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The brain of modern humans is an evolutionary and developmental outlier: At birth, it has the size of an adult chimpanzee brain and expands by a factor of 2 during the first postnatal year. Large neonatal brain size and rapid initial growth contrast with slow maturation, which extends well into adolescence. When, how, and why this peculiar pattern of brain ontogeny evolved and how it is correlated with structural changes in the brain are key questions of paleoanthropology. Because brains and their ontogenies do not fossilize, indirect evidence from fossil hominin endocasts needs to be combined with evidence from modern humans and our closest living relatives, the great apes. New fossil finds permit a denser sampling of hominin endocranial morphologies along ontogenetic and evolutionary time lines. New brain imaging methods provide the basis for quantifying endocast-brain relationships and tracking endocranial and brain growth and development noninvasively. Combining this evidence with ever-more detailed knowledge about actual and fossil "brain genes," we are now beginning to understand how brain ontogeny and structure were modified during human evolution and what the adaptive significance of these modifications may have been.

One of the major difficulties that commonly arises during the analysis of fossils is the lack of extensive samples and the incompleteness of individual specimens. Even by paleontological standards, hominid fossils are extremely rare objects, and the principal difficulties encountered during the analysis of fossil morphology can be expected to multiply in this special case. Given the need to gain a maximum of information from a minimum of material evidence, one of the main challenges of paleoanthropology is to enhance the investigative power of morphometric methods while minimizing the invasiveness of methods used for data acquisition. A computational approach to these problems has three different aspects. The historically most recent and therefore most evident aspect of computation is that of hardware and software, the combination of which (in the form of computers) permits acquisition, manipulation, and processing of large volumes of data. The second aspect is morphometry, i.e., the definition and quantification of morphological parameters and their multivariate analysis. The third aspect concerns modeling, which in its widest sense denotes the development of mathematical concepts to operationalize and quantify the content of biological hypotheses. The primary aim of this contribution consists in providing a “taxonomy” of the computational tools and concepts that are currently available to tackle morphological problems in paleoanthropology. The second aim is to show that there are mutual links between the three aspects of computation. In paleoanthropology, as in every area of the natural sciences, data acquisition, definition and measurement of parameters, and formation of hypotheses influence one another.

Paleoanthropologists are confronted by a steadily growing number of fossil specimens exhibiting diversity in both apparent morphology and state of preservation. Studying this material to answer phylogenetic and functional questions requires extensive qualitative assessment accompanied by quantitative evaluation of large volumes of data. Over the past decade, major new developments in both respects have been made possible through the advent of medical imaging technologies, most notably computer tomography (CT), and through concomitant progress in computer graphics technology. In paleoanthropology, these techniques offer noninvasive tools for visualization of inaccessible regions of the skeleton, computer-assisted reconstruction of fragmentary fossil specimens, and morphometric or biomechanical analysis of data derived from CT images. A series of CT based studies has already yielded new insights into character differences between fossil hominid species. © 1998 Wiley-Liss, Inc.