By David Graff, Dean’s Office, ENGINEERING. Translated by LeeAnn Iovanni, AAU Communication

In the Bronze Age, a special herpes variant began to spread suddenly to Europe. This is documented in a 2022 Cambridge study of teeth from human skeletons in Europe dating to 253-1,700 B.C. (see: https://www.cam.ac.uk/stories/ancientherpes). As an explanation for the spread at that particular time, the authors suggest that the kiss emerged as common social practice. 

But a new study conducted by behavioural biologist at Oxford and Aalborg University Sophie Lund Rasmussen along with her spouse, Assistant Professor of Assyriology Troels Pank Arbøll, University of Copenhagen, refutes this theory.

Photo: Troels Pank Arbøll and Sophie Lund Rasmussen in front of a picture of a relief from ancient Iraq (Mesopotamia) of a nude couple kissing in an embrace. The relief dates to approximately 1,800 B.C. and is exhibited at the British Museum.

This remark prompted the couple to initiate a joint research project that ended up both updating the cultural history of kissing and nuancing our understanding of the spread of disease in ancient times.

Kisses can always infect

The results of their research will be published as a perspective piece in the journal Science on May 19 under the heading 'The ancient history of kissing'.

She adds that this realisation is also relevant today:

- The issue of disease transmission speaks very much to current discussions about routes of transmission and the spread of disease. By adding new knowledge to these discussions, the perspective offers new historical depth in relation to, for example, human sexuality and infection transmission. These are themes we all encounter on an almost daily basis in these times.

Interdisciplinary and integrated knowledge

In interpreting the results of the cultural-historical studies of kissing in Mesopotamia, the couple employed several scientific disciplines. For example, they included both evolutionary and behavioural biological hypotheses about the purpose of the kiss's origin, the occurrence of the behaviour in chimpanzees and pygmy chimpanzees, as well as mapping via ancient DNA of infectious diseases that were already in circulation in ancient times and that can be transmitted via saliva.

Despite the many nuances included in the study, there is still more to explore, says Sophie Lund Rasmussen:

- There are studies that show that the romantic-erotic kiss is far from present in all cultures. What is the reason for this, and what impact can it have on the spread of infection and disease? And when did the kiss actually originate? The earliest documented example from Mesopotamia is around 2,500 B.C., but it suggests that the behaviour of kissing was practiced much earlier than that when the behaviour is also seen in our closest living relatives, the chimpanzees. These are some of the questions that remain unanswered, she concludes.