Houston Sarah-Kelly, Brits Desiré, Myburgh Jolandie, Liebenberg Leandi
Department of Anatomy, University of Pretoria, Pretoria, South Africa.
Human Variation and Identification Research Unit, School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, South Africa.
Int J Legal Med. 2025 Aug 6. doi: 10.1007/s00414-025-03568-1.
The five sexually dimorphic traits of the skull described by Walker are frequently employed in skeletal analyses for sex estimation. Previous research has highlighted various changes in the craniofacial complex associated with advancing age, as cranial remodelling persists into adulthood. Age has been recognised as one potential factor contributing to misclassification when using the Walker traits. This study aimed to evaluate the influence of age on the expression of sexually dimorphic cranial traits and the impact of that influence on sex estimation in a South African sample. The traits were scored on a sample of 453 skulls between 14 and 108 years of age with an equal sex distribution. Only the nuchal crest exhibited significant differences in score distributions among the females in the sample, indicating differences between individuals younger than 40 years and those older than 40 years. Classification models showed a slight increase in accuracy for younger individuals when age-specific standards were applied, while accuracy for older individuals decreased slightly. However, the difference in accuracy with age-specific standards was comparable to accuracies obtained with all ages pooled. The results suggest age did not have as substantial an impact on trait expression as population affinity, and prior knowledge of age did not significantly influence the accuracy of the method. Thus, the pre-selection of age before the estimation of sex using the Walker traits is not currently necessary when conducting skeletal analyses in a contemporary South African population. However, the use of population-specific standards is paramount to more accurate classification.
沃克所描述的颅骨的五个性别二态性特征经常被用于骨骼分析以进行性别估计。先前的研究强调了随着年龄增长颅面复合体发生的各种变化，因为颅骨重塑会持续到成年期。年龄已被认为是使用沃克特征时导致错误分类的一个潜在因素。本研究旨在评估年龄对性别二态性颅骨特征表达的影响以及这种影响对南非样本中性别估计的作用。对453个年龄在14至108岁之间、性别分布均等的颅骨样本的这些特征进行了评分。在样本中的女性中，只有项嵴在评分分布上表现出显著差异，表明40岁以下个体与40岁以上个体之间存在差异。分类模型显示，当应用特定年龄标准时，年轻个体的准确率略有提高，而年长个体的准确率略有下降。然而，采用特定年龄标准时准确率的差异与所有年龄合并计算时获得的准确率相当。结果表明，年龄对特征表达的影响不如群体亲缘关系大，并且年龄的先验知识并未显著影响该方法的准确性。因此，在当代南非人群中进行骨骼分析时，目前在使用沃克特征估计性别之前预先选择年龄并非必要。然而，使用特定群体标准对于更准确的分类至关重要。
