep appears to have evolved as early as the fly, about 500 million years ago? REM sleep is found only in warm-blooded species, including the most primitive surviving mammals, such as the platypus. Appears to be absent in reptiles and amphibians. Why do mammals need REM sleep and reptiles do not? The book has some interesting speculation and interesting experiments showing plausible reasons that are not true.

Did you know dolphins are among those needing the least REM sleep (at under 12 minutes)? Book says they sleep 10 hours total. Makes me wonder if they swim in their sleep to surface to breathe. Horses only sleep 3 hours total. Ferrets do 6 hours of REM and the platypus does a fabulous 8 hours of REM. Wonder what dreams play thru its brain?

The book has a web site for more info, AccidentalMind.org.

Hope you enjoy the book as much as I did.