This is an investigation into the relative rates and patterns of dental mineralization in Upper Pleistocene fossil hominids (Neanderthals and early modern humans) compared with three recent human geographic populations. Using a standard scoring system, frequency distributions of the various stages of development that any tooth displays relative to specified states of development of a "reference" tooth will be derived for the recent human samples. These distributions will be compared to determine whether significant differences exist in relative dental calcification rates and patterns among recent human samples. These recent human data will provide the necessary background for assessing the nature and extent of differences between recent humans and Upper Pleistocene fossil hominids in relative dental development, so that any differences in overall maturation rates can be assessed. A major gap in our understanding of the difference between Neanderthals and recent humans is a lack of knowledge of their dental development. We know that modern humans have extremely delayed dental maturation, and there is strong evidence that the earliest hominids had a much more rapid rate of dental development. Rapid dental development implies a shorter developmental period with implications for the timing of behavioral maturation. Did the shift occur before or after the Neanderthals? Neanderthals have adult brain sizes and overall body sizes similar to those of modern humans. But, did they mature at the same time and rate? This study will assist in understanding possible differences in the life history of modern humans and the Neanderthals.