Braindance: What New Findings Reveal about Human Origins and Brain Evolution

Paleontologist Falk, an anthropology professor at the State University of New York, challenges traditional theories about the immediate ancestors of the species homo through reexamination of such hominid fossil records as the skeleton known as Lucy, unearthed by Donald Johanson in 1986, which she maintains is much more apelike than humanlike. While the rapid growth in size of the human brain has been thought to occur along with our ancestors' development of bipedalism, Falk points out that footprints of an upright species have been dated millions of years earlier than records of a large-brained human. To explain the lag, she offers a ``radiator theory'' in which the brain grew as it took on cooling functions required as the species encountered greater exposure to sunlight. Current neurological studies and fossil research are combined as the author discusses brain lateralization and gender differences in brain organization. Falk makes much of the travails that she has encountered in proposing ideas that oppose established thought, to the detriment of her frequently intriguing account. (Feb.)