PsycCRITIQUES - How Much Biology Do We Need to Understand ...

PsycCRITIQUES - How Much Biology Do We Need to Understand the Mind?

How Much Biology Do We Need to Understand the Mind? A review of The Origin of Mind: Evolution of Brain, Cognition, and General Intelligence by David C. Geary Washington, DC: American Psychological Association, 2005. 459 pp. ISBN 1-59147-181-8. $59.95

Reviewed by Gregory F. Ball

The Relation Between Biology and Psychology in the Study of Brain and Cognition Relations between psychology and biology have a checkered history. At the dawn of experimental psychology as a field in the late 19th century, this field could almost be viewed as an offshoot of biology. Darwinian ideas had a great influence on comparative psychologists, and ideas from physiology were very important to subfields of experimental psychology such as sensation and perception. The growth of psychology as an independent scientific discipline in the 20th century with the concomitant development of applied areas of psychology such as clinical or industrial/organizational psychology was associated with a near divorce between the fields. By 1950, one could reasonably observe that even many psychologists who spent their careers working with animals had little knowledge of, or interest in, biological ideas or even basic biological facts. All this started to change gradually over the course of the 20th century such that in the present day, there are many obvious connections once again between biology and psychology. For example, a substantial number of psychologists interested in animal learning now investigate the brain mechanisms of learning, often at the cellular/molecular level of analysis. Cognitive psychologists regularly investigate cognitive functioning in patients with brain damage or use modern neuroimaging methods such as functional magnetic resonance imaging to identify neural correlates of cognitive processes. These fruitful interrelations between psychology and biology are not limited to the domain of proximate causation. Some psychologists are applying Darwinian ideas to understand the organization of human social behavior and cognitive functioning, helping to place our understanding of these phenomena on a sound basis in relation to evolutionary theory. Though these examples attest to the fact that there are clear connections between the fields of psychology and biology, there are clearly still major gaps. Many subfields of psychology continue to be essentially abiological. What does the future hold? Will a psychology thoroughly consistent with biological thinking and steeped in the latest biological knowledge—but still with a focus on brain, cognition, and behavior—emerge? For some http://testing.psycinfo.com/psyccritiques/display/?artid=20050075 (1 of 3)6/20/2005 5:49:23 PM


psychologists this vision is the future, and David C. Geary is one of them.

How Might a Marriage Between Biology and Psychology Provide Us With Useful New Ideas About the Origin of Mind? The Origin of Mind: Evolution of Brain, Cognition, and General Intelligence, authored by David C. Geary, is an impressive effort to make the case for a modern interdisciplinary study of brain and cognition that views cognitive processes as biological adaptations shaped by natural selection acting on neural systems. To support his view, Geary provides the reader with an inordinate amount of foundational material. He starts with a dose of the relevant biology. The basics of natural and sexual selection are described. There is a primer on hominid evolution and evolutionary psychology. He provides a concise discussion of brain evolution and comparative cognition. Relevant ideas from cognitive science and experimental psychology are also summarized. In this case, he reviews ideas about the modular organization of cognition as well as studies on folk psychology, folk biology, and folk physics. He describes the basics of heuristics and problem solving and tells about the fundamentals of psychometrics as related to the measurement of intelligence and the concept of g (general intelligence). Many of these concise subject primers are laced with historical vignettes that help put the information in context. The background material is so extensive that at times I thought I was reviewing a series of chapters from some interesting yet idiosyncratic textbooks for courses such as introduction to psychology, animal behavior, and behavioral neuroscience. Although I enjoyed reading through most of this material, I did find myself wondering about the main argument of the book. Is all this background information necessary? At first, I was skeptical, but as I thought about the desired audience, I realized that there are relatively few potential readers, independent of their level of education, who would be sufficiently familiar with the configuration of ideas and concepts that Geary calls on to make his case. There are few courses of study in the United States or abroad in which a student could be reasonably asked in an oral examination to write out, for example, Hamilton's rule, explain the difference between Thurstone's and Spearman's concept of g, and describe the allometric equations that explain variation in brain size and body size among various vertebrate taxa. One could easily conceive of such a curriculum existing if a truly biological psychology was developed. However, that is regretfully not the case at present, so the various primers provided by Geary are necessary if he is to capture a broad audience.

How Did the Mind Evolve? What is the main argument of this book? I discern it as follows: The brain and its associated cognitive systems have been shaped by natural and sexual selection. In its simplest form, this argument is irrefutable. However, the vexing question has always been what is the functional neurobehavioral unit that has been shaped by selection? Purely physical features such as the phenotypic properties of neurons, brain nucleus size, or overall brain size, though clearly influenced by selection, do not by themselves relate specifically to cognitive or behavioral functions in a way that allows them to explain behavioral adaptations. The modularity of cognitive systems is another appealing dimension on which to think about selection acting, but these are sometimes hard to

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link clearly to variation in reproductive success. Geary argues that the fundamental neural-behavioral units that have been shaped by natural and sexual selection can be thought of in terms of systems that initiate and regulate our motivation to control all the resources that we need to attain a high degree of reproductive success. In complex societies, such as our own, this motivation to control involves the basics obviously needed for survival and reproduction by all organisms, such as food, water, essential nutrients, shelter, and mates—but also the attainment of status and social position needed to excel in socially competitive contexts. This latter point takes us firmly into the domain of human cognition and explains many cognitive biases that we have about the overall organization of cognitive processes as exemplified by our folk biology, psychology, and physics. An important point that Geary observes is that in many cases these motivation control systems do not need to be conscious and therefore are not related to human cognition as it is often considered. The lack of a need of conscious thought for many important behavioral mechanisms is no surprise to most behavioral neuroscientists who are used to complex decision making being conducted in an unconscious way. Some students of cognition and human social behavior may balk at this notion, but it is certainly supported by many studies, and it is a reasonable and useful point to make. However, our conscious or autonoetic systems, as Geary refers to them, are full of biases and structures that Geary argues can be explained in terms of the motivation to control resources of various types in a way that ultimately maximizes our individual reproductive fitness (or has in the past). This is an interesting argument that merits discussion by the cognitive neuroscience and evolutionary psychology communities and would make an excellent way to organize a seminar in brain and cognition—especially one in which the topic of interest is being considered in an evolutionary context. Geary could have spent more time describing how one would go about testing the major thesis of this book. Obviously, there are many details to his wide-ranging discussion that I cannot address in a review. However, his interpretations constitute an intriguing argument that organizes numerous data from diverse sources. Nevertheless, at times the book reads too much like an interesting way to organize our thoughts about brain and cognition rather than a text that provides us with clear hypotheses that, when tested, will provide us with new insights into the evolution of brain, cognition, and behavior. However, this comment is really just a quibble. Geary has marshaled a large amount of information, and his book is a welcome addition to the literature on biological psychology and cognition. I look forward to a future when someone writing a book such as Geary's will not feel it necessary to review quite so much basic material because he or she will be able to count on a readership that has the requisite knowledge.

PsycCRITIQUES June 22, 2005 Vol. 50, No. 25, Article 1

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