Perceptions of the emergence and spread of modern humans have changed recently through the reanalysis of fossils, an improved geochronological framework, and the discovery of a few specimens. Early modern humans in various portions of the Old World exhibit complex and varying mosaics of archaic, modern, and regional morphological characteristics. On the basis of this pattern, in conjunction with the emerging chronology of the earliest modern humans, the paleontological data indicate an assimilation model for modern human origins, in which the earliest modern humans emerged in eastern Africa, dispersed briefly into southwestern Asia, and then subsequently spread into the remainder of Africa and southern Asia, eventually into higher latitude Eurasia. The earliest modern humans outside of the core area of eastern Africa can be understood only if a variable degree of admixture with regional groups of late archaic humans occurred. Current and expected fossil and molecular data are unlikely to illuminate the degree of assimilation that took place in most regions of the Old World. However, the current chronological and phylogenetic framework provides the basis for ongoing investigation of the nature of this Late Pleistocene transitional period.
