Scientists say that human faces are shrinking as we eat more processed foods.
An international team of archaeologists has traced the evolution of the human face, which has weakened over 100,000 years.
Neanderthals and monkeys have a pronounced ridge and broad faces with larger teeth. Ours began to become narrower when we learned to cook food, which means that we needed less powerful teeth and jaws to eat.
Researchers, including those from the universities of York and Hull, have tracked changes in the evolution of the face from the first humans that originated in Africa to our modern faces.
The study's author, Paul O & # 39; Higgins, professor of anatomy at the University of York, said: "Modern diets and smoother industrialized societies may mean that the human face continues to shrink in size.
"However, there are limits on how much the human face can change, for example, breathing requires a sufficiently large nasal cavity.
"However, within these limits, it is likely that the evolution of the human face will continue as long as our species survives, migrates and finds new environmental, social and cultural conditions."
Scientists say that the human face also evolved so that we could be more sociable and expressive with our eyebrows.
Humans developed a smooth forehead capable of a greater range of movement to express subtle emotions from recognition to sympathy.
Hairy eyebrows, more visible, were crucial for human social development in complex societies, scientists say.
Human faces were significantly reduced when we went from being hunter-gatherers to farmers, producing corn and wheat to make basic foods such as bread.
The theory is published in the journal Nature Ecology and Evolution.
Professor O & # 39; Higgins added: "We know that other factors, such as diet, respiratory physiology and climate, have contributed to the shape of the modern human face, but interpreting their evolution solely in terms of these factors would be an oversimplification .
"Now we can use our faces to point out more than 20 different categories of emotion through the contraction or relaxation of the muscles.
"It is unlikely that our first human ancestors had the same facial dexterity as the general shape of the face and the positions of the muscles were different."