Vladimir Miskovic 2006-07-07
2 of 2 people found the following review helpful:
In the 1960's, Michael Gazzaniga and Roger Sperry (the Nobel laureate) undertook a series of pioneering and innovative studies of human split-brain patients. These were people in whom the corpus callosum, a bundle of nerve fibers which links the left and right cerebral hemispheres, had to be excised for medical reasons. Gazzaniga and Sperry went on to make many startling discoveries about these patients. One of the key discoveries from these and subsequent studies was that one of the functions of the left hemisphere is to continually provide an interpretive framework for our experiences. Much of "The Mind's Past" concerns the issue of how this left brain device (Gazzaniga dubs it "the interpreter") provides us with a convenient fiction: that we are autonomous agents, independent selves, with free will, fully in control and capable of determining our own actions. Gazzaniga sets out to show the reader how that interpreter is superimposed over the operations of a multitude of other brain devices, which perform their work `behind the scenes' so to speak; thus, "the brain knows before `you' do".
Gazzaniga's central thesis is this: the brain comes filled with a variety of built-in gadgets (what Steven Pinker would call `organs of computation'). These specialized modules are products of natural selection (the only purely physical process capable of generating complex design) and they handle the kinds of problems that must be solved in order to get around in the world, to survive and ultimately to procreate. Fortunately for us, this staggering multitude of processes goes on outside of our awareness - the gadgets work on automatic pilot. Approximately 98% of the brain's operations are not consciously accessible, though we can certainly be aware when some of these devices malfunction as when, for example, we lose the ability to detect motion in the world around us. The brain's computational organs just churn away, working on the basis of given assumptions (some of these assumptions can be made explicit with clever visual illusions) and they take care of the main tasks of life. They have done this for thousands of years.
The interpreter, then, is a device that sits atop of the information processing hierarchy; on top of a hierarchy of sub-symbolic information processing stages. It can make us aware of some of the output of those automatic functions - sometimes making gross errors in the process. Gazzaniga's discussion of the interpreter and his examples of the extents to which this narrative-constructing device is ready to impose order on events is the most interesting part of the book. His own research with split-brain patients informs a great deal of this discussion.
Gazzaniga cites a plethora of research findings to bolster his case, including some of the big findings that have emerged from the fields of evolutionary psychology, cognitive neuroscience and developmental neurobiology. He also takes issue with the more extreme versions of connectionism which view the brain as a general purpose problem solver. According to that view it is the environment, via massive backward propagation, which calibrates appropriate outputs to relevant inputs (i.e., the organism learns appropriate ways of responding to categories of environmental events). In contrast to this 'tabula rasa' theory, Gazzaniga sides with the main tenet of evolutionary psychology: the structure of the problem space comes embedded in brains in a variety of modules -- complexity is a given not a construction.
Unfortunately, the book has several drawbacks. For one, the writing is a bit dry in some places and this makes reading the book, despite its brevity, a laborious process at times. Also, the research which is covered often involves complex experimental designs which resist being summarized in a few paragraphs - and while the intention was to present the basic implications, some times these are difficult to really grasp without the relevant context and background. Another problem is that the book vacillates between seeming to assume at least some familiarity with the field at one point, but then over-simplifying the issues at another end. All in all, a somewhat inconsistent effort, that does not cover much in terms of new material.
