If there is one personality trait that is bred into scientists, it surely is caution in making broad claims. The broader the claim, the more likely it will be met with resistance. This caution often results in hyper-specialization because there is safety in staying in the comfortable boundaries of one's specialty.



Yet, at the same time, the broader the claim, the greater a theory's potential explanatory and predictive power. And, only broad and wide-ranging theories can ever aspire to bridge the islands of specialties and sub-specialties. Darwin's theory of evolution by natural selection is so powerful precisely because of its wide-ranging explanatory and predictive power. Elegantly simple, the theory of evolution by natural selection has quite simply brought order to the biological sciences.



The premise of Dr. Previc's "The Dopaminergic Mind in Human Evolution and History" has the character of such a wide-ranging, unifying theory. In fact, it has many of the qualities of a "theory of everything"--connecting evolutionary psychology, neuroscience, personality psychology, and other disciplines with a singular connecting thread. That thread is "dopamine"--the most studied neurotransmitter.



Briefly, Dr. Previc presents the provocative theory that approximately 80,000 years ago, high levels of dopamine led to the profound developmental leaps that most set modern man apart from his human and primate relatives. To do so, he follows the thread of dopamine through the critical cognitive skills of motor programming, working memory, cognitive flexibility, abstract representations, temporal analysis/sequencing, and generativity/creativivity.



While, according to Previc, dopamine has been critical to the development of advanced human intelligence and language, it is possible to have too much of a good thing. In fact, Previc links an excess of dopamine to such individual disorders as autism (shades of Simon Baron-Cohen's "extreme male brain") , schizophrenia and obsessive compulsive disorder--and to such social dysfunctions as "endless wars and conquests, alienation from the land, stratification of society, inequality between the sexes, a reduction of leisure time, increased detachment and even alienation from our fellow human, increased mental illness, and more recently, serious environmental degradation."



Personally, I was most intrigued by Dr. Previc's speculations on the effect of substantial increases in brain dopamine on the personalities of well-known historic figures. In a chapter dedicated to what he calls the "Dopaminergic Personality in History", Previc describes how the lives of Alexander the Great, Christopher Columbus, Isaac Newton, Napoleon Bonaparte, and Albert Einstein evidence the influence of high levels of dopamine. According to Previc, this personality is characterized by a high degree of intelligence, a sense of personal destiny, a religious/cosmic preoccupation, and enormous focus (obsession) with achieving supreme goals and conquests, an emotional detachment that in many cases leads to ruthlessness, and a risk-taking mentality that can lead to consequences ranging from merely embarrassing to the outright disastrous.



The "dopaminergic society" is essentially the dopaminergic personality writ large. It is a extremely goal-oriented society. It is fast-paced and even manic "given that dopamine is known to increase activity levels, speed up our internal clocks and create a preference for novel over unchanging environments." In the same way that high dopamine individuals lack empathy and exhibit a more masculine behavioral style, dopaminergic societies are "typified by more conquest, competition, and aggression than nurturance and communality." In a such societies high dopamine individuals thrive, and through their influence, these individuals in turn increase the dopaminergic qualities of society.



Dr. Previc concludes his book with two chapters that offer prescriptions for addressing what he calls the "hyperdopaminergic syndrome"--non-adaptive high levels of dopamine.



Dr. Previc is a research scientist, and there is no mistaking that this book is steeped in the language of neuroscience. The book is somewhere in between the type of explication you would see in a science journal article and a book intended for a wider audience of people interested in developments in neuroscience. For the non-scientist, it is a challenging but not dauntingly inaccessible book. I suspect that those scientists and non-scientists who have an interest in evolutionary psychology, personality psychology and neuroscience will be the most intrigued by "The Dopaminergic Mind in Evolution and History."



Previc's claims are broad and thought provoking. If true, I suspect that the theory of the dopaminergic mind will have wide-ranging explanatory and predictive power. If wrong, the theory is still refreshingly thought provoking, and is an exemplar of the kind of bold theorizing that should be welcomed in the sciences in the interest of bridging the safe islands of specialization that have arisen with the overwhelming increase in scientific knowledge. If one thing characterizes this book it is a powerful impulse to build these bridges. I thoroughly enjoyed reading along as Dr. Previc wove his dopamine thread through such seemingly disconnected islands as testosterone, yin yang, war, brain lateralization, Napoleon's personality, mental illness, and hunter gatherer tribes.



Ironically, if Previc is correct, it is dopamine itself that makes possible the intelligence to identify the dangers of the "too much of a good thing" that is dopamine "gone wild."



(My only major complaint is that this 200 some page book was priced by Cambridge University Press for the library market. I think it should have been priced for a broader market. Hopefully they will consider repricing the book or doing a paperback edition in the near future to eliminate any resistance prospective readers may have to getting this important book.)