PhD project: An examination of enamel microevolution over the last 2000 years of human history
Christopher’s PhD research involves looking into growth rates, interior structures and morphology of permanent human enamel of individuals from time periods spanning the last 2000 years of human history through histological methods.
He is currently working with over half a dozen human populations, all excavated or sourced from various locations in Britain. These remains represent past human societies which date from multiple historic time periods, notably those from the Roman, Anglo-Saxon, Early Medieval and Late Medieval periods, alongside clinical modern samples. Christopher’s research involves the extensive study of incisors, canines and molars, from both the mandible and maxilla, from each of the listed populations.
Prior to starting his PhD, Christopher completed a BSc in Biological Anthropology (2:1) from the University of Kent and an MSc in Human Osteology and Funerary Archaeology (Distinction) from the University of Sheffield. His BSc dissertation involved studying the effects of stress on juvenile skeletal development. His MSc thesis focused on creating a method of determining sex from juvenile skeletal remains from permanent molars: he is currently working on writing this research up for publication.
- Aris, C. (2019). The Histological Paradox: Methodology and Efficacy of Dental Sectioning. Papers from the Institute of Archaeology. In Review
Aris, C., Nystrom, P. and Craig-Atkins, E. (2018). A new multivariate method for determining sex of immature human remains using the maxillary first molar. American Journal of Physical Anthropology [Online] 167:672-683. Available at: https://doi.org/10.1002/ajpa.23695.Objectives: This study investigated the use of sexually dimorphic metrics of the first permanent
maxillary molar (M1) to determine sex in adult and immature individuals within and between
Methods: Ten M1 dimensions were measured in 91 adults (19–55 years) and 58 immatures (5–-
18 years) from two English populations, one of documented sex (Spitalfields crypt) and another
of morphologically-assigned sex (Black Gate). Preliminary statistical analysis was undertaken to
explore bilateral differences and variation by age and sex, followed by multivariate analyses to
predict sex from dental metrics.
Results: Both cross-validated linear discriminant analysis and binary logistic regression predicted
biological sex consistent with known sex in 94.6% of adults and 90.9% of immatures. When
functions extracted from the Spitalfields data were used to assign sex to Black Gate adults, consistency
with morphological sex varied from 83.3% to 57.7%. A new function developed on
Black Gate resulted in only a 4.8% increase in maximum accuracy but reduced bias. The immature
cohort comprised 19 (52.8%) males and 17 (47.2%) females.
Conclusions: This study demonstrates substantial sexual dimorphism in a single tooth which is
commonly preserved in archaeological and forensic contexts. It successfully assigns biological
sex to immatures from 5 years of age with substantially greater accuracy than any other morphological
or metric method. We suggest that accurate cross-population functions based on
dentition require a trade-off between accuracy and applicability, and that functions extracted
from populations of documented sex can be used to assign sex to other archaeological and