General areas of interest
Evolution of hominin asymmetry and lateralisation, human handedness, functional morphology (non-human primate and human), comparative osteological methods, the role of the hands in hominin lithic manufacture and Upper Palaeolithic parietal art
I am currently designing a future project based on the outcomes from my PhD research (see below). I aim to extend this research to explore in more detail the nature of bilateral asymmetry in non-human primate species and investigate the relationship between recognised patterns of behaviour and corresponding morphological modifications. I am planning to collect extensive skeletal data across a large number of ape and monkey species to test the hypothesis that varying levels of tool use and functional lateralisation in non-human primates will be reflected in differing upper limb asymmetry profiles across species. This data can then be compared with the large corpus of behavioural data that has been collected on non-human primates.
I am also developing my interests in functional morphology more generally and am currently involved with a project at the University of Southampton with Dr Graeme Earl that is exploring the reconstruction of hominin gait from Pleistocene footprints and the placement of these individuals within a virtual environment (see profile).
research was motivated by my interest in 'handedness', the population-level trend for preferential use of one hand other the other across a wide range of tasks. Such a strong preference for the use of one hand, typically the right hand (in approx. 70 - 90% of those studied) appears to be unique to modern humans, with the nature of non-human handedness currently a topic of debate.
The uniqueness of the human condition prompted an interest in the evolution of handedness within the hominin lineage leading to Homo sapiens. Hand preference is commonly determined through examination of upper limb bilateral asymmetry and development of areas of muscle attachment to bone (often referred to as musculoskeletal stress markers, MSM). However, the congruency of various approaches to quantifying asymmetry has been largely neglected, with researchers often focusing on one technique or a single measurement. Additionally, the focus of this research has been on the humerus, to the exclusion of the bones of the hand. I was therefore interested in the impact of methodological choice and anatomical region of study on asymmetry profiles and its potential impact on determination of hand preferences in archaeological samples.
To that end, my thesis was entitled 'The
of Bilateral Asymmetry in the Hands and Humeri: A Methodological
Comparison' and examined asymmetry profiles generated from a range of measurements taken from the metacarpals, phalanges and humeri, using both metric and MSM methods, on a large sample of modern humans (from the Medieval Islamic cemetery of Ecija, southern Spain and the Greenwich Naval Hospital Cemetery site, London) , chimpanzees and gorillas (form the Powell-Cotton collection).
Analysis found that in fact metric and MSM methods differed in terms of the amount and direction of asymmetry they found, with MSM tending to under-estimate the amount of asymmetry present relative to metric measurements. Hand and humeri measurements also differed in terms of asymmetry magnitude and direction, with these differences varying between samples, but also within the hand (i.e. within and between metacarpals and between phalanges) and the humerus.
Together, these findings (a) highlight the impact that methodological choices can have on our understanding of upper limb asymmetry and behavioural lateralisation and caution against the use of single skeletal elements for assessing asymmetry, (b) no longer support the exclusion of the hand from asymmetry research and suggest that our understanding of this trait has been compromised by the previous focus on the bones of the arm, and (c) indicate the presence of functional asymmetry within the chimpanzee and gorilla samples studied, contradicting commonly-held assumptions about the functional morphology of the great ape upper limb (but supporting the recent findings of Sarringhaus et al., 2005).
This research was conducted within the Centre for the Archaeology of Human Origins (CAHO - http://www.soton.ac.uk/archaeology/caho/about.html) and supervised by Dr Sonia Zakrzewski. It was funded in part by the British Academy Centenary Project - From Lucy to Language: The Archaeology of the Social Brain (http://www.liv.ac.uk/lucy2003/) and a British Association for Biological Anthropology and Osteoarchaeology (BABAO) Small Research Project Grant (http://www.babao.org.uk/index/awards)
Please contact me (see contact page) if you would like a pdf copy of the dissertation.