The Brain in Hominid Evolution

613 one of the indispensible reference sources for anyone interested in the art or science of human genetics, attests to both the great breadth of knowledge and the enormous energy of its author. Owners of previous editions will continue to marvel at the utility of this new one. Wlhile Sir William Osler statedl that "the desire to take medicine is one feature which (listinguislhes man from the lower animals," most people would differentiate these categories more directly by comparing brain "potential" and by cul-ttural and nonctultural abilities. The relationslhip of brain evolution and be-lhavioral clhanges were (lisctussed by Dr. this book is based. Mutichi more than a revised, polislhe(d lecture, lhowever, Dr. Tobias' book is a (lefinitive study of the metho(ds, results, and implications of the study of endocranial capacity and its correlation with behavior patterns. The concluisions are of major importance to the (liverse groups studying behavior and learning: archeologists, anthropologists, and psychiatrists, to name a few. Dr. Tobias begins by discussinig whetlher there is any reliable means of mneastur-ilig brain evolution. The effects of age of specimen, species differences, andl anatomic variationis (e.g., (lural and ventricular voltumes) are considered. Endo-cranial capacity is accepted an(I a sample calculation is performed to show all the factors considerecl. The remaindler of the first portion of the text analyses in detail each of the hominid species, giving data on in(lividual samples as well as average figures. Included here are corrections and recent developments presented for the first time [e.g., reevaltuation of the endocranial capacity of Homo erectus I (Indonesia), an(l (lata on H. erectus VIII (discovered 30 March 1971)], as well as several concepts not considered previously (e.g., the correlation of brain weigiht andl body heiglht). In the remaindler of the text, Dr. Tobias reviews the accepted capabilities of eaclh h-ominid species and tries to relate this to neural system evolution. He states that "moclern man-whetlher in Africa or Europe would seem to lhave some-wlhat lower mean brain sizes than his forebears of the Upper Pleistocene." Thlls, the final brain volume in H. e-ectuis apparently reached a point beyond whiclh further increase is no longer necessary for "humanity"; why then has there been a further increase of 650%o in endocranial capacity? Tobias expands on G. S. Krantz's thesis that this increase in final size (but maintaining a small initial size) causes a capacity of 750 cm3 to occur much earlier (1 year …