Internet Archaeol.8. Virtual 3-D Facial Reconstruction

1. Introduction

The face is the most fundamental cognitive feature of individual identity. It is because of this that, in archaeology, facial reconstruction has the power to create empathy with people who lived long ago and so enjoys continued popularity in public archaeology (Prag and Neave 1997), featuring frequently in museum exhibitions and television programmes.

It is a common misconception that facial reconstructions are exact likenesses of the individual during life. A cursory examination of the skull reveals that the relationship between skull contour and facial appearance is not straightforward. On the forehead, the margins of the eyes, the cheek bones, the bridge of the nose, above the lips and on the chin, facial shape is quite closely related to skull contour. But the shape of the eyes and eye lids, the tip of the nose and the lips cannot be predicted from the skull and these are important features in facial recognition. Furthermore, hair style and colour, skin colour, facial hair, scars, tattoos, piercings, jewellery, clothing, cosmetic make-up, spectacles, and numerous other aspects of facial appearance cannot be determined from the skull. Estimates of age, height, build and even sex are imprecise, and degrees of obesity and of ageing for example cannot be predicted. Ethnic affiliation can only be estimated with weak statistical confidence and even then only for that which has evolved as a consequence of continental scale biodiversity and history such as 'Black, African or African-Caribbean', 'Caucasoid', and so on. The measurements used in facial reconstruction are tissue depths accumulated piecemeal over the course of more than a century and collected from cadavers. The individual in death bears limited resemblance to the individual during life post-mortem changes and gravity affect tissue depth measurements. The datasets are small, measurements are imprecise and are taken from only twenty or so landmarks. There is no way of knowing, when applying the mean tissue depths from a dataset, that the person is a 'mean' member of the population. All in all, a reasonable resemblance is the best that can generally be hoped for from facial reconstruction and even this seems something of an achievement.

The application of facial reconstruction in the investigation of homicides and missing persons cases has established the technique as viable and worthwhile in cases where no other means of individual identification is available. The success rate may be less than 50%, but facial reconstruction can deliver success in terms of an identification when all other hope is lost. Facial reconstruction cannot be used to determine identity it is far too imprecise, but it can be used to generate a list of names which can be refined by a process of elimination until identity can be firmly established from dental records or DNA profiling.

Traditional 'plastic' reconstruction carried out using clay is slow. In an emergency a reconstruction can be completed in a day, but will normally take up to a week. Repeatability is poor. Reconstructions will vary even when repeated by the same practitioner and will differ widely between practitioners. There can even be a tendency to incorporate one's own facial features into a reconstruction. Reconstruction relies on a substantial degree of dexterity and artistic skill, as well as a knowledge of anatomy, and physical and dental anthropology. Amendments to the reconstruction to account for ageing or obesity, for example, mean several hours further work in the studio and if the original outcome is to be kept for posterity a copy must be made. Further time constraints are introduced by the simple logistics of bringing skull and practitioner together in national and international investigations. Costs can run into thousands of pounds. Such costs can be encountered in archaeological reconstructions too.