Koreans’ head size increases after independence

Prof. Im Joo Rhyu (College of Medicine) and his team releases MRI volumetric results

Intracranial volume of Koreans increases by 90ml due to social changes after Independence

▲ Prof. Im Joo Rhyu, Department of Anatomy, College of Medicine

It has been proved that the head size and shape of Koreans have changed dramatically since Independence. Professor Im Joo Rhyu and his research team at the Department of Anatomy, College of Medicine, have released study results proving that Koreans born in the 1970s have larger intracranial volume compared to Koreans born in the 1930s. Moreover, there have been changes in cranial shape of modern Koreans.

The team reported that the results were found using magnetic resonance imaging (MRI) to measure the heads of 115 Koreans born in the 1930s and 1970s, and restructuring them into three-dimensional images.

According to the research, the intracranial volume (volume within the skull) has increased by approximately 90ml for Koreans born in the 1970s, after Korea gained independence, compared to Koreans born in the 1930s, during the time when the country was socioeconomically unstable. These changes in skull shape were also evident: height, breadth and length all increased for males, and height and breadth increased for females. Since the Industrial Revolution, there have been reports from Western countries regarding morphological change of the skulls over one or two centuries caused by industrialization or urbanization, but for Koreans such changes occurred only within the past four decades.

This implies that Koreans born in the 1930s, during the period of Japanese colonialism, had growth and development issues caused by malnutrition due to economic troubles and social pressure, while Koreans born in the 1970s were supplied with adequate sources of nutrients within socioeconomically stable conditions.

Professor Im Joo Rhyu, the chief researcher said, ”Because we can estimate the size of the brain by measuring the intracranial volume and skull size, records on such measurements can be important indicators not only for physical anthropology but also for neuroscience and evolutionary anthropology.“ He noted that “This research proves that, apart from geographical or environmental reasons, the shape and size of Koreans’ heads changed for socioeconomic reasons.” He also added, “A well-balanced diet after socioeconomic development in the 1970s is what enabled the physical change.”

This research was supported by the Brain Korea 21 Plus Project and was published in the latest version of the American Journal of Physical Anthropology (AJPA), under the title ”Changes in intracranial volume and cranial shape in modern Koreans over four decades.” AJPA is a prestigious global journal with 100 years of history, and which ranked in the top 8.8% for anthropology category according to the Social Science Citation Index (SSCI) from Clarivate Analytics.

[Figure 1] 3D reconstruction of intracranial volume of Koreans born in the 1930s and 1970s

[Figure 2] Changes in intracranial volume, height, breadth and length of Korean males/females born in the 1930s and 1970s