On the evolution of handedness: A speculative analysis of Darwin's views and a review of early studies of handedness in "the nearest allies of man"

Scientists today who seek; clues into the evolutionary origins of human han dedness make extensive use of evidence from comparative studies, that is, s tudies that ask whether handedness occurs in other species, especially apes and monkeys, as the Darwinian principle of continuity would seem to imply, or whether it is uniquely human. Early investigations had the same goal an d drew on much the same hind of evidence. In this article, I review studies of animal handedness in the period before 1859, when Darwin in published O n the Origin of Species, and afterward, through the ist decade of the 20th century. Inasmuch as Darwin's published writings contain hardly any stateme nts about handedness and none at all about its evolution and continuity acr oss species, I also speculate about what Darwin himself might have said on the subject. To do this, I draw on his statements on related matters, such as the form and structure of the hand and the transition from a quadrupedal to bipedal stance, on other writers' reports and opinions about handedness with which he was familiar or likely to have been familiar, and finally, o n clues from his own and only statement about animal handedness in an unpub lished letter. I conclude by asking whether and how early investigators, la cking any statement by Darwin on the evolution of handedness, invoked his t heory of evolution and his views on related matters in the interpretation o f their findings. (C) 2000 Academic Press.