As an important topic in Human Osteoarchaeology, the spatial-temporal evolution of Holocene populations is of great significance for exploring migration and environmental adaptations. Previous studies have focused on the craniofacial micro-evolutionary changes within Chinese Holocene populations by comparing groups from different eras. However, different methods of defining epochs can directly affect how researchers interpret and describe their observations and results. Moreover, this approach subjectively divides the continuous changes in human traits. It is worth noting that currently, there are few empirical studies exploring the internal mechanisms of temporal change.

In this paper, 1159 craniums (731 males and 428 females) unearthed from 84 archaeological sites or cemeteries in Northern China were analyzed to study the sequential changes of 31 cranial traits in the middle-to-late Holocene populations. Additionally, linear correlation analysis was employed to analyze the correlation between cranial traits and temperature. The results showed that directional long-term trends and local fluctuations occurred in the sequential changes. In the long-term trends, the neurocranial dimensions slightly decreased, while the viscerocranial dimensions showed a pattern of first decreasing and then increasing. The cranial length-height index changed from hypsicrany to orthocrany; the cranial breadth - height index changed from acrocrany to metriocrany; the orbital index increased from mesoconchy to hypsiconchy; the palatal index increased from mesostaphyliny to brachystaphyliny and then returned to mesostaphyliny.

Furthermore, many cranial traits (cranial height, neurocranial size, cranial capacity, cranial length-height index, and orbital index I) exhibited local fluctuations between 3000 and 2000 years ago. The cranial width and cranial index showed significant linear negative correlations with environmental temperature, while the cranial width - height index showed a significant linear positive correlation with environmental temperature. This phenomenon is intrinsically related to the role of the cranial pattern in regulating heat metabolism equilibrium. The maxillo-alveolar length, maxillo-alveolar breadth, and palatal length showed a significant linear positive correlation with environmental temperature. This relationship is related to the nutritional and masticatory functional impacts on the growth of the nasomaxillary complex, which are influenced by dietary shifts due to environmental temperature variations.

The imbalance between the long-term trends of neurocranial and viscerocranial dimensions is likely closely related to the differences in the mechanisms of cranial growth and development. The local fluctuating changes might be caused by the frequent communication and integration of various ethnic groups during the Xia, Shang, and Zhou Dynasties. Temperature is an important driving factor in the temporal changes of physical characteristics in the Northern Chinese populations during the Holocene. This study provides further insights into the evolution of physical traits in Chinese populations during the middle-to-late Holocene and sheds light on its intrinsic mechanism.