Research from scientists at Oxford University has uncovered fascinating insights into the origins of kissing, suggesting that the practice may date back more than 20 million years, long before the emergence of modern humans. This study, published in the journal Evolution and Human Behavior, reveals that kissing is not merely a contemporary human behavior but is deeply rooted in our evolutionary history.
The research team conducted a comprehensive review of decades of studies involving primates, including chimpanzees, bonobos, and orangutans. By employing statistical modeling techniques, they estimated that an ancient ancestor of modern apes likely engaged in mouth-to-mouth contact between 16.9 million and 21.5 million years ago. This finding highlights the complex nature of kissing, which study lead author Matilda Brindle, an evolutionary biologist at Oxford, describes as an “evolutionary conundrum.”
Kissing presents an intriguing dilemma for evolution, as it carries notable risks, such as the potential spread of germs, and does not directly contribute to survival. Despite this, Brindle notes that across various primate species, kissing and similar behaviors may serve multiple functions, including social bonding and communication.
Tracing Kissing Through Time
While kissing seems to have ancient roots, the oldest written records of human kissing can be traced back approximately 4,500 years to civilizations in ancient Mesopotamia and Egypt. Interestingly, kissing is not a universal practice among humans. A study conducted in 2015 found that only 46% of people worldwide reported engaging in kissing.
Brindle elaborates on the evolutionary significance of kissing, stating, “We did find a strong evolutionary signal in kissing, but it doesn’t mean it has to be retained.” This suggests that while kissing may provide benefits in certain contexts, it may not be advantageous in others, especially considering the health risks involved.
The research team ran over 10 million simulations to assess the likelihood that early ape ancestors engaged in kissing behavior. Their findings support the notion that even extinct human relatives, such as Neanderthals, likely participated in similar practices.
Future Research Directions
Despite these remarkable insights, Brindle cautions that the model does not clarify the original purpose of kissing or the ways it has evolved over time. Much of the behavioral data gathered comes from animals in captivity, highlighting the need for further research on wild primates to gain a clearer understanding of the behavior’s origins.
Experts in the field recognize the importance of this study as a foundation for future exploration. Justin Garcia, an evolutionary biologist and director of The Kinsey Institute at Indiana University, noted the interplay of nature and nurture in the study of kissing. “Kissing is both biological and cultural,” he stated. Garcia emphasized that while kissing has clear evolutionary origins, its expression varies notably across different individuals and populations.
This research opens up new avenues for understanding how intimate behaviors, such as kissing, are influenced by both evolutionary biology and cultural practices, illustrating the complex tapestry of human interaction.
