WHEN DID HUMANS FIRST ARRIVE IN GREATER AUSTRALIA AND WHY IS IT IMPORTANT TO KNOW

Until recently, archeologists have generally agreed that modern humans arrived on Australia and its continental islands, New Guinea and Tasm ania (collectively, Greater Australia), about 35,000 to 40,000 years a go,(1) a time range that is consistent with evidence of their first ap pearance elsewhere in the Old World well outside Africa.(2,3) Over the past decade, however, this consensus has been eroded, first by dates of 50,000 to 60,000 years from two sites in Arnhem Land(4,5) and then, dramatically, by dates of 116,000 to 176,000 years from a third site on the eastern margin of the nearby Kimberley region.(6) If accurate, these dates require significant changes in current ideas, not just abo ut the initial colonization of Australia, but about the entire chronol ogy of human evolution in the late Middle and early Upper Pleistocene. Either fully modern humans were present well outside Africa at a surp risingly early date or the behavioral capabilities long thought to be uniquely theirs were also associated, at least to some degree, with ot her hominids. Deciding whether these dates are accurate and associated with definite evidence of human activity thus becomes critically impo rtant. We think there are good reasons to be skeptical, not only on th e basis of the dates and their alleged associations, but because of th eir mismatch with established sequences, both in Greater Australia and elsewhere. Until these issues are resolved, adjusting the broader glo bal picture to accommodate these early dates is premature.