The Accidental Mind: How Brain Evolution Has Given Us Love, Memory, Dreams, and God

by David J. Linden

Book Overview

You've probably seen it before: a human brain dramatically lit from the side, the camera circling it like a helicopter shot of Stonehenge, and a modulated baritone voice exalting the brain's elegant design in reverent tones.

To which this book says: Pure nonsense. In a work at once deeply learned and wonderfully accessible, the neuroscientist David Linden counters the widespread assumption that the brain is a paragon of design--and in its...

• Format: Paperback
• Language: English
• ISBN: 0674030583
• ISBN13: 9780674030589
• Release Date: December 2008
• Publisher: Belknap Press
• Length: 288 Pages
• Weight: 0.93 lbs.
• Dimensions: 0.8" x 7.4" x 9.2"

Customer Reviews

Our mental ice cream cone

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

Nicely done, accessible account of the human brain

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.

Great story!

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.

Will change the way you think about things

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.