Review of The evolution of lateral asymmetries, language, tool use, and intellect and The lopsided ape: Evolution of the generative mind. (1993)

We have come to think of the left cerebral hemisphere as being and th e right hemisphere as being holistic. Just as there is an analytic - holistic distinct ion in functional brain asymmetry, there is also an analytic - holistic distinction in books, and these two books by Bradshaw and Rogers and by Corballis represent the ends of this continuum.Why should one wish to write a scientific treatise in the first place? Certainly there is far more money in introductory textbooks. I suppose there are two main motivations. First of all, one has a good idea, and would like to communicate it to the world. Corballis has the id ea that the human capacity to generate novel language arose in an evolutionary sense from th e ability to combine complex gestures. His book is an attempt to flesh out and buttress this idea. A second reason is that one knows a great deal about the subject and hopes that, by writi ng a book on the topic, all of this factual information will come together in a meaningful way. B radshaw and Rogers know a great deal about laterality in both human and non - human species, and their volume brings together this knowledge in a well - organized fashion. In some sen se, then, the Corballis volume is holistic and the Bradshaw and Rogers volume is analytic.The trouble with an idea or holistic book is that most ideas do not require a whole book in which to be expressed, and therefore are frequently first loosed on the world in much shorter form (Corballis, 1989). A dangerous consequence of this is that the main thesis of the book no longer seems novel, and much of the other material seems to be padding, however witty and entertaining this padding may be.Conversely, the problem with a survey or analytic book is that it is sometimes very hard to see where it is going. Because the authors hope that the conceptual novelty will be an emergent property, the structure is based on some underlying conception of how the topic should be organized - in the case of Bradshaw and Rogers, various classifications of phyla , order, and species - and the major issues are left to come out by themselves.I suspect that there will be quite different responses to these different types of book. Corballis is a lucid and humorous writer, and his volume makes easy reading. Bradshaw and Rogers are thorough rather than entertaining, and their volume often makes rather slow read ing. I would guess that many more people will read the Corballis volume from beginning to end , and remember the key points in it. On the other hand, I am also prepared to believe that there will be a small number of people, active researchers in the field, who will cherish t he Bradshaw and Rogers volume, keep it close at hand, and refer to it for many years to come. ( What do we know about laterality in the chicken/mouse/baboon? Bradshaw and Rogers will have something to say about that.)Bradshaw and Rogers see functional asymmetry everywhere, from fossil trilobites of the Cambrian period, half a billion years ago, to the more obvious human asymmetries of language and visuospatial function. Their book provides a thorough review of behavioural and morphological asymmetries in a wide variety of species, with a concentration on birds, rodents, and primates. Bradshaw and Rogers argue that there are not only behavioural and morphological asymmetries in many different species, but that these are frequently influenced by environmental factors and often show sex differences. Their basic message appears to be that t here have long been many different forms of functional asymmetry, and that the present state of affairs in homo sapiens sapiens is the end product of the coevolution of many different interact ing factors.There is, for example, evidence for the lateralization to the left hemisphere of the production of species - relevant vocalizations in the songbird, for the processing of ultra sonic calls from their pups by mother mice, and for the perception of species - specific vocaliza tions by the Japanese macaque. …