A shift towards softer foods in ancient human diets, starting around the time of the Neolithic agricultural revolution, inadvertently changed the way our jaws develop. This resulted in a more common occurrence of overbites, where the upper teeth overlap the lower teeth. This change in jaw structure, in turn, facilitated the pronunciation of labiodental sounds like "f" and "v," which were less common in languages spoken by hunter-gatherer populations with edge-to-edge bites. The study used biomechanical modeling and analyzed phonetic data from a variety of languages, concluding that the overbite facilitates these sounds, offering a selective advantage in populations consuming softer foods.
A recent study published in Science suggests a strong correlation between the adoption of softer foods in human diets and the development of the overbite, a common dental trait where the upper teeth overlap the lower teeth. This shift, which began around the Neolithic era with the advent of agriculture and food processing techniques like milling and cooking, resulted in less wear and tear on human teeth. Consequently, the upper and lower incisors, no longer ground down by constant chewing of tough foods, maintained their juvenile alignment, where the upper teeth naturally project slightly forward. This previously uncommon "overbite" became the norm. The study further posits that this altered dental structure facilitated the emergence of labiodental sounds – sounds produced using the lips and teeth – such as "f" and "v." These sounds were difficult, if not impossible, to produce consistently with the edge-to-edge bite common in pre-agricultural humans. The research combined biomechanical modeling of tooth movement with analysis of modern and ancient skulls, as well as linguistic data on the prevalence of labiodental sounds in different languages. The findings challenge earlier assumptions about the origins of the overbite and propose a fascinating link between dietary changes, biological adaptation, and the evolution of human speech.
Summary of Comments ( 67 )
https://news.ycombinator.com/item?id=43117861
HN commenters discuss the methodology of the study, questioning the reliance on biomechanical models and expressing skepticism about definitively linking soft food to overbite development over other factors like genetic drift. Several users point out that other primates, like chimpanzees, also exhibit labiodental articulation despite not having undergone the same dietary shift. The oversimplification of the "soft food" category is also addressed, with commenters noting variations in food processing across different ancient cultures. Some doubt the practicality of reconstructing speech sounds based solely on skeletal remains, highlighting the missing piece of soft tissue data. Finally, the connection between overbite and labiodental sounds is challenged, with some arguing that an edge-to-edge bite is sufficient for producing these sounds.
The Hacker News comments section on the article "Ancient switch to soft food gave us overbite–the ability to pronounce 'f's,'v's" contains a robust discussion around the presented research. Several commenters express skepticism or challenge aspects of the study's methodology and conclusions.
One of the most compelling lines of discussion revolves around the difficulty of proving the causation link between softer foods and dental changes. Multiple commenters point out the correlation-causation problem, suggesting other factors could have contributed to the development of the overbite, such as changes in jaw musculature due to different tool use or genetic drift. One commenter specifically mentions the complexity of isolating the impact of food softness while other evolutionary pressures were also at play. They argue that the study might be oversimplifying a complex evolutionary process.
Another interesting point raised by several commenters concerns the ambiguity of "soft foods" in the context of pre-agricultural diets. Commenters question what constituted a "soft food" in those times, arguing that even cooked meats and vegetables would require significant chewing. They suggest that the study's definition of "soft food" might not accurately reflect the reality of ancient diets and thus could skew the findings. One comment even speculates on the potential role of cooking techniques, suggesting that boiling, for instance, might have softened foods more significantly than roasting.
Several commenters also delve into the linguistic aspects of the study, questioning the assertion that the overbite directly led to labiodental sounds (f, v). Some point to languages that utilize labiodental sounds without a prominent overbite as counterexamples. Others suggest that the connection between dental structure and sound production is more nuanced than presented in the study. One commenter specifically points to the existence of languages with bilabial fricatives (sounds similar to f and v but produced with both lips) as evidence that the overbite might not be strictly necessary for these types of sounds.
Furthermore, a few commenters discuss the study's reliance on biomechanical models. While acknowledging their usefulness, they highlight the limitations inherent in such models, especially when applied to complex systems like human evolution. They suggest that these models can oversimplify reality and might not fully capture the dynamic interplay of various factors influencing evolutionary changes.
Finally, some comments offer alternative hypotheses or expand upon the study's findings by linking them to other research on jaw development and human evolution. For example, one commenter proposes that the rise of agriculture and increased carbohydrate consumption might have played a more significant role in altering jaw structure. Another commenter mentions the impact of breastfeeding duration on facial development, suggesting this could be a contributing factor.
Overall, the Hacker News discussion provides a critical and insightful analysis of the study's claims. The commenters raise important questions about the methodology, interpretation, and implications of the research, contributing to a more nuanced understanding of the complex relationship between diet, dental morphology, and language evolution.