Biological Life Course

Incremental dentine analysis utilizes tissue that does not remodel and that permits comparison, at the same age, of those who survived infancy with those who did not at high temporal resolution. Here, we present a pilot study of teeth from a 19th-century cemetery in London, comparing the merits of two methods of obtaining dentine increments for subsequent isotope determination. Covariation in d13C and d15N values suggests that even small variations have a physiological basis. We show that high-resolution intra-dentine isotope profiles can pinpoint short-duration events such as dietary change or nutritional deprivation in the juvenile years of life.

"The primordial aim of palaeoanthropological research in Africa and Asia was to answer these questions: Who is man ancestor? Is there an actual separation between man and his known direct ancestor? Between God and animal, man should have his place with the word "hominity".

The extreme variation in morphology and size in Australopithecus afarensis (Hadar, Laetoli and Garusi hominids) has to say about the evolution leading to hominity. Hominid fossils discoveries have provided several australopithecine species, from 1 to 5 million years (Myr), with some human characteristics. The record is still fragmentary and there are many morphological gaps, however comparison of the fossils establishs a divergence of forms from character displacement with time that can be attibuted to an evolutionary pressure on successive and competing species.
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The evolution of the cerebral capacities of humans, from the first hominids to Modern Humans, is at the heart of our interrogations. How can we explain the fact that only hominids seem to have developed the capacity for technical invention, in contrast to our closest relatives the great apes? The archaeological data allow us to observe this phenomenon but offer very little in the way of a response to this question. By examining the possible contributions of other disciplines, particularly in the cognitive and neuropsychological sciences, we can ask if there exists a cause and effect relationship between the following phenomena: - The archaeological data indicate that the technical inventions realized throughout prehistory are increasingly frequent and complex from the first hominids to Modern Humans; - The cognitive perspective seems to indicate that the processes of analogical reasoning are increasingly frequent through time, either for "statistical" reasons (a greater population density leads to a greater probability of the meeting of two ideas), or for cognitive reasons; - Finally, the paleoanthropological data show that current neurological conditions developed progressively with the frontal lobes and prefrontal cortex becoming more and more accentuated from the first hominids to Modern Humans. We will explore here the possible contribution resulting from a confrontation of these different disciplines.

ABSTRACT Event history calendar (EHC) methods have received increasing attention from the life-course surveys that have been used in recent years. According to the literature, the EHC provides high-quality data in retrospective surveys because it replicates the autobiographical memory retrieval processes. EHC interviewing is processed through the visual display of individual life events, phases and transitions on a chronological calendar grid, which allows respondents to effectively link events as well as to identify and correct possible dating errors. Moreover, interactive interviewing facilitates the retrieval mechanism. In this study, we test whether the absence of an interviewer and/or interactive interviewing are associated with a reduction in data quality. This aspect is particularly relevant for surveys, as the absence of the interviewer would allow the implementation of EHC methods in self-administered questionnaires. In Study 1, an experimental design compared the results of self-administered paper-and-pencil EHCs in the presence and absence of an interviewer. In Study 2, a quasi-experimental approach compared the results of an interactive EHC interview with those of a self-administered paper-and-pencil EHC. Neither of these studies showed systematic differences between self-administered and interviewer-administered EHCs. The self-administered mode performs better when the instructions and layout design of the questionnaire are clear and detailed. Our findings suggest that the visual properties of the EHC could be a sufficient condition for collecting good retrospective data in the self-administered mode once the initial burden of the task is overcome.

Just how strapping was KNM-WT 15000? Previous estimates suggest that Nariokotome Boy would have attained an adult stature of 185 cm (~6’1”) and body mass of 68 kg (~150 lbs). These adult estimates were based on modern human models that incorporated a long, extended period of growth and a fully-developed adolescent growth spurt. However, recent fossil discoveries, improved research methods, and new insights into human and non-human primate ontogeny suggest that KNM-WT 15000 matured faster than a modern human, calling into question previous estimates of adult size. To reassess adult stature and body mass in KNM-WT 15000, we modified chimpanzee and modern human growth curves to create a number of hypothetical H. erectus velocity curves. We calculated the amount of growth remaining at death using these curves, and increased juvenile stature and body mass estimates accordingly. The curves that most accurately match the series of events in KNM-WT 15000’s life history produced estimates both shorter (163 cm, ~5’4”) and smaller (56 kg, ~123 lbs) than previously calculated. Bootstrap analyses confirm that our new estimates reduce the range of variation in H. erectus, so that Nariokotome Boy may have been strapping as a youth, but his estimated adult size falls in line with other H. erectus specimens. The implications of these new estimates for interpretations of encephalization, physiology, growth and development, behavior and sexual dimorphism in H. erectus change our understanding of the transition from australopiths to later Homo.